Animal models for the study of immunity in human filariasis

Abstract

A major challenge to the development of vaccines against human lymphatic filariasis and onchocerciasis is to direct the immune response toward elimination of the early, prepothogenic larval stages and away from responses that mediate pathology. In this review, James Lok and David Abraham discuss the various animal models that have been used to investigate the pathways leading to immunity, immunologicol tolerance and chronic pathology in these diseases. Owing to the strict host specificities of the human-dwelling filariae, no single model serves to duplicate exactly all these aspects. Nevertheless, it has been possible to demonstrate a protective immune response invoked by and directed against incoming third-stage larvae of both lymphatic and skin-dwelling filariae. The fact that subsets of the sequelae of human filaraal infection can be duplicated in animal systems should also aid in unravelling the mechanisms determining the course of infection and in ensuring that vaccine candidates do not produce an inappropriate immunopothological response. A proposed scheme for using animal models in screening condidates for a vaccine against Onchocerca volvulus is presented.