Naturally acquired humoral and cellular immune responses to Plasmodium vivax merozoite surface protein 9 in Northwestern Amazon individuals

Abstract

Antibody and T-cell reactivities to Plasmodium vivax merozoite surface protein-9 (PvMSP9) were evaluated in a cross-sectional study of individuals naturally exposed to malaria infections living in Ribeirinha, a native riverine community and in Colina, a transmigrant community, Rondonia, Brazil. The antibody responses to PvMSP9-RIRII and PvMSP9-Nt domains in Ribeirinha were higher compared with Colina and correlated with age and time of malaria exposure. IgG2 was most prevalent for PvMSP9-RII in both communities, and IgG1 was the predominant isotype for PvMSP9-Nt and PvMSP9-RIRII in Ribeirinha. IFN-γ and IL-4 predominated in Ribeirinha, while IFN-γ predominated in Colina. Variation in exposure to P. vivax likely accounts for the differences observed in cytokine and antibody levels between the two populations studied.

Immunological markers of Plasmodium vivax exposure and immunity: a systematic review and meta-analysis

“…In a Brazilian study in 2012, Lima-Junior et al [26] showed that IgG responders to PvMSP-9 RIRII had a 67% reduction in the odds of P. vivax infection, compared with non-responders, but in a 2008 study by these authors [24] in the same region, PvMSP-9 RIRII responders were found to have increased odds of P. vivax infection (OR = 2.64, Figure 7). Similar Figure 7 Forest plot of the association of PvMSP-9 IgG responses with P. vivax outcomes.…”

“…The full texts of these 162 studies were examined to determine whether they complied with eligibility criteria: 114 did not meet the inclusion criteria (see Additional file 3), 7 fulfilled the inclusion and quality criteria (Figure 1), and 41 studies potentially met inclusion and quality criteria. The authors of the 41 studies that potentially met inclusion and quality criteria were contacted, yielding a further 11 studies that met inclusion and quality criteria, providing a total of 18 studies that were included in the review [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] (Figure 1). Details of these 18 studies are shown in Table 1.…”

“…The studies described by Lima-Junior in 2008 and 2012 [24,26] were conducted in the same area, but the participants were different.…”

“…Cross-sectional studies Meta-analysis of three sets of cross-sectional data [24,26,36] showed that IgG responses to PvMSP-9 NT were associated with a 76% increase in odds of P. vivax infection compared with non-responders (pooled OR using random effects reOR = 1.76, 95% CI 0.95 to 3.25, Figure 7) suggesting that PvMSP-9 NT is a marker of exposure.…”

“…Cross-sectional studies Three sets of cross-sectional data investigated the association between IgG antibodies to a protein representing the two blocks of repeats in PvMSP-9 (PvMSP-9 RIRII ) and P. vivax infection [24,26,36]. In a Brazilian study in 2012, Lima-Junior et al [26] showed that IgG responders to PvMSP-9 RIRII had a 67% reduction in the odds of P. vivax infection, compared with non-responders, but in a 2008 study by these authors [24] in the same region, PvMSP-9 RIRII responders were found to have increased odds of P. vivax infection (OR = 2.64, Figure 7).…”