Immunization of Baboons with Schistosoma mansoni Cercariae Attenuated by Gamma Irradiation

Abstract

Studies on the efficacy of a vaccine against schistosomiasis in young baboons (Papio anubis) disclosed that immunization with Schistosoma mansoni cercariae attenuated by gamma irradiation induced significant protection against subsequent infection with normal, viable S. mansoni cercariae. Such immunization resulted in reduced worm burdens (70 percent) and egg excretion rates (82 percent). These results support immunization as a potential method for schistosomiasis control.

Schistosoma mansoni egg granuloma size reduction in challenged baboons after vaccination with irradiated cryopreserved schistosomula.

“…Baboons are excellent experimental models for human schistosomiasis (14)(15)(16)(17), including vaccine testing (18)(19)(20)(21). We found a reduction in the size of hepatic and intestinal granulomas in baboons infected after having been vaccinated, yet these smaller granulomas appeared to be fully effective in sequestering toxic egg products in the liver.…”

Acute schistosomiasis mansoni in the baboon Papio anubis gives rise to goblet-cell hyperplasia and villus atrophy that are modulated by an irradiated cercarial vaccine

“…Our study shows that subtle lesions, including goblet-cell hyperplasia and villus atrophy, occur in the intestines of baboons infected by S. mansoni. The presence of these lesions could explain at least in part the clinical signs associated with acute schistosomiasis mansoni in the baboon, including malaise, anorexia, diarrhea, dysentery, and, occasionally, death (Stek et al 1981). The absorption of glucose and sorbital has also been shown to be impaired in S. mansoni-infected mice, probably due to apparent reduction of the total intestinal absorptive area (Vengessa and Leese 1979).…”

Schistosoma mansoni TOR is a tetraspanning orphan receptor on the parasite surface

“…There are efforts to develop a vaccine against schistosomiasis. Radio-attenuated cercariae induced a high level of protection in animal models (Minard et al 1978 ;Stek et al 1981) and naturally resistant population groups exist (Correa-Oliveira et al 1989, which suggests that development of an effective vaccine is likely to be possible (McManus and Loukas, 2008). There is a list of recombinant proteins that correlate with resistance in human studies and/or have shown efficacy in animal models (McManus and Loukas, 2008).…”