Histocompatibility antigens and genetic control of the immune response in guinea pigs. II. Specific inhibition of antigen-induced lymphocyte proliferation by anti-receptor alloantisera.

The in vitro recognition of acetylsalicilyl ovalbumin, penicilloylated bovine IgG (BPO-BGG) and the multichain copolymer poly-L-(Tyr, Glu)-poly-D L-Alapoly-L-Lys [(T, G)-A-L] by primed (2 x 13) F1 cells could be markedly and specifically blocked by alloantisera directed against "receptors" (R) or recognition structures for these antigens. The antisera were raised against lymphoid cells from various F2 hybrid guinea pigs of (2 x 13) histocompatibility type in which responsiveness to low doses of acetylsalicylic acid anhydride, BPO-BGG and (T, G)-A-L segregated independently of each other. One of the genes required for the expression of high responsiveness appears to be linked to the 13 MHC genes. The anti-R antisera did not contain antibodies capable of interacting directly with the stimulating antigen since passage of the sera through antigen-immunoadsorbent columns did not remove antibodies capable of suppressing in vitro recognition. Furthermore, the antisera did not appear to contain cytotoxic antibodies directed against specific antigen-sensitive cells. The activity of the anti-R sera was highly specific: their inhibitory activity could only be absorbed by lymphoid cells bearing the specific recognition structures for the appropriate antigen. Preliminary experiments yield no indication that the anti-R antisera are specific for immunoglobulin idiotypes.