Protective killed Leptospira borgpetersenii vaccine induces potent Th1 immunity comprising responses by CD4 and gammadelta T lymphocytes.
Leptospira borgpetersenii serovar hardjo is the most common cause of bovine leptospirosis and also causes zoonotic infections of humans. A protective killed vaccine against serovar hardjo was shown to induce strong antigen-specific proliferative responses by peripheral blood mononuclear cells (PBMC) from vaccinated cattle by 2 months after the first dose of vaccine. This response was absent from nonvaccinated control cattle. The mean response peaked by 2 months after completion of the two-dose vaccination regimen, and substantial proliferation was measured in in vitro cultures throughout the 7 months of the study period. Variations in magnitude of the response occurred among the vaccinated animals, but by 7 months postvaccination there was a substantial antigen-specific response with PBMC from all vaccinated animals. Up to one-third of the PBMC from vaccinated animals produced gamma interferon (IFN-gamma) after 7 days in culture with antigen, as ascertained by flow cytometric analysis, and significant levels of IFN-gamma were measured in culture supernatants by enzyme-linked immunosorbent assay. Two-color immunofluorescence revealed that one-third of the IFN-gamma-producing cells were gammadelta T cells, with the remaining cells being CD4(+) T cells. The significance of this study is the very potent Th1-type immune response induced and sustained following vaccination with a killed bacterial vaccine adjuvanted with aluminum hydroxide and the involvement of gammadelta T cells in the response. Moreover, induction of this Th1-type cellular immune response is associated with the protection afforded by the bovine leptospiral vaccine against L. borgpetersenii serovar hardjo.
Naiman
B M
BM
Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, Massachusetts 01003, USA.
Alt
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D
Bolin
C A
CA
Zuerner
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Baldwin
C L
CL
D000818:Animals; D001428:Bacterial Vaccines / Q000276:immunology*; D002417:Cattle; D002418:Cattle Diseases / Q000517:prevention & control*; D005260:Female; D007111:Immunity, Cellular; D007371:Interferon-gamma / Q000096:biosynthesis; D007922:Leptospirosis / Q000517:prevention & control / Q000662:veterinary*; D008213:Lymphocyte Activation; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000276:immunology; D016176:T-Lymphocyte Subsets; D018417:Th1 Cells / Q000276:immunology*; D014611:Vaccination; D015164:Vaccines, Inactivated / Q000276:immunology
D001428:Bacterial Vaccines; D016692:Receptors, Antigen, T-Cell, gamma-delta; D015164:Vaccines, Inactivated; D007371:Interferon-gamma