Allorestriction and xenorestriction phenomena in the induction of delayed-type hypersensitivity (DTH) responses in the guinea pig against azobenzenearsonate- (ABA) modified peritoneal exudate cells.

The role of MHC products in the induction of DTH responses Ia antigens play a crucial role in these cells in the recognition of ABA determinants by lymphocytes. Second, JY-1 guinea pigs were employed as responder animals. A clear allorestriction phenomenon was observed again when weakly modified ABA-PEC were used. On the other hand, the allorestriction phenomenon was apparently abrogated when heavily modified ABA-PEC were employed: allogeneic as well as syngeneic ABA-PEC induced strong and comparable DTH responses. Even in this condition, xenogeneic (mouse) ABA-PEC were barely immunogeneic, On the basis of these observations, the cross-reactivity of Ia antigens in the conjunctive recognition of haptenic determinants by T cells is discussed.