Human cord blood T-cell receptor alpha beta cell responses to protein antigens of Paracoccidioides brasiliensis yeast forms.
Paracoccidioides brasiliensis causes a chronic granulomatous mycosis, prevalent in South America, and cell-mediated immunity represents the principal mode of protection against this fungal infection. We investigated the response of naive cord blood T cells to P. brasiliensis lysates. Our results show: (1) P. brasiliensis stimulates T-cell expansion, interleukin-2 (IL-2) production and differentiation into cytotoxic T cells; (2) T-cell stimulation depends on P. brasiliensis processing and major histocompatibility complex (MHC) class II expression; (3) the responsive T-cell population expresses alpha beta T-cell receptors (TCR) with different V beta gene products, CD4 and CD45RO; (4) the P. brasiliensis components involved in T-cell expansion primarily reside in a high molecular weight (100,000 MW) and a low molecular weight (< 1000 MW) protein fraction. These results indicate that protein antigens of P. brasiliensis stimulate cord blood CD4 alpha beta T cells, independent from in vivo presensitization, and thus question direct correlation of positive in vitro responses with protective immunity in vivo.
Munk
M E
ME
Department of Immunology, University of Ulm, Germany.
Kaufmann
S H
SH
D000946:Antigens, Fungal / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002478:Cells, Cultured; D005312:Fetal Blood / Q000276:immunology*; D006684:HLA-DR Antigens / Q000276:immunology; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis; D008213:Lymphocyte Activation; D010228:Paracoccidioides / Q000276:immunology*; D010641:Phenotype; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology
D000946:Antigens, Fungal; D006684:HLA-DR Antigens; D007376:Interleukin-2; D016693:Receptors, Antigen, T-Cell, alpha-beta