Resistance in murine schistosomiasis is contingent on activated IL-2 receptor-bearing L3T4+ lymphocytes, negatively regulated by Lyt-2+ cells, and uninfluenced by the presence of IL-4.
These studies assess the roles of subpopulations of T lymphocytes in inducing and modulating resistance to Schistosoma mansoni. C57BL/6 mice were depleted in vivo of L3T4+, Lyt-1+, Lyt-2+, IL-2R+ cells, or IL-4 by administration of appropriate mAb. Resistance and various correlative parameters of the immune response were studied in normal, depleted, and congenitally athymic mice. Depletion of T lymphocytes by anti-L3T4 or anti-IL-2R mAb reduced the development and expression of resistance, IgG2a and IgE antibody formation, and delayed type hypersensitivity reactivity against schistosome Ag. Depletion with anti-IL-4 antibody led to profound suppression of IgE-eosinophil-mediated antibody-dependent cell-mediated cytotoxicity and passive cutaneous anaphylaxis responses against the parasite and no effect on IgG2a antibody, Ag-mediated blast transformation, or resistance. Depletion of Lyt-2+ cells produced augmented development and expression of resistance and an increase in the immunological parameters of anti-schistosome reactivity. These studies suggest that protective immunity to S. mansoni in mice, induced by irradiated cercariae, is dependent on L3T4+, IL-2R+ lymphocytes and negatively regulated by Lyt-2+ cells. IL-4 does not appear to be essential for the development of resistance but is essential for the IgE response to the parasite.
Phillips
S M
SM
Allergy and Immunology Section, University of Pennsylvania School of Medicine, Philadelphia 19104.
Lin
J J
JJ
Galal
N
N
Tung
A S
AS
Linette
G P
GP
Perrin
P J
PJ
D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte; D016827:CD8 Antigens; D007113:Immunity, Innate / Q000276:immunology; D007114:Immunization; D007156:Immunologic Memory / Q000276:immunology; D015847:Interleukin-4 / Q000502:physiology; D008212:Lymphocyte Depletion; D051379:Mice; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D015375:Receptors, Interleukin-2; D012555:Schistosomiasis mansoni / Q000276:immunology*; D016176:T-Lymphocyte Subsets / Q000276:immunology*
D000945:Antigens, Differentiation, T-Lymphocyte; D016827:CD8 Antigens; D015375:Receptors, Interleukin-2; D015847:Interleukin-4