In vivolocalization of antibodies raised againstEimeria maximawall forming bodies during sexual intracellular development

Abstract

SUMMARYApicomplexan parasites cause devastating diseases in humans and livestock. Previously we demonstrated that antibodies targeting transmissible forms of the apicomplexan parasite,Eimeria, are effective at reducing parasite shedding thus preventing the transmission of the disease. However, the mechanisms responsible have not been fully defined. Moreover, there is no direct evidence that the parasite-specific IgG antibodies can reach the parasite developing in the enterocytes of the infected chicken host. This study summarizes our efforts using host immunity, parasite proteomics and 3D microscopy to provide a step forward in our understanding of how this immune response works.Eimeria maximais an important pathogen of poultry and used as a surrogate for a number of human pathogens includingToxoplasmaandPlasmodium. Our studies demonstrate that immunization with the purified wall forming bodies (WFBs) results in a production of parasite-specific IgG antibodies, which have the ability to reachin situgametocytes in the intestinal lumen and permeate the enterocyte/parasite membranes in order to bind to the cytoplasmic Type 1 and Type 2 WFBs. This raises the intriguing possibility that via this process antibodies block the development ofEimeria maxima in vivo.