Anti-ovalbumin (OA) IgE antibody responses were measured in B6D2F1 mice as a function of time and antigen dose. One hundred to 200 µg of OA in Al(OH)3 elicited transient responses, whereas 1 to 10 µg of OA in Al(OH)3 elicited persistent anti-OA IgE responses of high titer. T cells isolated from the spleens of mice mounting either a persistent or a transient response strongly suppressed primary anti-DNP IgE responses in unirradiated recipient mice that were immunized with DNP-OA in Al(OH)3; it was, therefore, concluded that suppressor T cells (Ts cells) were activated during both the persistent and transient IgE responses. Nevertheless, in the present study it was not possible to completely rule out the contention that IgG antibodies may also have been suppressing the IgE response. With a modified adoptive transfer system, it was shown that these Ts cells were sensitive to low doses (250 R) of x-irradiation. The suppressive activity of long-term OA primed cells was also shown to be markedly enhanced when cultured for 24 hr with soluble OA; this finding was interpreted to indicate the presence of memory suppressor cells.
This work was supported by grants from the Medical Research Council of Canada and the National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Md.