Susceptibility to Autoimmune Responses after Parasite Removal in a Wild Peromyscus Population

Abstract

The vertebrate immune system has evolved to produce efficient responses to clear infection. Despite strong selective forces against deleterious immunity, autoimmunity is nonetheless prevalent in human and other mammalian populations. However, immune function of wild animals may differ from that of domesticated and laboratory bred animals and thus, susceptibility to autoimmunity must be accounted for within the context of natural environments. Wild animals particularly tend to suffer from heavy parasite burdens which can have consequences for host immune function and fitness. The aim of this study was to investigate how clearing parasites influences the autoimmune status of individuals within a wild mouse population. A wild population of Peromyscus leucopus and P. maniculatus co-infected with diverse intestinal helminths and ectoparasites was treated with an antihelmintic and an acaricide in order to reduce parasite burden. Blood serum samples from each mouse were assayed for antinuclear antibody (ANA) and total IgG using a sandwich ELISA technique. In accordance with my hypothesis, positive correlations of total IgG and ANA concentrations were observed. Despite an observed effect of antihelmintic treatment influencing ANA concentration variance among recaptured Peromyscus, further research is needed to fully elucidate the effect of helminth clearance on susceptibility to autoimmunity. This study suggests that maintaining endemic populations of intestinal parasites may help to promote the immunological fitness of wild mice.