The recombinant 65-kD heat shock protein of Mycobacterium bovis Bacillus Calmette-Guerin/M. tuberculosis is a target molecule for CD4+ cytotoxic T lymphocytes that lyse human monocytes.

Abstract

Protective immunity against mycobacteria is dependent on antigen-specific Th lymphocytes. It has been assumed that these Th upon recognition of antigen/MHC secrete macrophage-activating factors that enable effector macrophages to eliminate the intracellular organism (1).Recently, however, we have found that mycobacteria are very potent inducers of antigen-specific CD4+ and CD8+ cytotoxic T (Tc) cells as well as antigen-nonspecific killer cells that lyse human monocytes (2). Also, in experimental animal models, evidence has recently accumulated in favor of an important role for Tc cells in the immune response to mycobacteria (reviewed in reference 3). In addition, Mycobacterium bovis Bacillus Calmette-Guerin (BCG)-reactive human CD4+ T cell clones have been reported to lyse PPD-pulsed target (antigen-presenting) cells (4). The identification ofthe cytotoxic effector cells as well as the antigens that they recognize are of obvious importance for the design of mycobacterial subunit vaccines .Here we report that the recombinant 65-kD heat shock protein (HSP) (5) ofM. bovis BCG, which is identical to the 65-kD protein ofM. tuberculosis, shares >95% sequence homology with the M. leprae 65-kD gene (6) and shows extensive crossreactivity with the latter (reference 7) is an immunodominant antigen for CD4+ BCG-specific Tc cells in a significant number (t 20%) of BCG-responsive individuals. In addition, recombinant 65-kD HSP-stimulated effector cells also efficiently lysed autologous monocytes in the absence of antigen. This observation may shed new light on the role of the 65-kD HSP in autoimmunity.

Lack of cytotoxic activity against Mycobacterium leprae 65-kD heat shock protein (hsp) in multibacillary leprosy patients

“…The development of specific cytotoxicity was directly related to proliferation with all three hsp tested (Fig 2), as has been previously shown by other authors [27,30]. There was no cross-reactivity between the recombinant proteins employed (Table 2), in accordance with the literature [16].…”

“…tuberculosis, and Myco. bovis BCG are potent inducers of antigen-specific HLA-restricted cytotoxic T cells that lyse human macrophages [16,26,30]. In this study we analysed the cytotoxic activity induced by Myco.…”

“…leprae recombinant proteins [11][12][13] and induction of cytotoxic T lymphocytes by the recombinant 65-kD heat shock protein (hsp65) of Myco. bovis BCG have been demonstrated [14][15][16]. These cytotoxic T lymphocytes react with macrophages pulsed with BCG-hsp or Myco.…”

Phenotypic and functional similarities between 5‐azacytidine‐treated t cells and a t cell subset in patients with active systemic lupus erythematosus

“…Autologous Mg killing was measured using a modification of the method described by Ottenhoff et al (24). PBMC (0.2s-O.5 x lo6) were adhered to round-bottomed microtiter wells in 100 pl RPMI/10% AB serum for 1-2 hours, after which the nonadherent cells were removed.…”

“…PBMC (0.2s-O.5 x lo6) were adhered to round-bottomed microtiter wells in 100 pl RPMI/10% AB serum for 1-2 hours, after which the nonadherent cells were removed. Approximately 10% of the cells were assumed to remain adherent (24). The adherent cells were labeled with 2 pCi 51Cr/well (New England Nuclear, Boston, MA) for 3 hours, then washed.…”