Nitric oxide (NO) is an important effector molecule involved in
immune regulation and defense. NO produced by cytokine-activated
macrophages was reported to be cytotoxic against the helminth
Schistosoma mansoni. Identification and characterization of
S. mansoni antigens that can provide protective immunity is
crucial for understanding the complex immunoregulatory events that
modulate the immune response in schistosomiasis. It is, then,
essential to have available defined, purified parasite antigens.
Previous work by our laboratory identified a fraction of S.
mansoni soluble adult worm antigenic preparation (SWAP), named
PIII, able to elicit significant in vitro cell proliferation
and at the same time lower in vitro and in vivo
granuloma formation when compared either to SEA (soluble egg antigen)
or to SWAP. In the present work we report the effect of different
in vivo trials with mice on their spleen cells ability to
produce NO. We demonstrate that PIII-immunization is able to
significantly increase NO production by spleen cells after in
vitro stimulation with LPS. These data suggest a possible role for
NO on the protective immunity induced by PIII.
