Differential recognition patterns of Schistosoma haematobium adult worm antigens by the human antibodies IgA, IgE, IgG1 and IgG4

Abstract

Abstract Schistosoma haematobium antigen recognition profiles of the human isotypes IgA, IgE, IgG1 and IgG4 were compared by image analysis of western blots. Adult worm antigens separated by 2-dimensional gel electrophoresis were probed with pooled sera from Zimbabweans resident in a S. haematobium endemic area, followed by identification of individual antigenic parasite proteins using mass spectrometry. Overall, IgG1 reacted with the largest number of antigens, followed by IgE and IgA which detected the same number, while IgG4 detected the fewest antigens. IgE recognised all the antigens reactive with IgG4 as well as an additional four antigens; an isoform of 28kDaGST, phosphoglycerate kinase, actin 1 and calreticulin. IgG1 additionally recognised fatty acid binding protein, triose-phosphate isomerase, and heat shock protein 70, which were not recognised by IgA. Recognition patterns varied between some isoforms e.g. the 2 fructose 1-6-bis-phosphate aldolase isoforms differentially recognised by IgA and IgG1. Although the majority of S. haematobium adult worm antigens are recognised by all the four isotypes there are clear restrictions in antibody recognition for some antigens. This may partly explain differences observed in isotype dynamics at a population level. Differential recognition patterns for some isoforms indicated in the study have potential importance for vaccine developmen