02916nas a2200385   4500000000100000008004100001260001300042653002400055653002400079653001600103653001300119653002400132653001100156653001200167653002600179653002800205653002100233653002500254653003100279653001300310653002500323653003400348653001800382653002800400100001200428700001600440700001300456700001700469700001300486245010600499300001000605490000700615520189400622022001402516       1993                            d  c1993 Dec10aAmino Acid Sequence10aAntigens, Bacterial10aBCG Vaccine10aEpitopes10aHeat-Shock Proteins10aHumans10aleprosy10aLymphocyte Activation10aMolecular Sequence Data10aMolecular Weight10aMycobacterium leprae10aMycobacterium tuberculosis10aPeptides10aRecombinant Proteins10aSequence Homology, Amino Acid10aT-Lymphocytes10aTuberculosis, Pulmonary1 aAdams E1 aBritton W J1 aMorgan A1 aGoodsall A L1 aBasten A00aIdentification of human T cell epitopes in the Mycobacterium leprae heat shock protein 70-kD antigen.  a500-60 v943 a<p>In a number of pathogens, heat shock proteins (hsp) stimulate humoral and cellular immune responses despite significant sequence identity with host hsp. The 70-kD hsp of Mycobacterium leprae, which shares 47% identity with human hsp70 at the protein level, elicited a T cell response in most Myco. bovis (bacille Calmette-Guérin (BCG)) vaccinees as well as leprosy and tuberculosis patients and their contacts. In order to locate T cell epitopes, DNA fragments encoding portions of the 70-kD hsp were expressed in the vector pGEX-2T and tested for T cell reactivity in an in vitro proliferative assay. Cultures of peripheral blood mononuclear cells (PBMC) from BCG vaccinees indicated that the C-terminal half of the molecule contained multiple T cell epitopes, as the T cells from a majority of Myco. leprae hsp70-reactive individuals responded to C-344. Lower proportions of patients with paucibacillary leprosy (36%) and tuberculosis patients (16%) responded to C-344. The smaller C-142 fragment which includes the terminal 70 residues unique to Myco. leprae and is the target for the human antibody response elicited a cellular response in few patients and no vaccinees. In order to map T cell epitopes, two series of synthetic peptides encompassing the region 278-502 were prepared. Using overlapping 12mer and 20mer peptides, this region of the molecule was found to contain several potential T cell epitopes. The longer peptides gave a clearer indication of reactive sequences including regions of the molecule which were not identified with the 12mer peptides. Fine mapping of reactive peptide pools using the 12mer peptides identified two T cell epitopes. Although both were located in regions of the molecule shared with Myco. tuberculosis, one appeared to be cross-reactive with the equivalent human sequence, and thus has the potential to initiate autoimmune responses.</p>  a0009-9104