Protective immunity induced in squirrel monkeys with recombinant apical membrane antigen-1 of Plasmodium fragile

W. E. Collins, D. Pye, P. E. Crewther, K. L. Vandenberg, G. G. Galland, A. J. Sulzer, D. J. Kemp, S. J. Edwards, R. L. Coppel, J. S. Sullivan, C. L. Morris, R. F. Anders

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Abstract

Saimiri sciureus boliviensis monkeys were immunized with the Plasmodium fragile form of the merozoite apical membrane antigen-1 produced using the baculovirus expression system and combined with Montanide 1SA 720 adjuvant. Following three immunizations, monkeys were challenged with 10,000 P. fragile trophozoite parasites. Antibody titers determined by fluorescence microscopy indicated an enhanced response following the second immunization. Four of five control animals had parasite counts > 5% 18-26 days following challenge. Four of five immunized monkeys had reduced levels of maximum parasitemia or delays in accumulated parasite counts, suggestive of protection. Rechallenge of the animals with P. falciparum resulted in three of four adjuvant control animals developing patent parasitemia whereas none of five immunized animals were infected, suggesting some level of heterologous protection.

Original languageEnglish
Pages (from-to)711-719
Number of pages9
JournalThe American Journal of Tropical Medicine and Hygiene
Volume51
Issue number6
Publication statusPublished - 1 Dec 1994
Externally publishedYes

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