title: Trypanosoma cruzi: protective immunity in mice immunized with paraflagellar rod proteins is associated with a T-helper type 1 response.
abstract: We have examined the ability of mice to survive a lethal challenge with the parasitic hemoflagellate, Trypanosoma cruzi, following immunization with paraflagellar rod proteins (PAR) 1 and 2 either alone or in combination with the following adjuvants: Freund's, alum, QS-21, Ribi-700, or IL-12. PAR administered subcutaneously (sc) in combination with Freund's or alum provided significant protection, 100 and 83%, respectively, against a T. cruzi challenge. In contrast, PAR in combination with QS-21, Ribi-700, IL-12, or Freund's administered intraperitoneally (ip) or PAR alone provide no protection against a challenge. PAR-specific serum antibody titers and isotype profiles for several of the immunization regimens were determined, and no positive correlation could be seen between a protective immune response and either antibody titer or the subclass of antibody induced. We also examined the ability of PAR to stimulate T cells from the spleen and lymph nodes of mice immunized with PAR in combination with Freund's (sc), Freund's (ip), alum, or Ribi-700. Each of the adjuvants strongly enhanced the ability of enriched T cells to proliferate in a PAR-specific fashion, suggesting no obvious correlation between PAR-specific T cell activation and protection. However, examination of the cytokine profiles of the stimulated T cell groups showed that the protective groups differed from the nonprotective groups. While all four groups showed low levels of IL-10, the Freund's (sc) and alum groups had higher levels of IFN-gamma and IL-2 than Freund's (ip) and Ribi-700 groups, and most strikingly, no IL-4 could be detected in either the Freund's (sc) or the alum group, in contrast to significant levels of IL-4 in both the Freund's (ip) and the Ribi-700 group. These findings indicate that protective immunity in mice immunized with PAR is associated with a Th1-type response.
authors.affiliation: Department of Molecular Biology and Biochemistry, University of California at Irvine 92697, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Miller
authors.forename: R A
authors.initials: RA
authors.lastname: Wrightsman
authors.forename: J E
authors.initials: JE
authors.lastname: Manning
mesh_terms: D000276:Adjuvants, Immunologic; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D014355:Chagas Disease / Q000276:immunology* / Q000469:parasitology; D005260:Female; D007110:Immunity, Active; D007115:Immunization Schedule; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D007371:Interferon-gamma / Q000096:biosynthesis; D007378:Interleukins / Q000096:biosynthesis; D051379:Mice; D008807:Mice, Inbred BALB C; D018512:Parasitemia / Q000276:immunology; D015800:Protozoan Proteins / Q000276:immunology*; D016052:Protozoan Vaccines / Q000276:immunology*; D018417:Th1 Cells / Q000276:immunology*; D014349:Trypanosoma cruzi / Q000276:immunology*; D014611:Vaccination
chemical_list: D000276:Adjuvants, Immunologic; D000913:Antibodies, Protozoan; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007378:Interleukins; D015800:Protozoan Proteins; D016052:Protozoan Vaccines; C045519:paraflagellar rod proteins, Trypanosoma brucei; C077477:PAR 2 protein, Trypanosoma cruzi; D007371:Interferon-gamma