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Exp Parasitol. 1996 Nov;84(2):264-73.

H. polygyrus: B7-independence of the secondary type 2 response.

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Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814, USA.


The gastrointestinal nematode parasite, Heligmosomoides polygyrus, has been used extensively in experimental studies of host immunity. The pronounced type 2 primary immune response to H. polygyrus is associated with elevated CD4+, TCR-alpha/beta + T cell IL-4 production and elevated serum IgE levels that are blocked by inhibiting CD28/ CTLA4-B7 interactions following in vivo administration of the chimeric fusion protein, CTLA4Ig. In the present study, we have examined the in vivo effects of blocking CTLA4Ig ligands on the secondary type 2 mucosal host protective immune response to this parasite. Our results show that although CD4+, TCR-alpha/beta + cells remain the primary source of elevated IL-4 during the secondary response, the protective immune response and the effector cell activity associated with it is B7-independent as CTLA4Ig administration at the time of challenge does not block (1) elevations in T cell IL-4 gene expression or protein secretion; (2) elevations in serum IgE levels, mucosal mastocytosis, or eosinophilia; or (3) host protection, as measured by adult worm burden and fecundity. These findings suggest that memory T helper cells do not require CD28-B7 interactions for their activation to effector cells that can mediate a host protective type 2 immune response.

[Indexed for MEDLINE]

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