THE RESPONSE OF SPLEEN CELLS FROM IMMUNIZED RABBITS TO CROSS-REACTING ANTIGENS, IN AN IN VITRO SYSTEM

Abstract

Rabbits were immunized with bovine (BSA) or human (HSA) serum albumin. Spleen cell suspensions were prepared and incubated with the homologous or cross-reacting albumins. The antigen-dependent stimulation of the rate of DNA synthesis was used as a measure of the antigenic activity of each of the albumin preparations. The response was proportional to the logarithm of the antigen concentration for both the homologous and the cross-reacting albumins and the slopes of each curve were approximately the same. The cross-reacting albumins were less stimulatory than the homologous antigen. The pattern of their relative activities in this system followed the same pattern shown in their serological cross-reactions.