Ablation of eosinophil and IgE responses with anti-IL-5 or anti-IL-4 antibodies fails to affect immunity against Schistosoma mansoni in the mouse
Sher, A.; Coffman, R.L.; Hieny, S.; Cheever, A.W.
Journal of Immunology 145(11): 3911-3916
1990
ISSN/ISBN: 0022-1767 PMID: 2123226 Document Number: 348258
To investigate the role of anaphylactic immune responses in protective immunity against schistosomiasis, mice vaccinated with irradiated cercariae of S. mansoni (NMRI strain) were treated with neutralizing MAbs against either IL-5 or IL-4 before and during challenge infection. Anti-IL-5-treated vaccinated mice showed a complete ablation of circulating as well as tissue eosinophils, present in inflammatory reactions to migrating schistosomula in the skin and lungs, but nevertheless eliminated challenge infections as effectively as vaccinated animals treated with a control MAb. Similarly, treatment of vaccinated mice with an anti-IL-4 MAb markedly reduced serum IgE although failing to diminish immunity. The effect of anti-IL-5 mediated eosinophil depletion was also assessed in a 2nd model in which resistance is induced by concomitant chronic infection. Again, normal, unaltered protection was observed in the absence of circulating and tissue eosinophils. In contrast to the above findings, treatment with anti-IFN- gamma was found to cause a partial depletion of immunity in vaccinated mice while, paradoxically, increasing the numbers of inflammatory reactions against invading schistosomula in the lungs. These observations argue against a requirement for either eosinophils or IgE in the anti-schistosome immunity induced by vaccination with irradiated cercariae, or for eosinophils in the resistance resulting from previous infection in mice, and support previous data suggesting a role for an IFN- gamma dependent cell-mediated effector mechanism in vaccine-induced resistance.