Plasmodium falciparum merozoite surface antigen-specific cytophilic IgG and control of malaria infection in a Beninese birth cohort

• Published in: Malaria Journal
• Main Authors: Rafiou Adamou, Célia Dechavanne, Ibrahim Sadissou, Tania d’Almeida, Aziz Bouraima, Paulin Sonon, Roukiyath Amoussa, Gilles Cottrell, Agnès Le Port, Michael Theisen, Edmond J. Remarque, Shirley Longacre, Kabirou Moutairou, Achille Massougbodji, Adrian J. F. Luty, Gregory Nuel, Florence Migot-Nabias, Ambaliou Sanni, André Garcia, Jacqueline Milet, David Courtin
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2019
• Subjects: Plasmodium falciparum; Malaria; Cytophilic IgG; Merozoite vaccine candidate antigens; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1186/s12936-019-2831-x; https://doaj.org/article/78d39049ec404dcfa188a015552691cf

Abstract Background Substantial evidence indicates that cytophilic IgG responses to Plasmodium falciparum merozoite antigens play a role in protection from malaria. The specific targets mediating immunity remain unclear. Evaluating antibody responses in infants naturally-exposed to malaria will allow to better understand the establishment of anti-malarial immunity and to contribute to a vaccine development by identifying the most appropriate merozoite candidate antigens. Methods The study was based on parasitological and clinical active follow-up of infants from birth to 18 months of age conducted in the Tori Bossito area of southern Benin. For 399 infants, plasma levels of cytophilic IgG antibodies with specificity for five asexual stage malaria vaccine candidate antigens were determined by ELISA in infants’ peripheral blood at 6, 9, 12 and 15 months of age. Multivariate mixed logistic model was used to investigate the association between antibody levels and anti-malarial protection in the trimester following the IgG quantification. Moreover, the concentrations of merozoite antigen-specific IgG were compared between a group of infants apparently able to control asymptomatic malaria infection (CAIG) and a group of infants with no control of malaria infection (Control group (NCIG)). Protective effect of antibodies was also assessed after 15 months of malaria exposure with a Cox regression model adjusted on environmental risk. Results Cytophilic IgG responses to AMA1, MSP1, MSP2-3D7, MSP2-FC27, MSP3 and GLURP R2 were associated with increasing malarial infection risk in univariate analysis. The multivariate mixed model showed that IgG1 and IgG3 to AMA1 were associated with an increased risk of malarial infection. However infants from CAIG (n = 53) had significantly higher AMA1-, MSP2-FC27-, MSP3-specific IgG1 and AMA1-, MSP1-, MSP2-FC27-, MSP3 and GLURP-R2-specific IgG3 than those from NCIG (n = 183). The latter IgG responses were not associated with protection against clinical malaria in the whole cohort when ...