Functionality of Toxoplasma gondii antibodies in a population of Beninese pregnant women exposed to malaria

Abstract Plasmodium falciparum and Toxoplasma gondii are two parasitic species affecting humans, that can lead to severe complications for the newborn when contracted during pregnancy. This study explores the cross-reactivity of antibodies specific to both pathogens in pregnant women belonging to population groups either exposed (Benin) or non-exposed (France) to malaria. The antibody response against antigens from both P. falciparum and T. gondii was analysed on plasma samples from the following population groups: PlasDCty (Benin, n = 29), CoaLa (Benin, n = 95) and TOXODIAG (France, n = 24). The antibody functionality was also assessed using P. falciparum in vitro Growth Inhibition Assay (GIA). The results demonstrated that toxoplasmosis seropositive women had higher levels of functional antibodies blocking P. falciparum growth in vitro than toxoplasmosis seronegative women particularly for those with an ongoing malaria infection. Interestingly, women with a concomitance of the two pathogens exhibited an even stronger functional antibody response against P. falciparum than women only seropositive for malaria (p = 0.001). These data suggest that the presence of T. gondii may influence the immune responses against malaria infection by enhancing growth inhibition activity of antibodies. This study provides insight into the immune dynamics of the co-infection by these two apicomplexans with potential implications for the development of cross-protective vaccines and therapies.