Induction of protective immunity against Schistosoma mansoni by a nonliving vaccine. III. Correlation of resistance with induction of activated larvacidal macrophages
James, S.L.
Journal of Immunology 136(10): 3872-3877
1986
ISSN/ISBN: 0022-1767 PMID: 3084646 Document Number: 274643
Mice protected against Schistosoma mansoni infection by intradermal (i.d.) immunization with nonliving larval or adult worm antigens plus bacterial adjuvant developed 24-hr skin test responsiveness to schistosome antigens with the histologic features of delayed hypersensitivity. Intraperitoneal antigen injection elicited a mononuclear cell-enriched exudative population containing macrophages activated for direct cytotoxicity against schistosomula and tumor cell targets. This was likely to be due to in vivo exposure to macrophage-activating lymphokines, since these cells were unresponsive to further lymphokine stimulation in vitro and splenocytes from immunized mice reacted to specific in vitro antigen challenge by production of lympholines capable of conferring larvacidal activity upon control macrophages. In contrast, mice treated with schistosome antigens by i.v. injection, which were not protected against challenge infection, failed to develop delayed hypersensitivity or activated macrophages in response to specific antigen challenge in vivo, and the titers of macrophage-activating lymphokine produced by in vitro anti-stimulated splenocytes from these mice were threefold or fourfold lower than those produced by cells from animals immunized by the i.d. route. Thus, sensitization for cell-mediated immune response including lympholine production and macrophge activation correlated with induction of resistance to S. mansoni in this model of vaccination.