Induction of antigen-specific CD4+ HLA-DR-restricted cytotoxic T lymphocytes as well as nonspecific nonrestricted killer cells by the recombinant mycobacterial 65-kDa heat-shock protein.
Acquired cell-mediated immunity to intracellular parasites like mycobacteria is dependent on antigen-specific T lymphocytes. We have recently found that mycobacteria not only induce helper T cells but also cytotoxic CD4+ and/or CD8+ T cells as well as nonspecific killer cells that lyse human macrophages in vitro. In addition, we have described that the recombinant heat-shock protein (hsp) 65 of Mycobacterium bovis BCG/M, tuberculosis is an important target antigen for CD4+CD8- cytotoxic T cells. We have now further investigated the cytotoxic effector cells that are induced by the hsp65 of BCG. Purified protein derivative of tuberculin (PPD)- or hsp65-specific cytotoxic T cells specifically lysed PPD, hsp65 of BCG and hsp65 of M. leprae-pulsed macrophages in an HLA-DR-restricted manner. Nonpulsed macrophages were lysed to a much lower but still significant extent. hsp65-induced effector cells expressed CD3, CD5, CD4, CD8 and CD56 markers. Depletion experiments showed that the antigen-specific HLA-DR-restricted killer cell was of the CD5+CD4+CD8-CD56- phenotype. Experiments using N-terminal truncated hsp65 fusion (cro-lacZ) proteins suggested that the N-terminal 65 amino acid residues of the 540 amino acid molecule are critical for the expression of the cytotoxic target epitope(s) in two individuals tested. In addition to inducing antigen-specific cytotoxic effector cells, the hsp65 also triggered nonspecific nonrestricted effector cells with lytic activity against nonpulsed autologous or allogeneic macrophages as well as K-562 and Daudi tumor cells. hsp65-stimulated effector cells produced both interferon and tumor necrosis factor-alpha. An important finding was that hsp65-stimulated effector cells strongly inhibited colony-forming unit formation from live BCG-infected autologous macrophages.
Armauer Hansen Research Institute, Addis Ababa, Ethiopia.
B K
BK
Ab
R
R
Kiessling
J D
JD
Van Embden
J E
JE
Thole
D S
DS
Kumararatne
P
P
Pisa
A
A
Wondimu
T H
TH
Ottenhoff
D000942:Antigens, Bacterial / Q000276:immunology*; D015703:Antigens, CD / Q000032:analysis; D001770:Blood Bactericidal Activity; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D003602:Cytotoxicity, Immunologic; D000939:Epitopes; D006684:HLA-DR Antigens / Q000276:immunology; D006360:Heat-Shock Proteins / Q000276:immunology*; D006801:Humans; D066298:In Vitro Techniques; D007372:Interferons / Q000096:biosynthesis; D007694:Killer Cells, Natural / Q000276:immunology*; D008264:Macrophages / Q000276:immunology; D009161:Mycobacterium / Q000276:immunology*; D011994:Recombinant Proteins; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D014373:Tuberculin / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
D000942:Antigens, Bacterial; D015703:Antigens, CD; D000939:Epitopes; D006684:HLA-DR Antigens; D006360:Heat-Shock Proteins; D011994:Recombinant Proteins; D014373:Tuberculin; D014409:Tumor Necrosis Factor-alpha; D007372:Interferons