Changes in adult Nippostrongylus brasiliensis during the development of immunity to this nematode in rats

Abstract

Ultrastructural studies on adult Nippostrongylus brasiliensis removed at varying stages after infection from rats given a single dose of 2000 infective larvae have shown that changes in their cytology occur and that these can be correlated with the onset and development of immunity to this nematode in the host. The most noticeable changes are resorption of spermatozoa by the male reproductive tract, a drop in egg production, changes in the cytology of the intestinal cells, and the appearance of many large droplets, which look like droplets of lipid, in the cytoplasm of the hypodermis, muscles, excretory glands, reproductive system and the intestine. There are no obvious changes in the structure of the cuticle of the nematode during the course of infection. Possible reasons for the onset of these changes in the nematode are discussed.Much of this work was carried out during the tenure of grants from the U.S. Public Health Service (grant number AI 04275) and from the Agricultural Research Council while I was working at the Molteno Institute in Cambridge. I wish to thank the late Professor J. D. Boyd and Dr C. C. D. Shute of the Department of Anatomy, Cambridge, for permission to use the electron microscopes, Mrs B. Fisher for technical assistance and Mr Paul Rogers for assistance with the photography.