Familial correlation of immunoglobulin g subclass responses to Plasmodium falciparum antigens in Burkina Faso

Host genes are thought to determine the immune response to malaria infectio n and the outcome. Cytophilic antibodies have been associated with protecti on, whereas noncytophilic antibodies against the same epitopes may block th e protective activity of the protective ones. To assess the contribution of genetic factors to immunoglobulin G (IgG) subclass responses against conse rved epitopes and Plasmodium falciparum blood-stage extracts, we analyzed t he isotypic distribution of the IgG responses in 366 individuals living in two differently exposed areas in Burkina Faso. We used one-way analysis of variance and pairwise estimators to calculate sib-sib and parent-offspring correlation coefficients, respectively. Familial patterns of inheritance of IgG subclass responses to defined antigens and P. falciparum extracts appe ar to be similar in the two areas. We observed a sibling correlation for th e IgG, IgG1, IgG2, IgG3, and IgG4 responses directed against ring-infected- erythrocyte surface antigen, merozoite surface protein 1 (MSP-1), MSP-2, an d P. falciparum extract. Moreover, a parent-offspring correlation was found for several IgG subclass responses, including the IgG, IgG1, IgG2, IgG3, a nd IgG4 responses directed against conserved MSP-2 epitopes, Our results in dicated that the IgG subclass responses against P. falciparum blood-stage a ntigens are partly influenced by host genetic factors. The localization and identification of these genes may have implications for immunoepidemiology and vaccine development.