IgE sequences in individuals living in an area of endemic parasitism show little mutational evidence of antigen selection

Abstract

Patterns of somatic mutation in IgE genes from allergic individuals have been a focus of study for many years, but IgE sequences have never been reported from parasitized individuals. To study the role of antigen selection in the evolution of the anti-parasite response, we therefore generated 118 IgE sequences from donors living in Papua New Guinea (PNG), an area of endemic parasitism. For comparison, we also generated IgG1, IgG2, IgG3 and IgG4 sequences from these donors, as well as IgG1 sequences from Australian donors. IgE sequences had, on average, 23.0 mutations. PNG IgG sequences had average mutation levels that varied from 17.7 (IgG3) to 27.1 (IgG4). Mean mutation levels correlated significantly with the position of their genes in the constant region gene locus (IgG3 <0.01). The anti-parasite IgE response therefore has the reduced evidence of antigen selection that has previously been reported in studies of IgE sequences from allergic individuals. © 2011 The Authors. Scandinavian Journal of Immunology © 2011 Blackwell Publishing Ltd.