title: Human T cell responses induced by vaccination with Mycobacterium bovis bacillus Calmette-Guérin.
abstract: Many aspects of the widely used bacillus Calmette-Guérin (BCG) vaccine against tuberculosis are still the subject of controversy. There is a huge variation in efficacy from one clinical trial to another and no relationship between vaccine-induced skin test conversion and subsequent protection. We have studied in vitro cell-mediated immune responses primed by BCG vaccination in 22 healthy Danish donors with different levels of in vitro purified protein derivative (PPD) reactivity before vaccination. The study demonstrated a markedly different development of reactivity to mycobacterial Ags depending on the prevaccination sensitivity to PPD. Previously sensitized donors mounted a potent and highly accelerated recall response within the first week of BCG vaccination. Nonsensitized donors, in contrast, exhibited a gradually increasing responsiveness to mycobacterial Ags, reaching maximal levels between day 56 and 365 postvaccination. The recognition of different classes of Ags were induced in a stepwise manner: culture filtrate Ags were recognized 1 wk postvaccination followed by cell wall, membrane, and the cytosolic Ag fraction. The T cell response primed by BCG vaccination was characterized as a CD4 response with a Th1-like cytokine pattern and substantial levels of Ag-specific cytotoxicity. The specificity of the T cell response generated was broad and directed to a range of culture filtrate Ag fractions. The study shows that BCG vaccination of previously nonsensitized donors can provide important data on potentially protective immune responses in humans and suggest a careful evaluation of prevaccination sensitivity when investigating vaccine-induced immunity.
authors.affiliation: Tuberculosis Research Unit, Statens Serum Institut, Copenhagen, Denmark.
authors.forename: P
authors.initials: P
authors.lastname: Ravn
authors.forename: H
authors.initials: H
authors.lastname: Boesen
authors.forename: B K
authors.initials: BK
authors.lastname: Pedersen
authors.forename: P
authors.initials: P
authors.lastname: Andersen
mesh_terms: D000293:Adolescent; D000328:Adult; D000942:Antigens, Bacterial / Q000276:immunology; D001500:BCG Vaccine / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis; D003602:Cytotoxicity, Immunologic; D000939:Epitopes / Q000096:biosynthesis; D005260:Female; D006801:Humans; D008213:Lymphocyte Activation; D008297:Male; D009163:Mycobacterium bovis / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*; D018417:Th1 Cells / Q000378:metabolism
chemical_list: D000942:Antigens, Bacterial; D001500:BCG Vaccine; D016207:Cytokines; D000939:Epitopes