Additional preliminary studies of the feline major histocompatibility complex

The authors' preliminary studies of the feline histocompatibility system have indicated that relatively little or no polymorphism can be demonstrated by standard techniques used in other mammalian species. Although strong proliferative responses of feline lymphocytes can be elicited by the mitogen Con-A, only very weak proliferative responses are elicited in mixed lymphocyte cultures even between cells from cats of different breeds. Cats fail to make lymphocytotoxic antibodies to either T cells or non-T-cells after repeated immunization by pregnancy or blood transfusion. Although cats immunized repeatedly by subcutaneous immunization with mononuclear cells do produce lymphocytotoxic antibodies, these antibodies show little polymorphism, reacting with all other cat cells except those of the immunizing donor. They also fail to block the (weak) mixed lymphocyte culture responses to cells from the donor cat. The authors' additional preliminary efforts to demonstrate the existence of a (polymorphic) feline major histocompatibility complex will be described in this article.