Effect of treating Schistosoma haematobium infection on Plasmodium falciparum-specific antibody responses

Abstract

Background: The overlapping geographical and socio-economic distribution of malaria and helminth infection has led to several studies investigating the immunological and pathological interactions of these parasites. This study focuses on the effect of treating schistosome infections on natural human immune responses directed against plasmodia merozoite surface proteins MSP-1 (DPKMWR, MSP1₁₉), and MSP-2 (CH150 and Dd2) which are potential vaccine candidates as well as crude malaria (schizont) and schistosome (whole worm homogenate) proteins.Methods: IgG1 and IgG3 antibody responses directed againstSchistosoma haematobiumcrude adult worm antigen (WWH) andPlasmodium falciparumantigens (merozoite surface proteins 1/2 and schizont extract), were measured by enzyme linked immunosorbent assay (ELISA) in 117 Zimbabweans (6–18 years old) exposed toS. haematobiumandP. falciparuminfection. These responses were measured before and after anti-helminth treatment with praziquantel to determine the effects of treatment on anti-plasmodial/schistosome responses.Results: There were no significant associations between antibody responses (IgG1/IgG3) directed againstP. falciparumand schistosomes before treatment. Six weeks after schistosome treatment there were significant changes in levels of IgG1 directed against schistosome crude antigens, plasmodia crude antigens, MSP-1₁₉, MSP-2 (Dd2), and in IgG3 directed against MSP-1₁₉. However, only changes in anti-schistosome IgG1 were attributable to the anti-helminth treatment.Conclusion: There was no association between anti-P. falciparumandS. haematobium antibodyresponses in this population andanti-helminth treatment affected only anti-schistosome responses and not responses against plasmodia crude antigens or MSP-1 and -2 vaccine candidates.