Immunochemical Studies on the Specificity of Cellular Hypersensitivity

The immunochemical specificity of antigen-induced inhibition of peritoneal exudate cell migration was studied in animals sensitized to chemically defined alpha,DNP(Lys)(18) peptides. It was shown that sensitized peritoneal exudate cells could discriminate between various DNP-oligolysines. Only immunogenic members of the homologous series of alpha,DNP-L-lysines equal to or larger in size than the heptamer inhibited the migration of specifically sensitized peritoneal exudate cells. In contrast, nonimmunogenic alpha,DNP-L-lysines, a D-lysine containing stereoisomer of alpha,DNP L(Lys)(9) (alpha,DNP-L(4)DL(4)) and (Lys)(9)epsilon, DNP were not inhibitory to the migration of peritoneal exudate cells derived from animals immunized to alpha,DNP(Lys)(18). The exquisite specificity of the in vitro reaction of sensitized cells with antigen contrasts with the previously observed in vivo or in vitro specificity of anti-alpha,-DNP(Lys)(n) antibody, but parallels the specificity of the in vivo delayed or anamnestic response. These results suggest the presence of a still undefined but highly specific binding site, which functions as the cellular receptor for antigen on the sensitized lymphoid cell or on some "processing" cell.