Development of Immunity in Natural Plasmodium falciparum Malaria: Antibodies to the Falciparum Sporozoite Vaccine 1 Antigen (R32tet32)

摘要

Antibodies that reacted with a candidate sporozoite vaccine antigen (R32tet32) were found in 20 of 21 patients treated for acute infection with Plasmodium falciparum and monitored longitudinally over 67 days. R32tet32 contains 32 tandem copies of a tetrapeptide sequence that constitutes the immunodominant epitope of the circumsporozoite surface protein. The magnitude of the antibody response varied considerably among individuals and appeared to be independent of the number of previous clinical infections. Recrudescence of infection or infection with Plasmodium vivax had no demonstrable effect on antibody levels, although reinfection with P. falciparum produced a rapid rise in antibody titer. Antibody levels were observed to decline rapidly after treatment of clinical infection with mefloquine. We report here on the occurrence of antibodies to R32tet32 and their quantitative and temporal characteristics in plasma from individuals naturally infected with P. falciparum malaria. Our observations suggest that anti-R32tet32 antibodies were not protective against naturally occurring malaria in Thailand. It further appears that immunosuppression associated with acute infection acted to prevent development of an optimal immune response. Keywords: Antimalarials, Vaccines, Reprints. (kt)