ABSTRACT
This chapter focuses on the immunological aspects of resistance to filarial parasites. It shows that antifilarial vaccines could trigger some of the disease manifestations or exacerbate the clinical course of lymphatic filariasis and onchocerciasis in persons who subsequently become infected. Different filarial species are transmitted by different insect vectors and manifest characteristic tropisms for certain organs or tissues of their definitive host. Microfilariae of some species are enclosed in a multilayered sheath derived from the original eggshell, whereas larval and adult worm stages are bound by a typical nematode cuticle. Irradiated infective larvae have been successfully used to vaccinate various animals against several species of filariae. Thus, any vaccine against the microfilarial stage of Onchocerca must selectively elicit effector mechanisms that confer resistance without contributing to pathology. Skin, nodule, or uterine-derived microfilariae were all shown to bind eosinophils in vitro in the presence of sera from infected patients.
