Systemic lupus erythematosus (SLE) can be induced in mice by immunizing them with a monoclonal human anti-DNA Ab that expresses a major Id, designated 16/6Id. In addition, a peptide based on the sequence of the CDR 1 (hCDR1) of the 16/6Id ameliorated the clinical manifestations of SLE in experimental models. In this study we examined the effects of treating mice with human complementary-determining region 1 (hCDR1) on the subsequent chemotaxis of T cells derived from 16/6Id-primed mice. First we demonstrated elevated levels of stromal cell-derived factor-1α (SDF-1α) in the sera of SLE-afflicted mice and in the sera and lymphoid tissues of 16/6Id-immunized BALB/c mice shortly after the immunization. We then found that administration of hCDR1 to 16/6Id-immunized mice specifically down-regulated SDF1α-induced T cell chemotaxis through fibronectin and collagen type I. This was accompanied by diminished SDF1-α-induced T cell adhesion and ERK phosphorylation. Treatment with hCDR1 up-regulated TGF-β secretion, which, in turn, inhibited the murine T cell adhesion to and chemotaxis through fibronectin as well as their ERK phosphorylation. Thus, the secretion of TGF-β after treatment of 16/6Id-immunized mice with hCDR1 plays an important role in the down-regulation of SDF-1α-mediated T cell activation and the interactions with extracellular matrix moieties observed in the present study.

Tcell entry into and functioning within extravascular sites of inflammation require their recognition of and interactions with the extracellular matrix (ECM),3 while responding to inflamed tissue-associated mediators, such as chemokines, cytokines, and growth factors ( 1, 2). These mediators enable the entrance of the cells into their designated sites of inflammation, because they affect T cell adhesion to and migration through the tissue’s ECM. These T cell functions are mediated primarily by ECM-specific receptors, including β1 integrins, which can send costimulatory signals into the cells and fine-tune their state of activation, functions, and orientation ( 3, 4).

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the increased production of autoantibodies and by modified T cell-mediated responses. The latter are associated with diverse clinical manifestations that involve multiple organ systems ( 5). Experimental SLE can be induced in naive, non-SLE-prone mice by immunization with monoclonal anti-DNA Abs that express the major Id, designated 16/6Id, of either human or mouse origin ( 6, 7). The 16/6Id-induced disease resembles SLE in humans and is manifested by high levels of autoantibodies (anti-dsDNA and anti-nuclear protein Ab) and by SLE-associated clinical symptoms. Two peptides based on the sequences of complementary-determining regions (CDR) 1 and 3 of the murine 16/6Id mAb were synthesized and shown to down-regulate autoreactive T cell responses ( 8). Treatment of mice with these peptides ameliorated the clinical manifestations of spontaneous and 16/6Id-induced SLE ( 9, 10, 11). The beneficial effects of this treatment were associated with a down-regulated secretion of IFN-γ, IL-10, and TNF-α and an up-regulation of TGF-β ( 9, 10). As a potential candidate for the treatment of SLE patients, a peptide based on the sequence of CDR1 of the human 16/6Id mAb, designated human CDR1 (hCDR1), was synthesized ( 12) and shown to ameliorate lupus manifestations in experimental models ( 13) and to specifically inhibit the 16/6Id-triggered in vitro proliferation and IL-2 production of PBL derived from SLE patients. The latter was correlated with up-regulated production of TGF-β ( 12)

Stromal cell-derived factor-1α (SDF-1α; CXCL12) is a pleiotropic CXC chemokine that affects the function of various cell types, including T cells, via its interactions with the CXCR4 receptor ( 14). In fact, SDF-1α plays a decisive role in regulating leukocyte proliferation, survival, and entry into sites of inflammation, in the induction of allergic responses, and activation of T cells within blood vessels and in extravascular sites, where it can act either in its matrix-bound or soluble forms ( 15, 16, 17, 18). Recently, elevated levels of SDF-1α in the kidneys of (NZB × NZW)F1 mice, during the course of the spontaneous development of SLE have been reported. Furthermore, SDF-1α was shown to be involved in the production of autoantibodies, Ig deposition, nephritis, and death of these SLE-prone mice ( 19).

The migratory behavior of T cells during SLE has still not been fully characterized. Moreover, the effects of the 16/6Id mAb and its CDR1-based peptide on T cell responses to SDF-1α and T cell interactions with ECM moieties are currently not known. Therefore, we wanted to find out whether the observed clinical benefits of the hCDR1 are also mediated by affecting the chemotaxis and interaction with the ECM of autoreactive T cells. We have found that T cells obtained from 16/6Id-immunized and hCDR1-treated mice shortly after priming showed a decrease in their adhesive and chemotactic responses to SDF-1α. In addition, this inhibitory response, which was correlated with an inhibition of SDF-1α-induced intracellular signaling and phosphorylation of β1 integrin-associated cytoskeletal proteins, was correlated with increased expression of TGF-β. The latter inhibited the murine T cell adhesion and chemotaxis in response to SDF-1α. Finally, the SDF-1α-induced migration of T cells derived from SLE-afflicted mice was also down-regulated after treatment with hCDR1.

Mice of the BALB/c inbred strain were obtained from Harlan. Female mice, aged 8–10 wk, were used.

The following reagents and chemicals were purchased from the sources indicated: RPMI 1640 (Invitrogen Life Technologies, Gaithersburg, MD); FCS, HEPES buffer, antibiotics, and sodium pyruvate (Kibbutz Beit-Haemek, Israel); fibronectin (FN) and collagen-I (COL-I; Chemicon International); and recombinant human SDF-1α (R&D Systems). Tissue culture plates were purchased from BD Biosciences Labware; anti-phosphorylated ERK1 and 2 mAbs (specific for the active, dual phosphorylated form) and anti-total ERK mAbs were obtained from Sigma-Aldrich. Na251[Cr]O4 was purchased from Amersham Biosciences.

A peptide based on the sequence of the CDR1 of the human anti-DNA mAb ( 19) that bears the major 16/6Id Id (GYYWSWIRQPPGKGEEWIG; designated hCDR1) was synthesized by Polypeptide Laboratories using solid phase synthesis by F-moc chemistry. Human CDR1 (TV4710) is currently under clinical development for the treatment of human SLE by TEVA Pharmaceutical Industries. As a control, we used a randomly synthesized peptide containing the amino acids of hCDR1 (SKGIPQYGGWPWEGWRYEI), designated scrambled peptide. This peptide binds MHC class II with a similar avidity to that of hCDR1 (unpublished data).

The human anti-DNA mAb that bears the 16/6Id (IgG1/κ) was previously described ( 20). The Ab is secreted by hybridoma cells that are grown in culture and is purified using a protein G-Sepharose column (Pharmacia Biotech).

Mice were immunized with the human mAb 16/6Id (1 μg in CFA) intradermally into the hind footpads. An additional group of immunized mice was injected s.c. with hCDR1 or with the scrambled peptide (50 μg/mouse) concomitant with immunization. Additional control groups of mice were similarly immunized with human IgG in CFA and either treated or not with hCDR1. Mice from all groups were killed on day 10 (unless mentioned otherwise), and their lymph node (LN)-derived T cells were studied.

To induce experimental SLE, BALB/c mice were immunized with the human mAb 16/6Id (1 μg in CFA) and boosted 3 wk later (1 μg in PBS). Treatment with hCDR1 started 3.5 mo after disease induction, when some clinical manifestations (e.g., anti-dsDNA Ab, leukopenia, and proteinuria) were already observed. Mice received 10 weekly injections (s.c.) of hCDR1 (50 μg/mouse) in PBS.

Preparation of enriched populations of LN-derived T cells was performed as follows. Petri dishes were precoated (overnight, 4°C) with goat anti-mouse Ig (15 μg/ml in 5 ml of PBS), then washed three times. Inguinal murine LN cells were incubated (70 min, 4°C, in RPMI 1640 containing 10% FCS and antibiotics) on the coated plates. The nonadherent cells, which were mainly T cells (>92%, as assessed by FACS analysis), were then collected and washed in RPMI 1640.

Extracts of LN and spleens were lysed using a homogenizer (20,000 rpm, 30 s) while being dissolved in 25 mM Tris (pH 7.5), 0.5 mM EDTA, 150 mM NaCl, 10 mM NaF, and protease inhibitor mixture (1% PMSF; Sigma-Aldrich). Total proteins in these extracts were quantified by Bradford assay, and equal protein amounts were assayed for SDF-1α as previously described ( 21). Serum samples from mice were tested for SDF-1α content using the same method. Briefly, ELISA plates (96 wells) were coated (18 h, 4°C) with mAb anti-SDF-1α. After the plates were washed and blocked with a buffer containing 1% BSA, samples were added at various dilutions and incubated (2 h, room temperature) with biotinylated mAb anti-SDF-1α, followed by the addition of 3,3′,5,5′-tetramethylbenzidine (Helix Diagnostics) substrate. The reaction was terminated by adding H2SO4 solution. OD was determined at 450 nm. The values of readings at 570 nm were then subtracted from the results.

T cell adhesion to immobilized protein substrates was analyzed as previously described ( 22). Briefly, flat-bottom microtiter plates were precoated with FN, and the remaining binding sites were blocked with PBS containing 0.1% BSA. Next, the purified murine LN-derived T cells were labeled with 51Cr and resuspended in RPMI 1640 medium supplemented with 1% HEPES buffer and 0.1% BSA (adhesion medium). The plates were incubated (60 min, 37°C in a 7.5% CO2 humidified atmosphere) and then gently washed. The adherent cells were lysed (in H2O containing 1 M NaOH and 0.1% Triton X-100), collected, and counted by a gamma counter (Packard). The results (±SD) are expressed as the mean percentage of bound T cells from quadruplicate wells. The chemotaxis of the LN-derived T cells was examined as described previously ( 23) using the 24-well chemotaxis microchambers (Transwell system; 6.5-mm diameter; Corning Glass). The polycarbonate membrane filters (5-μm pore size; Osmonics Proteins Products) separating the two compartments of the microchambers were precoated with FN or COL type I (1.25 μg/well). To induce T cell chemotaxis, SDF-1α (100 ng/ml) was added to the lower wells, and the radiolabeled T cells (2 × 105 cells/100 μl adhesion medium/well) were placed in the upper chambers. After completing the assay (3 h, 37°C in a 7% CO2 humidified atmosphere), the filters were removed, and the number of migrating T cells was determined by the level of radioactivity present in the lower wells. Control wells contained radioactive cells that migrated in the absence of SDF-1α. The results (±SD) are expressed as the mean percentage of migrating T cells from duplicate wells.

ERK phosphorylation was examined as previously described ( 23). Briefly enriched T cells were incubated in starvation medium (RPMI 1640 medium without serum) for at least 24 h before the experiments. Cells (5 × 106/sample) were activated with SDF-1α (100 ng/ml, 5–7 min, 37°C in a 7.5% CO2 humidified atmosphere). The reaction was terminated by freezing the cells (−70°C, 10 min). Next, the thawed cells were incubated (60 min, 4°C) in lysis buffer (containing EDTA (0.5 mM), NaCl (150 mM), NaF (10 nM), Tris (pH 7.5; 25 mM), Triton X-100 (1%), PMSF (200 μg/ml), and phosphatase inhibitor mixture (1%; Sigma-Aldrich)) and cleared by centrifugation (30 min, 14 × 103 rpm), and the supernatants were analyzed for protein content. Sample buffer was then added, and after boiling, the samples were separated on 10% SDS-PAGE gel and transferred to nitrocellulose membranes. The membranes were blocked using a TBST buffer (containing low fat milk (5%), Tris (pH 7.5; 20 mM), NaCl (135 mM), and Tween 20 (0.1%)) and probed with Ab anti-intact kinase and its phosphorylated form.

LN-derived cells were obtained from mice 10 days after immunization with 16/6Id mAb and the concomitant treatment with hCDR1. Cells (5 × 106) were incubated (enriched RPMI 1640 containing 7.5% FCS) in the presence of 16/6Id (25 μg/ml), and their supernatants were collected after 72 h. TGF-β1 was measured by ELISA according to the manufacturer’s instructions, using recombinant human TGF-β1 (sRII/Fc chimera; R&D Systems) for coating of the plates. Supernatants were added after activation of latent TGF-β1 to immunoreactive TGF-β1 by adding HCl and then neutralizing the acidified sample with NaOH (manufacturer’s instructions). A standard recombinant TGF-β1 was used as well. A biotinylated anti-human TGF-β1 (R&D Systems) was applied as the secondary Ab, the assay was developed using 3,3′,5,5′-tetramethylbenzidine color reagent (Helix Diagnostix), and enzyme activity was evaluated using 570- and 630-nm filters.

To determine whether the levels of SDF-1α are up-regulated in mice with 16/6Id-induced experimental SLE, we measured its presence in serum samples of SLE-afflicted BALB/c mice. Fig. 1,A demonstrates that the levels of SDF-1α in sera of mice with an established SLE induced by 16/6Id, e.g., 6 mo after the induction of disease, was almost 100-fold higher than that found in sera of normal mice (100 vs <1 ng/ml, respectively). Fig. 1 B shows that the levels of SDF-1α were elevated 10 days after immunizing the mice with 16/6Id mAb, well before the appearance of serological and clinical manifestations of SLE. It is noteworthy that levels of SDF-1α after immunization of mice with a nonrelated immunogen, namely OVA, were lower than those after 16/6Id immunization (data not shown). Thus, SDF-1α appears to be involved in the pathogenesis of experimental SLE.

FIGURE 1.

SDF-1α is increased in the serum and lymphoid organs of 16/6Id-immunized mice. The levels of SDF-1α in serum (A and B) and in the lymphoid tissues (C) of BALB/c mice were measured by ELISA. The levels of SDF-1α were analyzed 6 mo after the induction of experimental SLE by immunization and boost with 16/6Id (A) and in serum, spleens (SP), and LN of mice immunized 10 days previously with the16/6Id mAb in CFA (B and C). Depicted are the mean nanograms of SDF-1α± SD of 10 mice/group.

FIGURE 1.

SDF-1α is increased in the serum and lymphoid organs of 16/6Id-immunized mice. The levels of SDF-1α in serum (A and B) and in the lymphoid tissues (C) of BALB/c mice were measured by ELISA. The levels of SDF-1α were analyzed 6 mo after the induction of experimental SLE by immunization and boost with 16/6Id (A) and in serum, spleens (SP), and LN of mice immunized 10 days previously with the16/6Id mAb in CFA (B and C). Depicted are the mean nanograms of SDF-1α± SD of 10 mice/group.

Close modal

Next, we measured the levels of SDF-1α in the inguinal draining LN and the spleen, which absorbs blood-borne inflammatory mediators. The results, shown in Fig. 1 C, indicate that SDF-1α can be found in significant levels in these lymphoid organs in BALB/c mice by 10 days after their immunization with 16/6Id. Thus, lymphoid tissues can be viewed as a source of the elevated serum levels of SDF-1α.

The CDR-based peptides were shown to inhibit the proliferation of T cells derived from 16/6Id-immunized mice 10 days after priming ( 8). Given the putative role of SDF-1α in the 16/6Id-induced responses, we studied the effects of hCDR1 treatment of mice on the subsequent ability of their T cells to chemotactically migrate toward SDF-1α through immobilized ECM proteins in vitro using the Transwell system, in which the polycarbonate membranes separating the two compartments were precoated with either FN or COL-I. T cell migration was examined 7–19 days after the administration of 16/6Id concomitant with hCDR1 peptide. The freshly isolated T cells were radioactively labeled and added to the upper chamber, whereas SDF-1α was added to the lower compartment at the beginning of the 3-h assay. Fig. 2 shows the representative results of a series of such experiments. As shown, treatment of mice with hCDR1 resulted in a significant (p < 0.01) ex vivo inhibition of their SDF-1α-induced T cell chemotaxis through FN and COL-I (Fig. 2, A and B, respectively). The down-regulation of T cell chemotaxis was observed on days 10 and 12 after 16/6Id immunization and treatment with hCDR1 peptide; no inhibitory effect of the peptide could be observed 19 days after hCDR1 administration.

FIGURE 2.

Treatment of mice with hCDR1 concomitant with 16/6Id immunization specifically down-regulates SDF-1α-induced T cell migration. T cell migration was analyzed ex vivo on the indicated days after hCDR1 treatment. Purified murine T cells were labeled, washed, and added to the upper chambers of Transwell apparati, with or without 100 ng/ml SDF-1α, which was added to the lower chambers of the Transwell system at the beginning of the chemotaxis assay. The polycarbonate filters separating the two compartments were precoated with FN (A) or COL-I (B). After 3 h the cells that had transmigrated into the lower wells were collected, centrifuged, and lysed, and the radioactivity in the resulting supernatants was determined. To test the specificity of hCDR1 (C), T cells were isolated from LNs of 16/6Id-immunized BALB/c mice that were left untreated or were concomitantly treated with hCDR1 or with the control, scrambled peptide. In addition, depicted are the ex vivo SDF-1α migratory responses through FN of T cells obtained from BALB/c mice immunized with human IgG and treated with hCDR1. Shown are the mean results ± SD from one representative study of five different experiments that yielded essentially similar results. ∗, p < 0.05.

FIGURE 2.

Treatment of mice with hCDR1 concomitant with 16/6Id immunization specifically down-regulates SDF-1α-induced T cell migration. T cell migration was analyzed ex vivo on the indicated days after hCDR1 treatment. Purified murine T cells were labeled, washed, and added to the upper chambers of Transwell apparati, with or without 100 ng/ml SDF-1α, which was added to the lower chambers of the Transwell system at the beginning of the chemotaxis assay. The polycarbonate filters separating the two compartments were precoated with FN (A) or COL-I (B). After 3 h the cells that had transmigrated into the lower wells were collected, centrifuged, and lysed, and the radioactivity in the resulting supernatants was determined. To test the specificity of hCDR1 (C), T cells were isolated from LNs of 16/6Id-immunized BALB/c mice that were left untreated or were concomitantly treated with hCDR1 or with the control, scrambled peptide. In addition, depicted are the ex vivo SDF-1α migratory responses through FN of T cells obtained from BALB/c mice immunized with human IgG and treated with hCDR1. Shown are the mean results ± SD from one representative study of five different experiments that yielded essentially similar results. ∗, p < 0.05.

Close modal

We then tested the specificity of the inhibition by hCDR1. First, we compared its ex vivo migratory effect to that of T cells derived from mice treated with a control (scrambled) peptide. Next, we examined the effects of hCDR1 peptide in mice immunized with human IgG (because 16/6Id is also a human IgG) and compared the peptide’s effect on the latter to its effect on T cells of 16/6Id-immunized mice. SDF-1α-induced T cell migration was analyzed 10 days after immunization. As shown in Fig. 2,C, inhibition of T cell chemotaxis through FN was observed only in T cells obtained from 16/6Id-immunized and hCDR1-treated mice. Moreover, injection of mice with human IgG (but not 16/6Id) and hCDR1 did not affect SDF-1α-induced T cell migration through FN (Fig. 2 C). Thus, the inhibitory effect of hCDR1 peptide is specific to T cells obtained from 16/6Id-immunized mice.

We studied SDF-1α-induced adhesion of T cells isolated from mice 10 days after their immunization with 16/6Id and concomitant treatment with hCDR1. Treatment of mice with hCDR1 resulted in a significant (p < 0.001) down-regulation of SDF-1α-induced T cell adhesion to FN (Fig. 3 A). Thus, the ability of hCDR1 to inhibit T cell chemotaxis may be attributed to its ability to down-regulate SDF-1α-induced T cell adhesion to FN.

FIGURE 3.

Treatment of BALB/c mice with hCDR1 concomitant with 16/6Id immunization down-regulates SDF-1α-induced T cell adhesion and ERK phosphorylation. A, Labeled T cells from 16/6Id-immunized mice and hCDR1-treated mice were added to FN-coated microtiter well plates and incubated with or without 100 ng/ml SDF-1α. The wells were washed 60 min later, and adhesion of the remaining FN-bound T cells was measured. B, T cells were incubated with SDF-1α (250 ng/ml) for 5 and 7 min and lysed, and the extent of their intracellular ERK-phosphorylation was examined in their lysates. The lysates were run on SDS-PAGE, transferred to nitrocellulose membranes, and immunoblotted with anti-phospho-ERK (pERK) and anti-total-ERK (tERK) Abs. The densitometric histograms of the experiment are expressed as pERK/tERK × 100%. Shown are the results ± SD of one experiment representative of three that yielded an essentially similar pattern of results. ∗, p < 0.05.

FIGURE 3.

Treatment of BALB/c mice with hCDR1 concomitant with 16/6Id immunization down-regulates SDF-1α-induced T cell adhesion and ERK phosphorylation. A, Labeled T cells from 16/6Id-immunized mice and hCDR1-treated mice were added to FN-coated microtiter well plates and incubated with or without 100 ng/ml SDF-1α. The wells were washed 60 min later, and adhesion of the remaining FN-bound T cells was measured. B, T cells were incubated with SDF-1α (250 ng/ml) for 5 and 7 min and lysed, and the extent of their intracellular ERK-phosphorylation was examined in their lysates. The lysates were run on SDS-PAGE, transferred to nitrocellulose membranes, and immunoblotted with anti-phospho-ERK (pERK) and anti-total-ERK (tERK) Abs. The densitometric histograms of the experiment are expressed as pERK/tERK × 100%. Shown are the results ± SD of one experiment representative of three that yielded an essentially similar pattern of results. ∗, p < 0.05.

Close modal

Chemokine-induced activation of ERK plays a key role in signaling pathways associated with cell activation and their subsequent migration and adhesion ( 24, 25, 26). To study the effect of treatment with hCDR1 on ERK phosphorylation, we incubated murine T cells with SDF-1α (100 ng/ml) for 5–7 min and examined the extent of phosphorylated ERK1 and ERK2 in the cell lysates using a specific Ab. Treatment of 16/6Id-immunized mice with hCDR1 resulted in inhibition of the SDF-1α-induced ERK1 and ERK2 phosphorylation within the T cells (Fig. 3 B). As demonstrated in the densitometric analysis, this inhibition, which can be observed after 5 min of incubation with the chemokine, was even more prominent after 7 min of incubation. Thus, hCDR1 treatment of 16/6Id-immunzed mice results in the inhibition of SDF-1α-induced ERK activation in T cells.

TGF-β is a key modulator of inflammation, because it can down-regulate key T cell functions ( 27). Therefore, we first treated 16/6Id-immunized mice with hCDR1 and tested its effect on the secretion of TGF-β by their LN cells, obtained 10 days after immunization. As shown in Fig. 4 A, a significant elevation (from 360 to 760 pg/ml) in the levels of secreted TGF-β by the LN cells of hCDR1-treated mice was observed.

FIGURE 4.

Treatment with hCDR1 concomitant with 16/6Id immunization up-regulates TGF-β secretion, which down-regulates SDF-1α-induced migration of T cells obtained from 16/6Id-immunized mice. A, LNs were removed from BALB/c mice 10 days after immunization with 16/6Id. A single-cell suspension was prepared, and LN cells were incubated (72 h, tissue culture conditions) with 16/6Id (25 μg/ml). TGF-β was analyzed in the tissue culture supernatants by ELISA. T cells from mice immunized with 16/6Id (B) or immunized with 16/6Id and concomitantly treated with hCDR1 (C) were incubated (24 h) in vitro with the indicated concentrations of TGF-β, and their chemotaxis to SDF-1α was evaluated as described above. D, To confirm the role of TGF-β, T cells were obtained from BALB/c mice treated with hCDR1 concomitant with their immunization with 16/6Id. The purified cells were incubated (24 h) in vitro with mAb anti-TGF-β (10 μg/ml) or with the isotype control (10 μg/ml). SDF-1α-induced T cell migration through FN-coated filters was measured as described above. Depicted are the results of one experiment representative of four. ∗, p < 0.05.

FIGURE 4.

Treatment with hCDR1 concomitant with 16/6Id immunization up-regulates TGF-β secretion, which down-regulates SDF-1α-induced migration of T cells obtained from 16/6Id-immunized mice. A, LNs were removed from BALB/c mice 10 days after immunization with 16/6Id. A single-cell suspension was prepared, and LN cells were incubated (72 h, tissue culture conditions) with 16/6Id (25 μg/ml). TGF-β was analyzed in the tissue culture supernatants by ELISA. T cells from mice immunized with 16/6Id (B) or immunized with 16/6Id and concomitantly treated with hCDR1 (C) were incubated (24 h) in vitro with the indicated concentrations of TGF-β, and their chemotaxis to SDF-1α was evaluated as described above. D, To confirm the role of TGF-β, T cells were obtained from BALB/c mice treated with hCDR1 concomitant with their immunization with 16/6Id. The purified cells were incubated (24 h) in vitro with mAb anti-TGF-β (10 μg/ml) or with the isotype control (10 μg/ml). SDF-1α-induced T cell migration through FN-coated filters was measured as described above. Depicted are the results of one experiment representative of four. ∗, p < 0.05.

Close modal

Next, we examined the effect of treating T cells with TGF-β in vitro (24 h) on their subsequent chemotactic responses to SDF-1α. The T cells were obtained from BALB/c mice 10 days after their immunization with 16/6Id. Treatment of T cells with TGF-β resulted in an inhibition, in a dose-dependant manner, of their SDF-1α-induced migration (Fig. 4,B). A significant inhibition of chemotaxis was noted in the presence of 100 pg/ml TGF-β, and a maximal effect was achieved with 250 pg/ml TGF-β (p < 0.001). However, TGF-β did not affect the migratory pattern of T cells obtained from mice treated with hCDR1 concomitant with 16/6Id immunization (Fig. 4 C). Thus, the up-regulation of TGF-β in mice treated with hCDR1 may account for the inhibition of SDF-1α-induced migration of their T cells in vitro.

To confirm the central role of TGF-β in regulating the effect of the hCDR1 peptide on SDF-1α-induced T cell chemotaxis, we incubated (24 h) T cells derived from hCDR1-treated mice with different concentrations (5, 10, and 20 μg/ml) of anti-TGF-β mAb. Because the optimal inhibition was observed using 10 μg/ml (data not shown), this dose was used in all experiments. The TGF-β-specific mAb, but not its isotype control, completely abrogated the inhibitory effect of hCDR1; T cell migration toward SDF-1α after cell treatment with mAb anti-TGF-β was similar to that of 16/6Id-immunized murine T cells (Fig. 4 D). The significant effect of anti-TGF-β mAb was reproducible in four experiments, with a mean elevation of 42% in SDF-1α-induced chemotaxis of T cells derived from hCDR1-treated mice. Thus, the inhibition of SDF-1α-induced chemotaxis of T cells of hCDR1-treated mice is due to the hCDR1-induced elevated levels of TGF-β.

To elucidate the mechanism by which TGF-β down-regulates the SDF-1α-induced migration of T cells obtained from 16/6Id-immunized mice, we tested its effect on SDF-1α-induced T cell adhesion to FN and their intracellular ERK phosphorylation. TGF-β inhibited SDF-1α-induced adhesion to FN of T cells derived from 16/6Id-immunized mice (Fig. 5,A). In addition, incubation (24 h) of T cells with TGF-β resulted in a significant (p < 0.05) reduction of ERK phosphorylation 5 and 7 min after exposing the cells to SDF-1α (Fig. 5,B). The latter effect of TGF-β was similar to that seen in the T cells of mice previously treated with hCDR1 (Figs. 4 and 5). Thus, hCDR1 mediates its inhibitory effects on SDF-1α-induced adhesion and ERK phosphorylation via up-regulating TGF-β secretion.

FIGURE 5.

TGF-β down-regulates SDF-1α-induced adhesion to FN (A) and ERK phosphorylation (B) in T cells obtained from 16/6Id-immunized mice. T cells were obtained from BALB/c mice, immunized 10 days previously with 16/6Id, and their adhesion to immobilized FN was measured as described above. In addition, the combined effects of TGF-β and SDF-1α and their time kinetics on the intracellular phosphorylation of ERK (pERK) were examined. The results depicted here are from one experiment representative of five.

FIGURE 5.

TGF-β down-regulates SDF-1α-induced adhesion to FN (A) and ERK phosphorylation (B) in T cells obtained from 16/6Id-immunized mice. T cells were obtained from BALB/c mice, immunized 10 days previously with 16/6Id, and their adhesion to immobilized FN was measured as described above. In addition, the combined effects of TGF-β and SDF-1α and their time kinetics on the intracellular phosphorylation of ERK (pERK) were examined. The results depicted here are from one experiment representative of five.

Close modal

It was important to determine whether the inhibition of SDF-1α-induced T cell migration 10 days after 16/6Id immunization and concomitant treatment with hCDR1 could also be observed after treatment of mice with full-blown lupus. To this end, experimental SLE was induced in BALB/c mice by immunization and boosting with 16/6Id. Three and a half months after the boost (when clinical manifestations were evident), the mice were treated with hCDR1 once a week for 10 wk, and SDF-1α-induced T cell migration was determined at different time points. Fig. 6 represents the results of SDF-1α-induced migration of LN-derived T cells taken after nine weekly injections of hCDR1 to mice with experimental SLE. As shown in Fig. 6, treatment of mice with hCDR1 significantly down-regulated SDF-1α-induced T cell migration through FN (Fig. 6,A) and COL (Fig. 6 B). This effect was observed at the five time points tested, starting after five treatment injections of hCDR1.

FIGURE 6.

Treatment of SLE-afflicted mice with hCDR1 results in ex vivo inhibition of SDF-1α-induced T cell migration. Mice with induced experimental SLE were treated with hCDR1 once a week for 10 wk, and SDF-1α-induced LN-derived T cell migration through FN (A) and COL (B) was determined at different time points during and after treatment. Depicted are the results obtained after nine weekly injections of hCDR1. The results represent one of two long term experiments performed. ∗, p < 0.05.

FIGURE 6.

Treatment of SLE-afflicted mice with hCDR1 results in ex vivo inhibition of SDF-1α-induced T cell migration. Mice with induced experimental SLE were treated with hCDR1 once a week for 10 wk, and SDF-1α-induced LN-derived T cell migration through FN (A) and COL (B) was determined at different time points during and after treatment. Depicted are the results obtained after nine weekly injections of hCDR1. The results represent one of two long term experiments performed. ∗, p < 0.05.

Close modal

The main findings of this study are that immunization with the human mAb anti-DNA, designated 16/6Id, leads to an up-regulation of SDF-1α shortly after priming, and that treatment of BALB/c mice with hCDR1 concomitant with the immunization results in reduced SDF-1α-induced intracellular kinase-mediated signaling and in the ECM-adhesive and migratory potential of the murine LN cells. Furthermore, TGF-β, which is up-regulated in vivo after treatment with hCDR1, plays a key role in inhibiting the SLE-associated T cell responses to SDF-1α in vitro. To our knowledge, this is the first report that evaluates 1) ECM-associated migration of T cells specific to an SLE-inducing autoantibody, 2) the induction of this T cell migration by SDF-1α, and 3) the down-regulation of SDF-1α-induced migration by a peptide that has been previously shown to have clinical beneficial effects in mouse models of SLE ( 9, 10).

We have previously shown that experimental SLE can be induced in susceptible mice (e.g., BALB/c, C3H.SW, and SJL) by immunization with the 16/6Id ( 28), and that this disease resembles the human disease in terms of autoantibody and clinical manifestations ( 6). The central role played by T cells in this disease has been demonstrated by the ability of 16/6Id-specific T cell lines to induce experimental SLE in naive-recipient mice ( 29). Furthermore, depletion of CD4+ T cells inhibited the induction of experimental SLE by 16/6Id ( 30). Synthetic peptides based on the CDR1 and three of the 16/6Id mAb were shown to down-regulate the proliferative responses of T cells derived from 16/6Id-immunized mice ( 8). The peptides were also capable of preventing or treating established SLE that was either induced or developed spontaneously in SLE-prone mice ( 9, 10, 11). The inhibitory capacity of the CDR-based peptides was associated with down-regulation of the pathogenic cytokines (IFN-γ and IL-10), including the proinflammatory cytokines (TNF-α and IL-1β), and with increased secretion of the immunosuppressive cytokine TGF-β ( 9, 10, 12, 13). The present study was conducted 10 days after immunization with 16/6Id, well before the appearance of serological and clinical manifestations of experimental lupus, in an attempt to further clarify the mode of action of hCDR1. Our results show a down-regulated response to the disease-associated chemokine SDF-1α by T cells derived from peptide-treated mice. This down-regulation probably plays a role in the beneficial effects of hCDR1 on established SLE because treatment with hCDR1 also inhibited the SDF-1α-induced migration of T cells derived from SLE-afflicted mice (Fig. 6).

Although migrating into and through tissues, T cells encounter a variety of molecules within the ECM that affect their behavior and function, including adhesion and migration, and inflammatory mediator production and secretion. For example, SDF-1α can bind to FN and affect immune cell responses while being introduced to the cells in its FN complex form ( 31). We have previously found that although presented in the context of ECM in vitro, SDF-1α as well as RANTES (CCL5) and MIP-1β (CCL4) affected T cell adhesion and migration by activating their intracellular kinases and Ca2+ mobilization ( 32). SDF-1α is involved in the recruitment of blood-borne leukocytes to inflammatory sites of tissue transplants, and the chemokine is found in high levels in rheumatoid arthritis synovium ( 33) and in lupus that develops spontaneously in SLE-prone mice ( 19). In addition, the administration of SDF-1α antagonists in vivo prevented the production of autoantibodies associated with nephritis and the death of (NZB × NZW)F1 mice ( 19). In this study we found that the levels of SDF-1α in the sera of mice with full-blown experimental SLE induced by 16/6Id were markedly elevated. This elevation was evident in the sera, draining LNs, and spleens of BALB/c mice by 10 days postimmunization with 16/6Id (Fig. 1), suggesting that this chemokine might play a role in the pathogenesis of experimentally induced SLE.

T cells obtained from 16/6Id-immunized mice behaved differently from those obtained from syngeneic mice immunized with the SLE-inducing 16/6Id and concomitantly treated with the hCDR1. In the context of FN (or COL-I), T cells obtained from the peptide-treated mice showed markedly less adhesive and migratory responses to SDF-1α. This inhibition was associated with lower ERK activity, which is probably associated with the chemokine-induced morphological cell changes and β1 integrin activation. It is noteworthy that the apparent hCDR1-induced inhibition of T cell responses was evident not only in response to SDF-1α; T cell responses to the proinflammatory chemokine RANTES were also attenuated (data not shown). The down-regulation of the SDF-1α-induced chemotaxis after the injection of hCDR1 is specific, because the control, scrambled peptide administered concomitant with 16/6Id immunization did not affect T cell migration. Moreover, the inhibitory effects of hCDR1 were shown to be specific to SLE-associated responses only, because hCDR1 given concomitantly with the immunization of mice with human IgG did not affect the SDF-1α-induced migration of T cells isolated from the latter mice (Fig. 2 C).

The apparent inhibited T cell reactions were mostly significant 10 and 12 days after immunization of BALB/c mice with 16/6Id and concomitant injection of hCDR1. At this time, the peak T cell proliferative responses to 16/6Id were observed in cells of mice immunized with 16/6Id. In agreement, we have previously found that 10–12 days after immunization with 16/6Id and treatment with the CDR-based peptides, a significant inhibition of the 16/6Id-specific proliferative responses of LN-derived T cells could be obtained ( 8). This inhibition was also associated with the modulation of cytokine secretion. It is possible that the change in the profile of the secreted cytokines is associated with changes in the expression of the chemokines and acute phase reactants, which results in a modified T cell reaction to certain proinflammatory chemokines.

The inhibition by hCDR1 of SDF-1α-induced T cell adhesion and migration may be attributed to the in vivo up-regulation of secretion of the immunomodulatory cytokine TGF-β, which also occurred 10 days postimmunization. TGF-β is associated with wound healing, amelioration of inflammatory reactions and autoimmune diseases, and angiogenesis (reviewed in Refs. 34, 35, 36). Both constitutive and stimulated levels of TGF-β were shown to be low in SLE patients, especially during active disease ( 37). Interestingly, SLE-like disease was shown to develop in TGF-β knockout mice ( 38), whereas up-regulation of TGF-β production in the lupus-prone MRL/lpr/lpr mice decreased autoantibody production ( 39). Our previous observations also demonstrated that although other cytokines (e.g., IFN-γ and IL-10) were down-regulated by the CDR-based peptides, up-regulation of TGF-β secretion was associated with the beneficial effects of the peptides ( 9, 10, 12, 13). Also, inhibition of anti-DNA Ab production and improvement in clinical manifestations were associated with up-regulated TGF-β secretion ( 40, 41). Importantly, TGF-β can regulate the chemotaxis of human leukocytes ( 42, 43). It activates MAPK, and in certain types of cells, elevates the phosphorylation level of focal adhesion proteins, such as Raf-MEK-MAPK, focal adhesion kinase, and paxillin ( 44), which are involved in the formation of focal adhesion sites and cell-cell or cell-ECM interactions. We have recently found that a prolonged in vitro exposure of naive human T cells to small amounts (<0.5 ng/ml) of TGF-β increased their migratory response to SDF-1α. In contrast, larger amounts of TGF-β, i.e., 500-1000 pg/ml, were found to inhibit human T cell chemotaxis to SDF-1α ( 23, 45). Note that similar concentration ranges of TGF-β were secreted by the immunocytes of mice treated with the hCDR1 peptide (Fig. 4,A). In addition, such concentrations of TGF-β were shown to inhibit the SDF-1α-induced chemotaxis and adhesion of T cells derived from 16/6Id-immunized mice (Figs. 4,B and 5 A). The role of TGF-β in the inhibitory activity of hCDR1 on in vitro SDF-1α-induced T cell chemotaxis was confirmed by demonstrating that anti-TGF-β abrogated the effect of hCDR1 treatment. The inhibition of T cell activities after treatment with hCDR1 or incubation with TGF-β is associated with a significant down-regulation of intracellular SDF-1α-induced ERK signaling. Interestingly, it was previously shown that TGF-β inhibited T cell ERK phosphorylation induced upon TCR/CD28 ligation ( 46)

Taken together, our findings suggest the existence of a mechanism by which the hCDR1 peptide exerts its specific inhibiting capacities in vivo. The apparent down-regulation of murine T cell responses to SDF-1α is most likely a consequence of the peptide-induced up-regulation of TGF-β secretion. We postulate that when present in relatively high concentrations, this cytokine can down-regulate T cell activation and interactions with ECM glycoproteins (Fig. 7). Such interactions are vital for the maintenance of chronic inflammatory reactions. Suppression of the latter may lead to the down-regulation of early autoreactive T cell responses shown in this report and possibly to amelioration of the later-developing SLE manifestations.

FIGURE 7.

Sequence of events leading to inhibition of SDF-1α-induced T cell migration by hCDR1.

FIGURE 7.

Sequence of events leading to inhibition of SDF-1α-induced T cell migration by hCDR1.

Close modal

The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

1

This work was supported by the Minerva Foundation, funded by the Committee for Scientific Cooperation between Germany and Israel; by the Israel Science Foundation, funded by the Israel Academy of Sciences and Humanities (to O.L.); and by TEVA Pharmaceutical Industries, Israel (to E.M.).

3

Abbreviations used in this paper: ECM, extracellular matrix; COL, collagen; CDR, complementarity-determining region; FN, fibronectin; hCDR, human CDR; LN, lymph node; SDF-1α, stromal cell-derived factor-1α; SLE, systemic lupus erythematosus.

1
Vaday, G. G., H. Schor, M. A. Rahat, N. Lahat, O. Lider.
2001
. Transforming growth factor-β suppresses tumor necrosis factor α-induced matrix metalloproteinase-9 expression in monocytes.
J. Leukocyte Biol.
69
:
613
.
2
Pribila, J. T., Y. Shimizu.
2003
. Signal transduction events regulating integrin function and T cell migration: new functions and complexity.
Immunol. Res.
27
:
107
.
3
Dustin, M. L., D. A. Fougerolles.
2001
. Reprogramming T cells: the role of extracellular matrix in coordination of T cell activation and migration.
Curr. Opin. Immunol.
13
:
286
.
4
Woods, M. L., Y. Shimizu.
2001
. Signaling networks regulating β1 integrin-mediated adhesion of T lymphocytes to extracellular matrix.
J. Leukocyte Biol.
69
:
874
.
5
Hahn, B. H..
1993
. An overview of the pathogenesis of systemic lupus erithematosus. B. H. Hahn, and D. J. Wallace, eds.
Dubois’ Lupus Erithematosus
69
. Williams & Wilkins Lippincott, Philadelphia.
6
Mendlovic, S., S. Brocke, Y. Shoenfeld, M. Ben-Bassat, A. Meshorer, R. Bakimer, E. Mozes.
1988
. Induction of a systemic lupus erythematosus-like disease in mice by a common human anti-DNA idiotype.
Proc. Natl. Acad. Sci. USA
85
:
2260
.
7
Waisman, A., S. Mendlovic, P. J. Ruiz, H. Zinger, A. Meshorer, E. Mozes.
1993
. The role of the 16/6 idiotype network in the induction and manifestations of systemic lupus erythematosus.
Int. Immunol.
5
:
1293
.
8
Waisman, A., P. J. Ruiz, E. Israeli, E. Eilat, S. Konen-Waisman, H. Zinger, M. Dayan, E. Mozes.
1997
. Modulation of murine systemic lupus erythematosus with peptides based on complementarity determining regions of a pathogenic anti-DNA monoclonal antibody.
Proc. Natl. Acad. Sci. USA
94
:
4620
.
9
Zinger, H., E. Eilat, A. Meshorer, E. Mozes.
2003
. Peptides based on the complementarity-determining regions of a pathogenic autoantibody mitigate lupus manifestations of (NZB × NZW)F1 mice via active suppression.
Int. Immunol.
15
:
205
.
10
Eilat, E., M. Dayan, H. Zinger, E. Mozes.
2001
. The mechanism by which a peptide based on complementarity-determining region-1 of a pathogenic anti-DNA auto-Ab ameliorates experimental systemic lupus erythematosus.
Proc. Natl. Acad. Sci. USA
98
:
1148
.
11
Eilat, E., H. Zinger, A. Nyska, E. Mozes.
2000
. Prevention of systemic lupus erythematosus-like disease in (NZB×NZW)F1 mice by treating with CDR1- and CDR3-based peptides of a pathogenic autoantibody.
J. Clin. Immunol.
20
:
268
.
12
Sthoeger, Z. M., M. Dayan, A. Tcherniack, L. Green, S. Toledo, R. Segal, O. Elkayam, E. Mozes.
2003
. Modulation of autoreactive responses of peripheral blood lymphocytes of patients with systemic lupus erythematosus by peptides based on human and murine anti-DNA autoantibodies.
Clin. Exp. Immunol.
131
:
385
.
13
Luger, D., M. Dayan, H. Zinger, J. P. Liu, and E. Mozes. A peptide based on the complementarity determining region 1 of human monoclonal autoantibody ameliorates spontaneous and induced lupus manifestations in correlation with cytokine immunomodulation. J. Clin. Immunol. In press.
14
Nagasawa, T., K. Tachibana, T. Kishimoto.
1998
. A novel CXC chemokine PBSF/SDF-1 and its receptor CXCR4: their functions in development, hematopoiesis and HIV infection.
Semin. Immunol.
10
:
179
.
15
Lataillade, J. J., D. Clay, C. Dupuy, S. Rigal, C. Jasmin, P. Bourin, M. C. Le Bousse-Kerdiles.
2000
. Chemokine SDF-1 enhances circulating CD34+ cell proliferation in synergy with cytokines: possible role in progenitor survival.
Blood
95
:
756
.
16
Jinquan, T., H. H. Jacobi, C. Jing, C. M. Reimert, S. Quan, S. Dissing, L. K. Poulsen, P. S. Skov.
2000
. Chemokine stromal cell-derived factor 1α activates basophils by means of CXCR4.
J. Allergy Clin. Immunol.
106
:
313
.
17
Wright, N., A. Hidalgo, J. M. Rodriguez-Frade, S. F. Soriano, M. Mellado, M. Parmo-Cabanas, M. J. Briskin, J. Teixido.
2002
. The chemokine stromal cell-derived factor-1α modulates α4β7 integrin-mediated lymphocyte adhesion to mucosal addressin cell adhesion molecule-1 and fibronectin.
J. Immunol.
168
:
5268
.
18
Cinamon, G., V. Grabovsky, E. Winter, S. Franitza, S. Feigelson, R. Shamri, O. Dwir, R. Alon.
2001
. Novel chemokine functions in lymphocyte migration through vascular endothelium under shear flow.
J. Leukocyte Biol.
69
:
860
.
19
Balabanian, K., J. Couderc, L. Bouchet-Delbos, A. Amara, D. Berrebi, A. Foussat, F. Baleux, A. Portier, I. Durand-Gasselin, R. L. Coffman, et al
2003
. Role of the chemokine stromal cell-derived factor 1 in autoantibody production and nephritis in murine lupus.
J. Immunol.
170
:
3392
.
20
Waisman, A., Y. Shoenfeld, M. Blank, P. J. Ruiz, E. Mozes.
1995
. The pathogenic human monoclonal anti-DNA that induces experimental systemic lupus erythematosus in mice is encoded by a VH4 gene segment.
Int. Immunol.
7
:
689
.
21
Petit, I., M. Szyper-Kravitz, A. Nagler, M. Lahav, A. Peled, L. Habler, T. Ponomaryov, R. S. Taichman, F. Arenzana-Seisdedos, N. Fujii, et al
2002
. G-CSF induces stem cell mobilization by decreasing bone marrow SDF-1 and up-regulating CXCR4.
Nat. Immunol.
3
:
687
.
22
Ariel, A., E. J. Yavin, R. Hershkoviz, A. Avron, S. Franitza, I. Hardan, L. Cahalon, M. Fridkin, O. Lider.
1998
. IL-2 induces T cell adherence to extracellular matrix: inhibition of adherence and migration by IL-2 peptides generated by leukocyte elastase.
J. Immunol.
161
:
2465
.
23
Franitza, S., O. Kollet, A. Brill, G. G. Vaday, I. Petit, T. Lapidot, R. Alon, O. Lider.
2002
. TGF-β1 enhances SDF-1α-induced chemotaxis and homing of naive T cells by up-regulating CXCR4 expression and downstream cytoskeletal effector molecules.
Eur. J. Immunol.
32
:
193
.
24
Boehme, S. A., S. K. Sullivan, P. D. Crowe, M. Santos, P. J. Conlon, P. Sriramarao, K. B. Bacon.
1999
. Activation of mitogen-activated protein kinase regulates eotaxin-induced eosinophil migration.
J. Immunol.
163
:
1611
.
25
Weber, K. S., G. Ostermann, A. Zernecke, A. Schroder, L. B. Klickstein, C. Weber.
2001
. Dual role of H-Ras in regulation of lymphocyte function antigen-1 activity by stromal cell-derived factor-1α: implications for leukocyte transmigration.
Mol. Biol. Cell
12
:
3074
.
26
Woo, C. H., M. H. Yoo, H. J. You, S. H. Cho, Y. C. Mun, C. M. Seong, J. H. Kim.
2003
. Transepithelial migration of neutrophils in response to leukotriene B4 is mediated by a reactive oxygen species-extracellular signal-regulated kinase-linked cascade.
J. Immunol.
170
:
6273
.
27
Luethviksson, B. R., B. Gunnlaugsdottir.
2003
. Transforming growth factor-β as a regulator of site-specific T-cell inflammatory response.
Scand. J. Immunol.
58
:
129
.
28
Mendlovic, S., S. Brocke, H. Fricke, Y. Shoenfeld, R. Bakimer, E. Mozes.
1990
. The genetic regulation of the induction of experimental SLE.
Immunology
69
:
228
.
29
Fricke, H., S. Mendlovic, M. Blank, Y. Shoenfeld, M. Ben-Bassat, E. Mozes.
1991
. Idiotype specific T-cell lines inducing experimental systemic lupus erythematosus in mice.
Immunology
73
:
421
.
30
Ruiz, P. J., H. Zinger, E. Mozes.
1996
. Effect of injection of anti-CD4 and anti-CD8 monoclonal antibodies on the development of experimental systemic lupus erythematosus in mice.
Cell. Immunol.
167
:
30
.
31
Pelletier, A. J., L. J. van der Laan, P. Hildbrand, M. A. Siani, D. A. Thompson, P. E. Dawson, B. E. Torbett, D. R. Salomon.
2000
. Presentation of chemokine SDF-1α by fibronectin mediates directed migration of T cells.
Blood
96
:
2682
.
32
Hecht, I., L. Cahalon, R. Hershkoviz, A. Lahat, S. Franitza, O. Lider.
2003
. Heterologous desensitization of T cell functions by CCR5 and CXCR4 ligands: inhibition of cellular signaling, adhesion and chemotaxis.
Int. Immunol.
15
:
29
.
33
Nanki, T., K. Hayashida, H. S. El-Gabalawy, S. Suson, K. Shi, H.J. Girschick, S. Yavuz, P. E. Lipsky.
2000
. Stromal cell-derived factor-1-CXC chemokine receptor 4 interactions play a central role in CD4+ T cell accumulation in rheumatoid arthritis synovium.
J. Immunol.
165
:
6590
.
34
Marek, A., J. Brodzicki, A. Liberek, M. Korzon.
2002
. TGF-β (transforming growth factor-β) in chronic inflammatory conditions: a new diagnostic and prognostic marker?.
Med. Sci. Monit.
8
:
RA145
.
35
Letterio, J. J., A. B Roberts.
1998
. Regulation of immune responses by TGF-β.
Annu. Rev. Immunol.
16
:
137
.
36
Dean, G. S., J. Tyrrell-Price, E. Crawley, D. A. Isenberg.
2000
. Cytokines and systemic lupus erythematosus.
Ann. Rheum. Dis.
59
:
243
.
37
Ohtsuka, K., J. D. Gray, M. M. Stimmler, B. Toro, D. A. Horwitz.
1998
. Decreased production of TGF-β by lymphocytes from patients with systemic lupus erythematosus.
J. Immunol.
160
:
2539
.
38
Yaswen, L., A. B. Kulkarni, T. Fredrickson, B. Mittleman, R. Schiffman, S. Payne, G. Longenecker, E. Mozes, S. Karlsson.
1996
. Autoimmune manifestations in the transforming growth factor-β1 knockout mouse.
Blood
87
:
1439
.
39
Raz, E., J. Dudler, M. Lotz, S. M. Baird, C. C. Berry, R. A. Eisenberg, D. A. Carson.
1995
. Modulation of disease activity in murine systemic lupus erythematosus by cytokine gene delivery.
Lupus
4
:
286
.
40
Singh, R. R., F. M. Ebling, D. A. Albuquerque, V. Saxena, V. Kumar, E. H. Giannini, T. N. Marion, F. D. Finkelman, B. H. Hann.
2002
. Induction of autoantibody production is limited in nonautoimmune mice.
J. Immunol.
169
:
1647
.
41
Fan, G. C., R. R. Singh.
2002
. Vaccination with minigenes encoding VH-derived major histocompatibility complex class I-binding epitopes activates cytotoxic T cells that ablate autoantibody-producing B cells and inhibit lupus.
J. Exp. Med.
196
:
731
.
42
Sato, K., H. Kawasaki, H. Nagayama, M. Enomoto, C. Morimoto, K. Tadokoro, T. Juji, T. A. Takahashi.
2000
. TGF-β1 reciprocally controls chemotaxis of human peripheral blood monocyte-derived dendritic cells via chemokine receptors.
J. Immunol.
164
:
2285
.
43
Olsson, N., E. Piek, P. ten Dijke, G. Nilsson.
2000
. Human mast cell migration in response to members of the transforming growth factor-β family.
J. Leukocyte Biol.
67
:
350
.
44
Axmann, A., D. Seidel, T. Reimann, U. Hempel, K. W. Wenzel.
1998
. Transforming growth factor-β1-induced activation of the Raf-MEK-MAPK signaling pathway in rat lung fibroblasts via a PKC-dependent mechanism.
Biochem. Biophys. Res. Commun.
249
:
456
.
45
Brill, A., S. Franitza, O. Lider, R. Hershkoviz.
2001
. Regulation of T-cell interaction with fibronectin by transforming growth factor-β is associated with altered Pyk2 phosphorylation.
Immunology
104
:
149
.
46
Chen, C. H., C. Seguin-Devaux, N. A. Burke, T. B. Oriss, S. C. Watkins, N. Clipstone, A. Ray.
2003
. Transforming growth factor β blocks Tec kinase phosphorylation, Ca2+ influx, and NFATc translocation causing inhibition of T cell differentiation.
J. Exp. Med.
197
:
1689
.