Competition of 19S and 7S antigen receptors in the regulation of the primary immune response.

Prior to sheep red cells (SRC) mice were given 7S or 19S anti-SRC antibodies or mixtures of both. All 7S preparations suppressed the immune response. All 19S preparations enhanced the primary response, as measured by an up to 15-fold increase in the number of PFC per spleen. Results obtained with mixtures showed that 7S and 19S antibodies are competitive in their effect. The kinetics of the appearance of PFC in the mouse spleen after injection of SRC suggest that the depressive effect of 7S antibody simulates a reduction in SRC dose, whereas the enhancing effect of 19S antibody appears as a temporary increase in the rate at which PFC appear. Antibodies from one animal species are quite effective in another species.