Serum samples from 11 patients having past experience with malaria were tested using the fluorescent antibody (FA) technique against antigens of Plasmodium falciparum, P. malariae, P. vivax, P. fieldi, P. gonderi, P. inui, P. coatneyi, P. knowlesi, P. cynomolgi bastianellii, and P. brasilianum.
The FA reactions showed that experience with P. falciparum and P. malariae produced response to all the Plasmodium antigens tested. In patients having experienced only P. falciparum cross-reactions were highest with P. fieldi, whereas in those having experienced only P. malariae cross-reactions were high not only with P. brasilianum but also with P. fieldi.
Patients having multiple recent experiences with these two malarias continued to cross-reacted significantly with both P. fieldi and P. brasilianum.
Address: Assistant Chief, Laboratory of Parasite Chemotherapy, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20014.