Soluble antigens of Plasmodium gallinaceum

Antigens were isolated from plasma and serum of chickens acutely infected with Plasmodium gallinaceum. These antigens were allowed to react, in a gel precipitation test, with convalescent homologous sera and sera of human beings, monkeys and rats recovering from infections with P. falciparum, P. vivax, P. malariae, P. knowlesi, P. cynomolgi and P. berghei, respectively. A reaction occurred between these antigens and all sera tested. Antigens isolated from erythrocytes of infected chickens, however, reacted only with homologous sera in the above test. No non-specific precipitation reactions could be elicited in tests on a variety of sera. The tests included sera from persons infected with Treponema pallidum or (in one case) Babesia bovis, from cattle infected with Leptospira pomona, and from normal human, murine, avian, simian and bovine sera. Further studies with plasma or serum antigens from P. gallinaceum infections, for diagnosis of malaria, appear desirable.