Recombinant Plasmodium vivax circumsporozoite surface protein allelic variants: antibody recognition by individuals from three communities in the Brazilian Amazon

Abstract

Circumsporozoite protein (CSP) variants of P. vivax , besides having variations in the protein repetitive portion, can differ from each other in aspects such as geographical distribution, intensity of transmission, vectorial competence and immune response. Such aspects must be considered to P. vivax vaccine development. Therefore, we evaluated the immunogenicity of novel recombinant proteins corresponding to each of the three P. vivax allelic variants (VK210, VK247 and P. vivax -like) and of the C-terminal region (shared by all PvCSP variants) in naturally malaria-exposed populations of Brazilian Amazon. Our results demonstrated that PvCSP-VK210 was the major target of humoral immune response in studied population, presenting higher frequency and magnitude of IgG response. The IgG subclass profile showed a prevalence of cytophilic antibodies (IgG1 and IgG3), that seem to have an essential role in protective immune response. Differently of PvCSP allelic variants, antibodies elicited against C-terminal region of protein did not correlate with epidemiological parameters, bringing additional evidence that humoral response against this protein region is not essential to protective immunity. Taken together, these findings increase the knowledge on serological response to distinct PvCSP allelic variants and may contribute to the development of a global and effective P. vivax vaccine.

A universal vaccine candidate against Plasmodium vivax malaria confers protective immunity against the three PvCSP alleles

“…Nevertheless, a significant proportion of this variant was found in P. vivax infections of patients from endemic areas of the Brazilian Amazon, as determined by molecular methods 17 – 19 . Consistent with these findings, Soares et al (2020) recently reported the high (~ 40–60%) prevalence of antibodies against P. vivax -like in patients from three communities in this region 55 . These results prompted us to propose that human-to-human transmission is very likely.…”

Structural basis of Plasmodium vivax inhibition by antibodies binding to the circumsporozoite protein repeats

“…Moreover, ~26% of the PvCSPvk210 central repeat region consists of charged residues, including arginine and aspartic acid residues. Both VK210 and VK247 strains have worldwide distribution (Cheng et al, 2013;Kain et al, 1992;Soares et al, 2020), and VK210 appears to be a major target of the humoral immune response in studied populations (González et al, 2001;Kim et al, 2010;Soares et al, 2020).…”

Structural basis of Plasmodium vivax inhibition by antibodies binding to the circumsporozoite protein repeats

“…Moreover, ~30% of the PvCSPvk210 central repeat region consists of charged residues, including arginine and aspartic acid residues. Both VK210 and VK247 strains have worldwide distribution (Cheng et al, 2013;Kain et al, 1992;Soares et al, 2020), and VK210 appears to be a major target of the humoral immune response in studied populations (González et al, 2001;Kim et al, 2010;Soares et al, 2020).…”