Attempts to Transfer the Resistance of Schistosoma Mansoni-Infected and Irradiated Cercaria-Immunized Mice by Means of Parabiosis *

A major immunogen in Schistosoma mansoni infections is homologous to the heat-shock protein Hsp70.

“…Detection of serum antibodies to the S. mansoni 70,000 mol wt antigen by immunoprecipitation of 'SS-labeled polypeptides from S. mansoni adult worm RNA in vitro translation . Immunoprecipitates with S. mansoni-infected human serum (1), S. japonicuminfected human serum (2), uninfected human serum (3), S. haematobium-infected baboon serum (4), uninfected rat serum (5), chronically infected rat serum (6), mouse serum 6 wk after infection (25 cercariae) (7), chronically infected mouse serum (8), serum from mice vaccinated with four exposures of irradiated S. mansoni cercariae (9), and serum from mice immunized with lysates of Escherichia coli lysogenic with XcSMA-F4 (10) . (B) Relative abundance of a 70,000 mol wt protein in total protein extracts of adult worms (1) and cercariae (2).…”

Studies on the Mechanisms of Immunity in Human Schistosomiasis

“…Observations that there is a second phase of parasite attrition in chronically-infected mice, after the migration of schistosomula through the lungs (Smithers & Gammage 1980, Miller et al 1981, Blum & Cioli 1981, might suggest that surface antigens are expressed again during the later stages of the development of the schistosomulum. It has been suggested by several groups, however, that parasite attrition in such animals is attributable to a nonspecific trapping of schistosomula as a result of the formation of egg granulomas, rather than to a specific host protective response: Dean et al (1981), for example, have failed to demonstrate a transfer of immunity even after parabiosis. In contrast, the immunity that develops after immunization with irradiated cercariae can be transferred between parabiotic animals (Dean et al 1981): and in animals that have been immunized with irradiated cercariae, most of the parasite attrition that is observed after challenge occurs at the skin stage (Miller & Smithers 1981).…”

“…It has been suggested by several groups, however, that parasite attrition in such animals is attributable to a nonspecific trapping of schistosomula as a result of the formation of egg granulomas, rather than to a specific host protective response: Dean et al (1981), for example, have failed to demonstrate a transfer of immunity even after parabiosis. In contrast, the immunity that develops after immunization with irradiated cercariae can be transferred between parabiotic animals (Dean et al 1981): and in animals that have been immunized with irradiated cercariae, most of the parasite attrition that is observed after challenge occurs at the skin stage (Miller & Smithers 1981). Thus it seems likely that the antigens that elicit a specific protective immunity are expressed predominantly on the young, skinstage schistosomula.…”

Site potential for challenge attrition in mice, rats and guinea pigs vaccinated with irradiated cercariae of Schistosoma mansoni

“…Resistance to reinfection with Schistosorna mansoni develops in a variety of experimental hosts during the course of a chronic infection, or following vaccination with radiation attenuated cercariae or schistosomula (Smithers & Doenhoff 1982). Whilst the levels of protection developed in the two models are similar, the mechanisms responsible for measurable immunity are thought to differ (Smithers & Miller 1980), and, in vaccine-induced resistance, there is now convincing evidence for the role of specific immunological mechanisms (Dean, Bukowski & Clark 1981a, James, Labine & Sher 1981, Sher et al 1982, James & Sher 1983. In vitro cytotoxicity assays, used as probes of host resistance and parasite susceptibility, have shown that newly transformed schistosomula are susceptible to a variety of humoral and/or cellular effector mechanisms, but that older stages make use of sophisticated evasive stratagems to avoid immune attack (Smithers, McLaren & Ramalho-Pinto 1977, McLaren 1980, 1984, McLaren & Smithers 1982.…”