Catfish antibodies to blood group substances. I. Response of the Australian freshwater catfish, Tandanus tandanus (Mitchell), to the injection of human A, B and H secretor materials.

Injection of Australian freshwater catfish, (Mitchell), with human ABH secretor fluids mixed with adjuvant, resulted in the production by these fish of potent ABH specific haemagglutinating and precipitating antisera. No ABH haemagglutinins or precipitins were produced by catfish injected with non-secretor fluids. Fractionation of the agglutinins by absorption, together with immunodiffusion studies, revealed that in most cases, the predominant response was an anti-H response. However, in some fish injected with B or AB secretor salivas, high titres of cross-reacting A and B agglutinins were formed. The nature of the ABH agglutinin response in these fish is discussed with particular reference to three points. (1) The specificities of the ABH agglutinins formed. (2) The possibility that the variety and magnitude of the response are under some form of genetic control. (3) The possibility of the production in Australian freshwater catfish of anti-carbohydrate antibodies of limited heterogeneity.