Immunoregulation in experimental schistosomiasis. II. Soluble egg antigen-induced chronic spleen cell augmentation of baseline lymphocyte reactivity.

Spleen cells from mice harboring infections of Schistosoma mansoni for 20 weeks exposed to Con A or to soluble schistosome egg antigenic preparation (SEA), treated with Mitomycin C (Mc), and cocultured with spleen cells from either normal or infected mice caused an augmented baseline [3H]TdR incorporation by the otherwise unstimulated responder cells. This regulation required an in vitro induction phase. SEA-exposed, Mc-treated normal spleen cells had no effect on responder cell cultures. SEA-stimulated, Mc-treated chronic spleen cell augmentation was effective on responder cell populations from either normal mice or mice infected with S. mansoni for 8 weeks. Augmentation was most pronounced when assayed on cells from infected mice assayed over a 5-day incubation. In addition, it is demonstrated that these Con A- and SEA-elicited activities are mediated by soluble mediators which lack H-2 restriction.