Reduced antigen-induced proliferation and surface Ia expression of peripheral blood T cells following tetanus booster immunization.

Immune regulatory changes after tetanus booster immunization were studied by measuring T-cell proliferation and surface Ia expression after cocultivation of T cells with autologous tetanus toxoid pulsed macrophages. Both soluble and aluminium-absorbed tetanus toxoid was used as antigen. T cells proliferated readily prior to immunization, if TTAl was used as an antigen (when proliferation was measured by the uptake of [3H]thymidine: mean +/- SEM 64.5 +/- 11.5 X 10(3) dpm). The proliferative response of the peripheral blood T cells studied decreased significantly to 29.3 +/- 9.3 X 10(3) dpm (P less than 0.01) 1 week postimmunization, returned to preimmunization values after 2 to 4 weeks, and increased further thereafter. Surface Ia expression paralleled the proliferative response at every point pre- and postimmunization. Serum antibody levels increased steadily during the first weeks. These results demonstrate a functional parallel to the previously described changes in T-cell phenotypes (M. M. Eibl, J. W. Mannhalter, and G. Zlabinger, N. Engl. J. Med 310, 198, 1984) after tetanus booster immunization.