Antibody responses within two leading Plasmodium vivax vaccine candidate antigens in three geographically diverse malaria-endemic regions of India (original) (raw)
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The American journal of tropical medicine and hygiene, 2006
The antibody responses to the apical membrane antigen 1 of the Plasmodium vivax (PvAMA-1) were investigated in subjects living in areas of Brazil with different levels of malaria transmission. The prevalence and the levels of IgG to PvAMA-1 increased with the time of exposure. The frequency of a positive response and the mean IgG level were higher in areas where malaria prevalence was more intense, especially among non-infected subjects exposed to moderate transmission over a period of 20 years. The proportions and levels of IgG1and IgG3 isotypes were significantly higher among those subjects with long-term exposure. Antibodies, mainly IgG1, to PvAMA-1 persisted for seven years among subjects briefly exposed to malaria in an outbreak outside the Brazilian malaria-endemic area. These data show the highly immunogenic properties of PvAMA-1 and emphasize its possible use as a malaria vaccine candidate.
The American journal of tropical medicine and hygiene, 2008
Plasmodium vivax is the second most prevalent global Plasmodium species causing malaria after P. falciparum. These two Plasmodium spp. co-exist in most endemic areas, apart from west and central Africa, which has only P. falciparum. However, southeastern Turkey is one of the exceptional regions with the sole presence of P. vivax infection, where a thorough epidemiologic survey has not been performed. Here, we report for the first time the identification of naturally acquired antibodies against the 19-kd C-terminal region of the merozoite surface protein-1 of P. vivax (PvMSP1(19)), using ELISA, from residents in the Sanliurfa region of southeastern Turkey. Among the 82 samples from patients with patent P. vivax malaria, 85% of the individuals were sero-reactive to PvMSP1(19). Particularly, 69.5% of the subjects were positive for IgM, 53.6% were positive for IgG (predominantly IgG1 and IgG3), and 7.3% were positive for IgA.