IMMUNE RESPONSES IN VITRO : V. SUPPRESSION OFγM, γG,ANDγA PLAQUE-FORMING CELL RESPONSES IN CULTURES OF PRIMED MOUSE SPLEEN CELLS BY CLASS-SPECIFIC ANTIBODY TO MOUSE IMMUNOGLOBULINS

Suppression of Ig class-specific PFC responses by class-specific antibody to mouse immunoglobulin was studied in cultures of spleen cells from immunized mice. In contrast to cultures from normal mice where anti-µ suppressed responses in all Ig classes, anti-µ had progressively less suppressive effect on γ₁ and γ₂ responses in cultures from immunized mice with time after immunization. This was most pronounced at 10 days after immunization when anti-µ suppressed γM and γA responses, but had no or slight effect on γ₁ or γ₂ responses which were still suppressed with anti-γ₁ and anti-γ₂. These changes in precursor cell susceptibility to anti-µ were antigen specific.