Plasmodium vivax Duffy binding protein: baseline antibody responses and parasite polymorphisms in a well‐consolidated settlement of the Amazon Region

Abstract

Abstractobjective To investigate risk factors associated with the acquisition of antibodies against Plasmodium vivax Duffy binding protein (PvDBP) -a leading malaria vaccine candidate -in a well-consolidated agricultural settlement of the Brazilian Amazon Region and to determine the sequence diversity of the PvDBP ligand domain (DBP II ) within the local malaria parasite population.methods Demographic, epidemiological and clinical data were collected from 541 volunteers using a structured questionnaire. Malaria parasites were detected by conventional microscopy and PCR, and blood collection was used for antibody assays and molecular characterisation of DBP II .results The frequency of malaria infection was 7% (6% for P. vivax and 1% for P. falciparum), with malaria cases clustered near mosquito breeding sites. Nearly 50% of settlers had anti-PvDBP IgG antibodies, as detected by enzyme-linked immunosorbent assay (ELISA) with subject's age being the only strong predictor of seropositivity to PvDBP. Unexpectedly, low levels of DBP II diversity were found within the local malaria parasites, suggesting the existence of low gene flow between P. vivax populations, probably due to the relative isolation of the studied settlement.conclusion The recognition of PvDBP by a significant proportion of the community, associated with low levels of DBP II diversity among local P. vivax, reinforces the variety of malaria transmission patterns in communities from frontier settlements. Such studies should provide baseline information for antimalarial vaccines now in development.

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

“…In a cross-sectional study, Kano et al [23] found no evidence for any association between IgG responses to PvDBPII-IV Sal 1 and P. vivax infection. One study by Souza-Silva et al provided data from two cross-sectional surveys conducted in the same study site in Brazil [29].…”

“…The association of antibodies to PvDBP region II-IV (PvDBPII-IV) and P. vivax infection was examined in one cross-sectional study [23] and one cohort study that also provided two sets of cross-sectional data [29]. In a cross-sectional study, Kano et al [23] found no evidence for any association between IgG responses to PvDBPII-IV Sal 1 and P. vivax infection.…”

“…Four cross-sectional studies (providing five sets of data) investigated the association between IgG responders to PvMSP-1 19 and P. vivax infection (Figure 4) [22,23,26,39]. Meta-analysis revealed significant heterogeneity between studies (I 2 = 73.8%, P = 0.004), so a pooled estimate was not reported.…”

“…A total of eight studies investigated responses to PvMSP-1 19 and P. vivax outcomes [22,23,26,27,32,34,39,40].…”

“…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.…”