Naturally acquired resistance to experimental infections of Schistosoma mansoni in the rhesus monkey (Macaca mulatta)

Abstract

In recent years there has been a steadily growing interest in the immunology of schistosomiasis. Much work has been carried out using a variety of experimental hosts and many attempts have been made to vaccinate these hosts against schistosomes, both by exposing them to irradiated cercariae and by injecting them with various antigens derived from the parasites. These attempts have been attended by varying degrees of success. The ultimate object of much of this work has been its possible application to the disease in man. We believe, however, that work of this kind cannot really be profitably undertaken unless there already exists a sound understanding of the basic host-parasite relations between the schistosomes and their hosts. This knowledge is essential in order to decide whether a finding in one host is likely to be applicable in others. With this idea in mind, we report here our findings on naturally acquired resistance to Schistosoma mansoni in the rhesus monkey.

Studies on the Mechanisms of Immunity in Human Schistosomiasis

“…The classical observation (section II), that adult worms are able to resist immune attack and continue to survive in hosts which are demonstrably immune to reinfection (Smithers & Terry 1965, leads to two questions. First, what are the mechanisms whereby the adult worm succeeds in avoiding a host immune response that is capable of damaging the young larvae of a challenge infection?…”

Elimination of Schistosoma mansoni Adult Worms by Rhesus Macaques: Basis for a Therapeutic Vaccine?

“…In this species, exposure to a moderate number of cercariae elicited protection against a challenge given four to five months later while the adult worms that engendered the immune response were apparently unaffected [9]. By analogy with tumor transplantation, the term concomitant immunity was proposed as an explanation [11].…”

Glycoconjugates in Host-Helminth Interactions

“…In the brown rat, which eliminates S. mansoni before patency, complement fixation, IgG2a and IgE levels, mast cell degranulation, and eosinophil-mediated antibody-dependent cellular cytotoxicity (ADCC) have been cited in protection (167–172). In rhesus macaques, another protective model for schistosomiasis where adult worms become attenuated in the weeks after reaching patency, IgG-mediated complement killing of schistosomules, and neutralization of adult worms have been demonstrated (173–175). Other animal models have shown that eosinophils, monocytes/macrophages, and neutrophils can mediate in vitro ADCC of various helminth larvae including S. mansoni , F. hepatica , and S. stercoralis (176–178).…”