title: Interleukin-12 is capable of generating an antigen-specific Th1-type response in the presence of an ongoing infection-driven Th2-type response.
abstract: Previously we demonstrated that recombinant murine interleukin-12 (rmIL-12) administration can promote a primary Th1 response while suppressing the Th2 response in mice primed with 2,4, 6-trinitrophenyl-keyhole limpet hemocyanin (TNP-KLH). The present studies examined the capacity of rmIL-12 to drive a Th1 response to TNP-KLH in the presence of an ongoing Th2-mediated disease. To establish a distinct Th2 response, we used a murine model of leishmaniasis. Susceptible BALB/c mice produce a strong Th2 response when infected with Leishmania major and develop progressive visceral disease. On day 26 postinfection, when leishmaniasis was well established, groups of mice were immunized with TNP-KLH in the presence or absence of exogenous rmIL-12. Even in the presence of overt infection, TNP-KLH-plus-rmIL-12-immunized mice were still capable of generating KLH-specific gamma interferon (IFN-gamma) as well as corresponding TNP-specific immunoglobulin G2a (IgG2a) titers. In addition, the KLH-specific IL-4 was suppressed in infected mice immunized with rmIL-12. However, parasite-specific IL-4 and IgG1 production with a lack of parasite-specific IFN-gamma secretion were maintained in all infected groups of mice including those immunized with rmIL-12. These data show that despite the ongoing infection-driven Th2 response, rmIL-12 was capable of generating an antigen-specific Th1 response to an independent immunogen. Moreover, rmIL-12 administered with TNP-KLH late in infection did not alter the parasite-specific cytokine or antibody responses.
authors.affiliation: Genetics Institute, Inc., Department of Preclinical Biology Andover, Massachusetts 01810, USA. lschopf@lpsi.barc.usda.gov
authors.forename: L R
authors.initials: LR
authors.lastname: Schopf
authors.forename: J L
authors.initials: JL
authors.lastname: Bliss
authors.forename: L M
authors.initials: LM
authors.lastname: Lavigne
authors.forename: C L
authors.initials: CL
authors.lastname: Chung
authors.forename: S F
authors.initials: SF
authors.lastname: Wolf
authors.forename: J P
authors.initials: JP
authors.lastname: Sypek
mesh_terms: D000818:Animals; D016207:Cytokines / Q000096:biosynthesis; D005260:Female; D006241:Haptens; D006433:Hemocyanins / Q000276:immunology; D007074:Immunoglobulin G / Q000097:blood; D007371:Interferon-gamma / Q000096:biosynthesis; D018664:Interleukin-12 / Q000494:pharmacology*; D015847:Interleukin-4 / Q000096:biosynthesis; D018320:Leishmania major; D016773:Leishmaniasis, Cutaneous / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D011994:Recombinant Proteins / Q000494:pharmacology; D018417:Th1 Cells / Q000276:immunology*; D018418:Th2 Cells / Q000276:immunology*
chemical_list: D016207:Cytokines; D006241:Haptens; D007074:Immunoglobulin G; D011994:Recombinant Proteins; C054401:trinitrophenyl keyhole limpet hemocyanin; D018664:Interleukin-12; D015847:Interleukin-4; D007371:Interferon-gamma; D006433:Hemocyanins