02675nas a2200421   4500000000100000008004100001260001300042653002400055653002400079653002300103653002000126653001100146653002100157653001200178653002800190653002500218653003100243653001800274653001700292100001200309700001800321700001400339700001500353700001300368700001300381700001400394700001100408700001300419700001200432700001600444245014900460856006900609300001100678490000700689050001400696520152900710022001402239       2002                            d  c2002 May10aAmino Acid Sequence10aAntigens, Bacterial10aBacterial Proteins10aCross Reactions10aHumans10aInterferon-gamma10aleprosy10aMolecular Sequence Data10aMycobacterium leprae10aMycobacterium tuberculosis10aT-Lymphocytes10aTuberculosis1 aGeluk A1 aMeijgaarden K1 aFranken K1 aSubronto Y1 aWieles B1 aArend SM1 aSampaio E1 aBoer T1 aFaber WR1 aNaafs B1 aOttenhoff T00aIdentification and characterization of the ESAT-6 homologue of Mycobacterium leprae and T-cell cross-reactivity with Mycobacterium tuberculosis.  uhttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC127910/pdf/1187.pdf  a2544-80 v70  aGELUK20023 a<p>In this paper we describe identification and characterization of Mycobacterium leprae ESAT-6 (L-ESAT-6), the homologue of M. tuberculosis ESAT-6 (T-ESAT-6). T-ESAT-6 is expressed by all pathogenic strains belonging to the M. tuberculosis complex but is absent from virtually all other mycobacterial species, and it is a promising antigen for immunodiagnosis of tuberculosis (TB). Therefore, we analyzed whether L-ESAT-6 is a similarly powerful tool for the study of leprosy by examining T-cell responses against L-ESAT-6 in leprosy patients, TB patients, and exposed or nonexposed healthy controls from areas where leprosy and TB are endemic and areas where they are not endemic. L-ESAT-6 was recognized by T cells from leprosy patients, TB patients, individuals who had contact with TB patients, and healthy individuals from an area where TB and leprosy are endemic but not by T cells from individuals who were not exposed to M. tuberculosis and M. leprae. Moreover, leprosy patients who were not responsive to M. leprae failed to respond to L-ESAT-6. A very similar pattern was obtained with T-ESAT-6. These results show that L-ESAT-6 is a potent M. leprae antigen that stimulates T-cell-dependent gamma interferon production in a large proportion of individuals exposed to M. leprae. Moreover, our results suggest that there is significant cross-reactivity between T-ESAT-6 and L-ESAT-6, which has implications for the use of ESAT-6 as tool for diagnosis of leprosy and TB in areas where both diseases are endemic.</p>  a0019-9567