A major T cell antigen of Mycobacterium leprae is a 10-kD heat-shock cognate protein

• Published in: The Journal of experimental medicine 1992-01, Vol.175 (1), p.275-284
• Main Authors: Mehra, V, Bloom, B R, Bajardi, A C, Grisso, C L, Sieling, P A, Alland, D, Convit, J, Fan, X D, Hunter, S W, Brennan, P J
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Antigens, Bacterial - analysis; Antigens, Bacterial - genetics; Antigens, Bacterial - immunology; Armadillos; Blotting, Western; Cloning, Molecular; DNA, Bacterial - genetics; DNA, Bacterial - isolation & purification; Gene Library; Genes, Bacterial; Heat-Shock Proteins - analysis; Heat-Shock Proteins - genetics; Heat-Shock Proteins - immunology; Humans; Leprosy - immunology; Molecular Sequence Data; Molecular Weight; Mycobacterium leprae - genetics; Mycobacterium leprae - immunology; Recombinant Proteins - analysis; Recombinant Proteins - immunology; Restriction Mapping; Sequence Homology, Nucleic Acid; T-Lymphocytes - immunology
• ISSN: 0022-1007; 1540-9538
• DOI: 10.1084/jem.175.1.275

Several mycobacterial antigens, identified by monoclonal antibodies and patient sera, have been found to be homologous to stress or heat-shock proteins (hsp) defined in Escherichia coli and yeast. A major antigen recognized by most Mycobacterium leprae-reactive human T cell lines and cell wall-reactive T cell clones is a 10-kD protein that has now been cloned and sequenced. The predicted amino acid sequence of this protein is 44% homologous to the hsp 10 (GroES) of E. coli. The purified native and recombinant 10-kD protein was found to be a stronger stimulator of peripheral blood T cell proliferation than other native and recombinant M. leprae proteins tested. The degree of reactivity paralleled the response to intact M. leprae throughout the spectrum of leprosy. Limiting-dilution analysis of peripheral blood lymphocytes from a patient contact and a tuberculoid patient indicated that approximately one third of M. leprae-reactive T cell precursors responded to the 10-kD antigen. T cell lines derived from lepromin skin tests were strongly responsive to the 10-kD protein. T cell clones reactive to both the purified native and recombinant 10-kD antigens recognized M. leprae-specific epitopes as well as epitopes crossreactive with the cognate antigen of M. tuberculosis. Further, the purified hsp 10 elicited strong delayed-type hypersensitivity reactions in guinea pigs sensitized to M. leprae. The strong T cell responses against the M. leprae 10-kD protein suggest a role for this heat-shock cognate protein in the protective/resistant responses to infection.