The Proceedings of the 7th Human Leukocyte Differentiation Antigen (HLDA) Workshop are about to be published, detailing more than 80 new CD specificities. The next Workshop, planned for 2004, will continue this process, and a number of candidate CD molecules in the literature, identified by antibody production or gene cloning, are listed in this update.

The process of categorizing the antigenic molecules and epitopes associated with human white cells, via the collaborative study of monoclonal antibodies, dates back to the early 1980s, when the first HLDA Workshop was held in Paris, France. This initial meeting listed only fifteen agreed molecular entities, but it created an internationally agreed basis for the nomenclature of leukocyte molecules (the CD scheme), and also provided a forum for reporting studies on their function and practical relevance. A further six HLDA meetings have been held since the first Paris meeting. The most recent of these (“HLDA7”) took place in 2000 in Harrogate, U.K., and the proceedings of the meeting will be published this year (Leucocyte Typing VII, Oxford University Press).

It was apparent at the previous meeting, HLDA6, held in Kobe, Japan, in 1996, that the technique of detecting molecular entities by screening coded panels of monoclonal antibodies against human cells was becoming obsolete. Antibodies to the most immunogenic molecules had already been produced, and fewer laboratories than in the early days were prepared to devote resources to raising new antibodies, since the probability of finding novel reagents becomes ever less likely. In consequence, many antibodies in the 6th Workshop were reagents (submitted by laboratories that were not equipped to characterize them) which proved to be of known specificity.

With these considerations in mind the 7th Workshop adopted a different approach; instead of screening poorly characterized antibodies, reagents were selected (and actively solicited) for which at least some molecular data were already available. A substantial number of monoclonal antibodies reactive with leucocyte-associated molecules exist that do not meet the traditional criterion for establishing a new CD specificity (i.e., the existence of at least two independent antibodies of the same specificity). This rule dates from the first HLDA Workshop two decades ago; since that time, biochemical and molecular biological techniques for characterizing the targets of new antibodies have come to be widely used. In consequence, it is now considered appropriate to establish a CD designation for a molecule if its gene has been cloned and at least one specific monoclonal antibody has been studied in the Workshop.

Four new sections were introduced in the 7th HLDA Workshop to add to the traditional list from past meetings: namely Dendritic Cells, Stem/Progenitor Cells, Erythroid Cells, and Carbohydrate Structures. Although it has been recognized for many years that monoclonal antibodies reactive with human leukocytes can be specific for carbohydrate epitopes (e.g., the carbohydrate CD category CD15 was identified at the first Workshop), they had not received specific attention in any Workshop. The inclusion of erythroid molecules, although it may seem out of place in a “Leukocyte Workshop,” was justified by the number of molecules shared between white and red cells (e.g., cytokine receptors) that hint at unexplored functions of red cells.

This more active approach to the identification of new CD specificities represented a break with tradition, but the results justified the new approach, since a total of well over 80 new entities were added to the list of CD specificities. This compares favorably with previous Workshops (an average of less than 30 CD specificities per Workshop), and it also largely avoided the laborious screening in multiple laboratories of antibodies that prove to be directed against known CD molecules.

Tables I and II list the new specificities established at the 7th Workshop. Full details will be found in Leucocyte Typing VII, and molecular, functional, and other data can be found for many of these new specificities on the Protein Reviews on the Web (PROW) Web site (http://www.ncbi.nlm.nih.gov/prow/).

Table I.

New CD designations

CD DesignationNameSectionLocus Link
CD15u Sulphated CD15 Carbohydrate structures  
CD60a GD3 Carbohydrate structures  
CD60b 9-O-acetyl-GD3 Carbohydrate structures  
CD60c 7-O-acetyl-GD3 Carbohydrate structures  
CD75 Lactosamines Carbohydrate structures  
CD75s α-2,6-sialylated lactosamines (formerly CDw75 and CDw76) Carbohydrate structures  
CD85 ILT/LIR family (see Table IIDendritic cells  
CD110 MPL, TPO R Platelets 4352 
CD111 PRR1/Nectin1 Myeloid cells 5818 
CD112 PRR2 Myeloid cells 5819 
CD133 AC133 Stem/progenitor cells 8842 
CD156b TACE/ADAM17 Adhesion structures 6868 
CD158 KIR family (see Table IINK cells  
CD159a NKG2A NK cells 3821 
CD160 BY55 T cells 11126 
CD162R PEN5 NK cells 6404 
CD167a Discoidin domain R (DDR1) Adhesion structures 780 
CD168 RHAMM Adhesion structures 3161 
CD169 Sialoadhesin Adhesion structures 6614 
CD170 Siglec-5 Adhesion structures 8778 
CD171 L1 Adhesion structures 3897 
CD172a SIRP α Adhesion structures 8194 
CD173 Blood group H type 2 Carbohydrate structures  
CD174 Lewis y Carbohydrate structures  
CD175 Tn Carbohydrate structures  
CD175s Sialyl-Tn Carbohydrate structures  
CD176 TF Carbohydrate structures  
CD177 NB1 Myeloid cells  
CD178 Fas ligand Cytokine/chemokine receptors 356 
CD179a Vpre-B B cells 7441 
CD179b λ5 B cells 3543 
CD180 RP105 B cells 4064 
CD183 CXCR3 Cytokine/chemokine receptors 2833 
CD184 CXCR4 Cytokine/chemokine receptors 7852 
CD195 CCR5 Cytokine/chemokine receptors 1234 
CDw197 CCR7 Cytokine/chemokine receptors 1236 
CD200 OX2 Nonlineage molecules 4345 
CD201 EPC R Endothelial cells 10544 
CD202b Tie2 (Tek) Endothelial cells 7010 
CD203c NPP3/PDNP3 Myeloid cells 5169 
CD204 Macrophage scavenger R Myeloid cells 4481 
CD205 DEC205 Dendritic cells 4065 
CD206 Macrophage mannose R Dendritic cells 4360 
CD207 Langerin Dendritic cells 50489 
CD208 DC-LAMP Dendritic cells  
CD209 DC-SIGN Dendritic cells 30385 
CDw210 IL-10R Cytokine/chemokine receptors 3587; 3588 
CD212 IL-12R Cytokine/chemokine receptors 3594 
CD213a1 IL-13Rα1 Cytokine/chemokine receptors 3597 
CD213a2 IL-13Rα2 Cytokine/chemokine receptors 3598 
CDw217 IL-17R Cytokine/chemokine receptors 23765 
CD220 Insulin R Nonlineage molecules 3643 
CD221 IGF1 R Nonlineage molecules 3480 
CD222 Mannose-6-phosphate/IGF2 R Nonlineage molecules 3482 
CD223 LAG-3 Nonlineage molecules 3902 
CD224 γ-glutamyl transferase Nonlineage molecules 2678 
CD225 Leu13 Nonlineage molecules 8519 
CD226 DNAM-1 (PTA1) T cells 10666 
CD227 MUC.1 Nonlineage molecules 4582 
CD228 Melanotransferrin Nonlineage molecules 4241 
CD229 Ly9 Nonlineage molecules 4063 
CD230 Prion protein Nonlineage molecules 5621 
CD231 TALLA-1/A15 Nonlineage molecules 7102 
CD232 VESP R Nonlineage molecules 10154 
CD233 Band 3 Erythroid cells 6521 
CD234 Fy-glycoprotein (DARC) Erythroid cells 2532 
CD235a Glycophorin A Erythroid cells 2993 
CD235b Glycophorin B Erythroid cells 2994 
CD235ab Glycophorin A/B crossreactive mAbs Erythroid cells  
CD236 Glycophorin C/D Erythroid cells  
CD236R Glycophorin C Erythroid cells 2995 
CD238 Kell Erythroid cells 3792 
CD239 B-CAM Erythroid cells 4059 
CD240CE Rh30CE Erythroid cells 6006 
CD240D Rh30D Erythroid cells 6007 
CD240DCE Rh30D/CE crossreactive mAbs Erythroid cells  
CD241 RhAg Erythroid cells 6005 
CD242 ICAM-4 Erythroid cells 3386 
CD243 MDR-1 Stem/progenitor cells  
CD244 2B4 NK cells 51744 
CD245 p220/240 T cells  
CD246 Anaplastic lymphoma kinase T cells 238 
CD247 ζ-chain T cells 919 
CD DesignationNameSectionLocus Link
CD15u Sulphated CD15 Carbohydrate structures  
CD60a GD3 Carbohydrate structures  
CD60b 9-O-acetyl-GD3 Carbohydrate structures  
CD60c 7-O-acetyl-GD3 Carbohydrate structures  
CD75 Lactosamines Carbohydrate structures  
CD75s α-2,6-sialylated lactosamines (formerly CDw75 and CDw76) Carbohydrate structures  
CD85 ILT/LIR family (see Table IIDendritic cells  
CD110 MPL, TPO R Platelets 4352 
CD111 PRR1/Nectin1 Myeloid cells 5818 
CD112 PRR2 Myeloid cells 5819 
CD133 AC133 Stem/progenitor cells 8842 
CD156b TACE/ADAM17 Adhesion structures 6868 
CD158 KIR family (see Table IINK cells  
CD159a NKG2A NK cells 3821 
CD160 BY55 T cells 11126 
CD162R PEN5 NK cells 6404 
CD167a Discoidin domain R (DDR1) Adhesion structures 780 
CD168 RHAMM Adhesion structures 3161 
CD169 Sialoadhesin Adhesion structures 6614 
CD170 Siglec-5 Adhesion structures 8778 
CD171 L1 Adhesion structures 3897 
CD172a SIRP α Adhesion structures 8194 
CD173 Blood group H type 2 Carbohydrate structures  
CD174 Lewis y Carbohydrate structures  
CD175 Tn Carbohydrate structures  
CD175s Sialyl-Tn Carbohydrate structures  
CD176 TF Carbohydrate structures  
CD177 NB1 Myeloid cells  
CD178 Fas ligand Cytokine/chemokine receptors 356 
CD179a Vpre-B B cells 7441 
CD179b λ5 B cells 3543 
CD180 RP105 B cells 4064 
CD183 CXCR3 Cytokine/chemokine receptors 2833 
CD184 CXCR4 Cytokine/chemokine receptors 7852 
CD195 CCR5 Cytokine/chemokine receptors 1234 
CDw197 CCR7 Cytokine/chemokine receptors 1236 
CD200 OX2 Nonlineage molecules 4345 
CD201 EPC R Endothelial cells 10544 
CD202b Tie2 (Tek) Endothelial cells 7010 
CD203c NPP3/PDNP3 Myeloid cells 5169 
CD204 Macrophage scavenger R Myeloid cells 4481 
CD205 DEC205 Dendritic cells 4065 
CD206 Macrophage mannose R Dendritic cells 4360 
CD207 Langerin Dendritic cells 50489 
CD208 DC-LAMP Dendritic cells  
CD209 DC-SIGN Dendritic cells 30385 
CDw210 IL-10R Cytokine/chemokine receptors 3587; 3588 
CD212 IL-12R Cytokine/chemokine receptors 3594 
CD213a1 IL-13Rα1 Cytokine/chemokine receptors 3597 
CD213a2 IL-13Rα2 Cytokine/chemokine receptors 3598 
CDw217 IL-17R Cytokine/chemokine receptors 23765 
CD220 Insulin R Nonlineage molecules 3643 
CD221 IGF1 R Nonlineage molecules 3480 
CD222 Mannose-6-phosphate/IGF2 R Nonlineage molecules 3482 
CD223 LAG-3 Nonlineage molecules 3902 
CD224 γ-glutamyl transferase Nonlineage molecules 2678 
CD225 Leu13 Nonlineage molecules 8519 
CD226 DNAM-1 (PTA1) T cells 10666 
CD227 MUC.1 Nonlineage molecules 4582 
CD228 Melanotransferrin Nonlineage molecules 4241 
CD229 Ly9 Nonlineage molecules 4063 
CD230 Prion protein Nonlineage molecules 5621 
CD231 TALLA-1/A15 Nonlineage molecules 7102 
CD232 VESP R Nonlineage molecules 10154 
CD233 Band 3 Erythroid cells 6521 
CD234 Fy-glycoprotein (DARC) Erythroid cells 2532 
CD235a Glycophorin A Erythroid cells 2993 
CD235b Glycophorin B Erythroid cells 2994 
CD235ab Glycophorin A/B crossreactive mAbs Erythroid cells  
CD236 Glycophorin C/D Erythroid cells  
CD236R Glycophorin C Erythroid cells 2995 
CD238 Kell Erythroid cells 3792 
CD239 B-CAM Erythroid cells 4059 
CD240CE Rh30CE Erythroid cells 6006 
CD240D Rh30D Erythroid cells 6007 
CD240DCE Rh30D/CE crossreactive mAbs Erythroid cells  
CD241 RhAg Erythroid cells 6005 
CD242 ICAM-4 Erythroid cells 3386 
CD243 MDR-1 Stem/progenitor cells  
CD244 2B4 NK cells 51744 
CD245 p220/240 T cells  
CD246 Anaplastic lymphoma kinase T cells 238 
CD247 ζ-chain T cells 919 
Table II.

New CD nomenclature for ILT/LIR and KIR moleculesa

CD DesignationName
The ILT/LIR family  
CD85a ILT5/LIR3 
CD85b ILT8 
CD85c LIR8 
CD85d ILT4/LIR2, MIR10 
CD85e ILT6/LIR4 
CD85f ILT11 
CD85g ILT7 
CD85h ILT1/LIR7 
CD85i LIR6 
CD85j ILT2/LIR1, MIR7 
CD85k ILT3/LIR5 
CD85l ILT9 
CD85m ILT10 
The KIR family  
CD158z KIR3DL7/KIRC1 
CD158b1 and KIR2DL2/p58.2 and 
CD158b2 KIR2DL3/p58.3 
CD158a KIR2DL1/p58.1 
CD158c KIR2DS6/KIRX 
CD158d KIR2DL4 
CD158e1 and KIR3DL1/p70 and 
CD158e2 KIR3DS1/p70 
CD158f KIR2DL5 
CD158g KIR2DS5 
CD158h KIR2DS1/p50.1 
CD158i KIR2DS4/p50.3 
CD158j KIR2DS2/p50.2 
CD158k KIR3DL2/p140 
CD DesignationName
The ILT/LIR family  
CD85a ILT5/LIR3 
CD85b ILT8 
CD85c LIR8 
CD85d ILT4/LIR2, MIR10 
CD85e ILT6/LIR4 
CD85f ILT11 
CD85g ILT7 
CD85h ILT1/LIR7 
CD85i LIR6 
CD85j ILT2/LIR1, MIR7 
CD85k ILT3/LIR5 
CD85l ILT9 
CD85m ILT10 
The KIR family  
CD158z KIR3DL7/KIRC1 
CD158b1 and KIR2DL2/p58.2 and 
CD158b2 KIR2DL3/p58.3 
CD158a KIR2DL1/p58.1 
CD158c KIR2DS6/KIRX 
CD158d KIR2DL4 
CD158e1 and KIR3DL1/p70 and 
CD158e2 KIR3DS1/p70 
CD158f KIR2DL5 
CD158g KIR2DS5 
CD158h KIR2DS1/p50.1 
CD158i KIR2DS4/p50.3 
CD158j KIR2DS2/p50.2 
CD158k KIR3DL2/p140 
a

For further details of this classification, based on the position of the genes on chromosome 19q;13.4 from centromeric to telomeric loci, see Ref. 1 .

Plans are well advanced for the 8th Workshop (see www.hlda8.org), to be organized in Adelaide, Australia, in 2004 under the aegis of Prof. H. Zola (Child Health Research Institute, Adelaide, Australia). It is sometimes assumed that the catalog of surface molecules associated with human hemopoietic cells is now essentially complete, but there is abundant evidence in the literature for novel surface molecules that would merit study at the next Workshop, and that could provide the basis for new CD designations. Table III comprises a list of potential new molecules reported following the production of monoclonal antibodies, and also a more extensive list of surface molecules identified via gene cloning. In most instances, no antibodies are available against the putative new leukocyte/endothelial markers in this latter group. Specific and well characterized reagents, whether monoclonal or polyclonal, are needed not only for detecting these new “virtual” molecules but also for defining functional domains, for characterizing three-dimensional protein structure, and for analyzing protein-protein interactions. It may be added that cloning of gene sequences often reveals multiple members of new or existing molecular families (e.g., the Toll-like receptors) and may identify surface receptors that bind more than one ligand or vice versa, (e.g., the TALL-1 and APRIL ligands for TACI and BCMA). Furthermore, a number of leukocyte-associated markers have been cloned from mice and other species, and almost all will have human homologues. The 8th Workshop will provide a forum for a range of antibody-based studies relating to this accumulating corpus of genomic and proteomic data.

Table III.

Examples of possible future CD specificities

MoleculeMolecule SizeCell TypesCommentsRefs.
Identified following antibody production     
AM-3K antigen 70 and 120 kDa Macrophages  Zeng L. et al., J. Pathol. 1996; 178:207. 
BDCA-2, BDCA-3, and BDCA-4 antigens  Dendritic cells Identifies subsets of dendritic cells Dzionek A. et al., J. Immunol. 2000; 165:6037. 
BENE 17 kDa Endothelium “Raft-associated” member of MAL family; interacts with caveolin-1 de Marco et al., J. Biol. Chem. 2001; 276:23009. 
CMRF-44 Dendritic cells Differentiated/activated Hock B. D. et al., Immunology 1994; 83:573. 
CMRF-56 95 kDa Dendritic cells Differentiated/activated Hock B. D. et al., Tissue Antigens 1999; 53:320. 
H47 antigen 100 kDa (non red.) 120 kDa (red.) T cells and most NK, B cells and monocytes ? Involved in T cell activation Hirohashi N. et al., Cell Immunol. 1993; 152:371. 
Hal-1 200 kDa (100 kDa) T cells, EBV-transformed B-cells, myelomonocytic cells, anaplastic large cell lymphoma ? New lymphoma marker Asanuma H. et al., Br. J. Haematol. 1999; 106:55. 
LAK1 and LAK2 antigens 120 kDa and 110+ 140 kDa respectively LGL and LAK cells  Zocchi M. R. et al., Cell Immunol. 1989; 124:144. 
NKp80 80 kDa dimer NK cells and CD56-positive T cells Novel member of the killer cell lectin-like receptor gene family, encoded by KLRF1 gene; triggers NK cell cytotoxicity Vitale M. et al., Eur. J. Immunol. 2001; 31:233. Roda-Navarro P. et al., Eur. J. Immunol. 2000; 30:568. 
VAP-1 (vascular adhesion protein) 90 kDa Endothelium Mediates lymphocyte-endothelial adhesion; has monoamine oxidase activity Bono P. et al., J. Immunol. 1998; 160:5563. Salmi M. and Jalkanen S. Science 1992; 257:1407. 
Wue-1 antigen 94 kDa Plasma cells Stimulates growth of plasma cells Greiner A. et al., Virchows Arch. 2000; 437:372. 
    (Table continues
MoleculeMolecule SizeCell TypesCommentsRefs.
Identified following antibody production     
AM-3K antigen 70 and 120 kDa Macrophages  Zeng L. et al., J. Pathol. 1996; 178:207. 
BDCA-2, BDCA-3, and BDCA-4 antigens  Dendritic cells Identifies subsets of dendritic cells Dzionek A. et al., J. Immunol. 2000; 165:6037. 
BENE 17 kDa Endothelium “Raft-associated” member of MAL family; interacts with caveolin-1 de Marco et al., J. Biol. Chem. 2001; 276:23009. 
CMRF-44 Dendritic cells Differentiated/activated Hock B. D. et al., Immunology 1994; 83:573. 
CMRF-56 95 kDa Dendritic cells Differentiated/activated Hock B. D. et al., Tissue Antigens 1999; 53:320. 
H47 antigen 100 kDa (non red.) 120 kDa (red.) T cells and most NK, B cells and monocytes ? Involved in T cell activation Hirohashi N. et al., Cell Immunol. 1993; 152:371. 
Hal-1 200 kDa (100 kDa) T cells, EBV-transformed B-cells, myelomonocytic cells, anaplastic large cell lymphoma ? New lymphoma marker Asanuma H. et al., Br. J. Haematol. 1999; 106:55. 
LAK1 and LAK2 antigens 120 kDa and 110+ 140 kDa respectively LGL and LAK cells  Zocchi M. R. et al., Cell Immunol. 1989; 124:144. 
NKp80 80 kDa dimer NK cells and CD56-positive T cells Novel member of the killer cell lectin-like receptor gene family, encoded by KLRF1 gene; triggers NK cell cytotoxicity Vitale M. et al., Eur. J. Immunol. 2001; 31:233. Roda-Navarro P. et al., Eur. J. Immunol. 2000; 30:568. 
VAP-1 (vascular adhesion protein) 90 kDa Endothelium Mediates lymphocyte-endothelial adhesion; has monoamine oxidase activity Bono P. et al., J. Immunol. 1998; 160:5563. Salmi M. and Jalkanen S. Science 1992; 257:1407. 
Wue-1 antigen 94 kDa Plasma cells Stimulates growth of plasma cells Greiner A. et al., Virchows Arch. 2000; 437:372. 
    (Table continues

As in the 7th Workshop in which four new sections were added, it may be possible to include neuronal cells in the 8th Workshop. Many neuronal cells express cell surface proteins found on leukocytes and vice versa (e.g., CD56, CD100, CD168, and CD171). Furthermore, the guidance cues used by neuronal cells sharesimilarities to those involved in leukocyte extravasation so the expression of these molecules in common may reflect shared biological processes. It may also be noted that other molecules such as the mucins thought to be primarily associated with epithelial cells, are now being described on leukocytes.

Finally, it remains to be established how the 8th and subsequent HLDA Workshops should deal with lineage- or stage-restricted leukocyte molecules that are localized within the cell cytoplasm (or nucleus). Given the importance of many of these molecules in signaling pathways initiated via known surface CD molecules, their identification and study is an inevitable extension of the work of the first seven HLDA Workshops. Whether or not a new “intracellular CD” categorization scheme is devised for such molecules, they are of interest for many laboratories interested in human hematopoietic cells, and their study will be among the aims of the next Workshop.

Table 3A.

Continued

MoleculeMolecule SizeCell TypesCommentsRefs.
Identified via gene cloning     
B cell maturation factor (BCMA) 184 aa B cells TNFR family member; receptor for TALL-1 and APRIL Madry et al., Int. Immunol. 1998; 10:1693. Shu H. B. and Johnson H., Proc. Natl. Acad. Sci. USA 2000; 97:9156. 
B7-H2 302 aa Dendritic cells New member of B7 family; binds ICOS on activated T cells Wang S. et al., Blood 2000; 96:2808. 
CLEC-1 280 aa Dendritic cells Novel C-type lectin-like receptor with cytoplasmic tyrosine-based motif Colonna M. et al., Eur. J. Immunol. 2000; 30:697. 
CMRF-35A 224 aa NK cells, neutrophils, monocytes, dendritic cells and subset of T lymphocytes Novel Ig superfamily receptors. CMRF-35H contains 3 cytoplasmic tyrosine based motifs Jackson et al., Eur. J. Immunol. 1992; 22:1157. 
CMRF-35H 300 aa   Green et al., Int. Immunol. 1998; 10:891. 
CS1  NK cells Novel receptor belonging to CD2 subset of Ig superfamily Boles K. S. et al., Immunogenetics 2001; 52:302. 
DC-STAMP 470 aa Dendritic cells Novel protein containing seven putative transmembrane domains. Hartgers F. C. et al., Eur. J. Immunol. 2000; 30:3585. 
EMR3 652 aa Mainly leukocyte restricted; highest levels on neutrophils, monocytes and macrophages Novel EGF-TM7 molecule. Interacts with a surface ligand on myeloid cells. Stacey M. et al., J. Biol. Chem. 2001; 276:18863. 
Flt-1 (VEGFR-1)  Endothelial cells, monocytes  Sawano A. et al., Blood 2001; 97:785. 
GPRv53 390 aa Leukocytes Identified by gene cloning; G-protein-coupled histamine receptor Oda T. et al., J. Biol. Chem. 2000; 275:36781. 
IRTA1 and IRTA2  Subpopulations of B cells Homologous to the Fc and inhibitory receptor families Hatzivassiliou G. et al., Immunity 2001; 14:277. 
M160 1453 aa Macrophages New member of scavenger receptor cysteine-rich superfamily Gronlund J. et al., J. Immunol. 2000; 165:6406. 
MARCO (macrophage receptor with collagenous structure) 520 aa Macrophages Class A scavenger receptor; involved in bacterial clearance in vivo Elomaa et al., J. Biol. Chem. 1998; 273:4530. Van der Laan L. J. et al., J. Immunol. 1999; 162:939. 
TACI 293 aa B cells TNFR family member. Receptor for TALL-1 and APRIL Xia X. Z. et al., J. Exp. Med. 2000; 192:137. 
TREM-1 and TREM-2 (triggering receptors expressed on myeloid cells)  Neutrophils and subset of monocytes (TREM-1) and macrophages (TREM-2) Novel Ig superfamily receptors. TREM-1 triggers neutrophil secretion (e.g. IL-8) and degranulation; TREM-2 activates macrophages; both associate with DAP12. Bouchon A. et al., J. Immunol. 2000; 164:4991. Daws M. R. et al., Eur. J. Immunol. 2001; 31:783. 
MoleculeMolecule SizeCell TypesCommentsRefs.
Identified via gene cloning     
B cell maturation factor (BCMA) 184 aa B cells TNFR family member; receptor for TALL-1 and APRIL Madry et al., Int. Immunol. 1998; 10:1693. Shu H. B. and Johnson H., Proc. Natl. Acad. Sci. USA 2000; 97:9156. 
B7-H2 302 aa Dendritic cells New member of B7 family; binds ICOS on activated T cells Wang S. et al., Blood 2000; 96:2808. 
CLEC-1 280 aa Dendritic cells Novel C-type lectin-like receptor with cytoplasmic tyrosine-based motif Colonna M. et al., Eur. J. Immunol. 2000; 30:697. 
CMRF-35A 224 aa NK cells, neutrophils, monocytes, dendritic cells and subset of T lymphocytes Novel Ig superfamily receptors. CMRF-35H contains 3 cytoplasmic tyrosine based motifs Jackson et al., Eur. J. Immunol. 1992; 22:1157. 
CMRF-35H 300 aa   Green et al., Int. Immunol. 1998; 10:891. 
CS1  NK cells Novel receptor belonging to CD2 subset of Ig superfamily Boles K. S. et al., Immunogenetics 2001; 52:302. 
DC-STAMP 470 aa Dendritic cells Novel protein containing seven putative transmembrane domains. Hartgers F. C. et al., Eur. J. Immunol. 2000; 30:3585. 
EMR3 652 aa Mainly leukocyte restricted; highest levels on neutrophils, monocytes and macrophages Novel EGF-TM7 molecule. Interacts with a surface ligand on myeloid cells. Stacey M. et al., J. Biol. Chem. 2001; 276:18863. 
Flt-1 (VEGFR-1)  Endothelial cells, monocytes  Sawano A. et al., Blood 2001; 97:785. 
GPRv53 390 aa Leukocytes Identified by gene cloning; G-protein-coupled histamine receptor Oda T. et al., J. Biol. Chem. 2000; 275:36781. 
IRTA1 and IRTA2  Subpopulations of B cells Homologous to the Fc and inhibitory receptor families Hatzivassiliou G. et al., Immunity 2001; 14:277. 
M160 1453 aa Macrophages New member of scavenger receptor cysteine-rich superfamily Gronlund J. et al., J. Immunol. 2000; 165:6406. 
MARCO (macrophage receptor with collagenous structure) 520 aa Macrophages Class A scavenger receptor; involved in bacterial clearance in vivo Elomaa et al., J. Biol. Chem. 1998; 273:4530. Van der Laan L. J. et al., J. Immunol. 1999; 162:939. 
TACI 293 aa B cells TNFR family member. Receptor for TALL-1 and APRIL Xia X. Z. et al., J. Exp. Med. 2000; 192:137. 
TREM-1 and TREM-2 (triggering receptors expressed on myeloid cells)  Neutrophils and subset of monocytes (TREM-1) and macrophages (TREM-2) Novel Ig superfamily receptors. TREM-1 triggers neutrophil secretion (e.g. IL-8) and degranulation; TREM-2 activates macrophages; both associate with DAP12. Bouchon A. et al., J. Immunol. 2000; 164:4991. Daws M. R. et al., Eur. J. Immunol. 2001; 31:783. 
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By permission of Oxford University Press.

1
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. New nomenclature for MHC receptors.
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