The Plasmodium falciparum merozoite surface protein-1 19 KD antibody response in the Peruvian Amazon predominantly targets the non-allele specific, shared sites of this antigen

• Published in: Malaria Journal
• Main Authors: Silva Claudia, Clark Eva H, Sutton Patrick L, Branch OraLee H
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2010
• Subjects: Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1186/1475-2875-9-3; https://doaj.org/article/1f0be655bb4a456fbf38cf3c8f377a48

Abstract Background Plasmodium falciparum re-emerged in Iquitos, Peru in 1994 and is now hypoendemic (< 0.5 infections/person/year). Purportedly non-immune individuals with discrete (non-overlapping) P. falciparum infections can be followed using this population dynamic. Previous work demonstrated a strong association between this population's antibody response to Pf MSP1-19KD and protection against febrile illness and parasitaemia. Therefore, some selection for Pf MSP1-19KD allelic diversity would be expected if the protection is to allele-specific sites of Pf MSP1-19KD. Here, the potential for allele-specific polymorphisms in this population is investigated, and the allele-specificity of antibody responses to Pf MSP1-19KD are determined. Methods The 42KD region in Pf MSP1 was genotyped from 160 individual infections collected between 2003 and 2007. Additionally, the polymorphic block 2 region of Pfmsp1 ( Pfmsp1 -B2) was genotyped in 781 infection-months to provide a baseline for population-level diversity. To test whether Pf MSP1-19KD genetic diversity had any impact on antibody responses, ELISAs testing IgG antibody response were performed on individuals using all four allele-types of Pf MSP1-19KD. An antibody depletion ELISA was used to test the ability of antibodies to cross-react between allele-types. Results Despite increased diversity in Pfmsp1 -B2, limited diversity within Pfmsp1 -42KD was observed. All 160 infections genotyped were Mad20-like at the Pfmsp1 -33KD locus. In the Pfmsp1 -19KD locus, 159 (99.4%) were the Q-KSNG-F haplotype and 1 (0.6%) was the E-KSNG-L haplotype. Antibody responses in 105 individuals showed that Q-KNG and Q-TSR alleles generated the strongest immune responses, while Q-KNG and E-KNG responses were more concordant with each other than with those from Q-TSR and E-TSR, and vice versa. The immuno-depletion ELISAs showed all samples responded to the antigenic sites shared amongst all allelic forms of Pf MSP1-19KD. Conclusions A non-allele specific antibody response in Pf ...