Immunization with Ascaris suum extract impairs T cell functions in mice.
The effect of an Ascaris suum extract (Asc) on several T cell functions was studied in mice immunized with Asc and ovalbumin (OA) in complete Freund's adjuvant. Delayed-type hypersensitivity reactions following challenge with aggregated OA were markedly diminished in mice injected with OA plus a high dose of Asc compared to OA-immunized animals. Proliferation and IL-2, IFN-gamma, IL-4, and IL-10 production in OA-stimulated lymph node cells from the OA + Asc-immunized group were also inhibited. Titration of anti-OA antibodies also showed suppression of IgG1, IgG2a, and IgE isotypes in the animals injected simultaneously with the extract. The degree of suppression induced by Asc on OA-specific cell-mediated responses was dose dependent. The profile of cytokines synthesized in response to Asc also changed depending on the injected dose. IL-4 and IL-10 were mainly produced in response to high doses, whereas IL-2 and IFN-gamma were greatly enhanced at a low dose of Asc. These findings indicate that the A. suum extract may impair crucial T cell functions for cell-mediated as well as humoral immune responses to other antigens through the induction of a predominantly Th2-like response.
Ferreira
A P
AP
Department of Immunology, University of São Paulo, Brazil.
Faquim
E S
ES
Abrahamsohn
I A
IA
Macedo
M S
MS
D000818:Animals; D000909:Antibodies, Helminth / Q000276:immunology; D000917:Antibody Formation; D000947:Antigens, Helminth / Q000276:immunology; D017165:Ascaris suum / Q000276:immunology*; D004306:Dose-Response Relationship, Immunologic; D006967:Hypersensitivity / Q000276:immunology*; D006968:Hypersensitivity, Delayed / Q000276:immunology; D007132:Immunoglobulin Isotypes / Q000276:immunology; D007371:Interferon-gamma / Q000096:biosynthesis; D016753:Interleukin-10 / Q000096:biosynthesis; D007376:Interleukin-2 / Q000096:biosynthesis; D015847:Interleukin-4 / Q000096:biosynthesis; D008213:Lymphocyte Activation; D008297:Male; D051379:Mice; D008811:Mice, Inbred DBA; D010047:Ovalbumin / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
D000909:Antibodies, Helminth; D000947:Antigens, Helminth; D007132:Immunoglobulin Isotypes; D007376:Interleukin-2; D016753:Interleukin-10; D015847:Interleukin-4; D007371:Interferon-gamma; D010047:Ovalbumin