02865nas a2200457 4500000000100000008004100001260001300042653002400055653002300079653001100102653003100113653003100144653001100175653001100186653002100197653000900218653003100227653002500258653001500283653002600298653002800324100001400352700001200366700001600378700001200394700001400406700001600420700001500436700001600451700001200467700001400479700001600493700001400509245011500523856006900638300001200707490000700719050001600726520165100742022001402393 2002 d c2002 Dec10aAntigens, Bacterial10aBacterial Proteins10aBrazil10aCD4-Positive T-Lymphocytes10aCD8-Positive T-Lymphocytes10aFemale10aHumans10aInterferon-gamma10aMale10aMycobacterium tuberculosis10aRecombinant Proteins10aTuberculin10aTuberculosis, Pleural10aTuberculosis, Pulmonary1 aCardoso F1 aAntas P1 aMilagres AS1 aGeluk A1 aFranken K1 aOliveira EB1 aTeixeira H1 aNogueira SA1 aSarno E1 aKlatser P1 aOttenhoff T1 aSampaio E00aT-cell responses to the Mycobacterium tuberculosis-specific antigen ESAT-6 in Brazilian tuberculosis patients. uhttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC132944/pdf/0142.pdf a6707-140 v70 aCARDOSO20023 a
The Mycobacterium tuberculosis-specific ESAT-6 antigen induces highly potent T-cell responses and production of gamma interferon (IFN-gamma), which play a critical role in protective cell-mediated immunity against tuberculosis (TB). In the present study, IFN-gamma secretion by peripheral blood mononuclear cells (PBMCs) in response to M. tuberculosis ESAT-6 in Brazilian TB patients was investigated in relation to clinical disease types, such as pleurisy and cavitary pulmonary TB. Leprosy patients, patients with pulmonary diseases other than TB, and healthy donors were assayed as control groups. Sixty percent of the TB patients indeed recognized M. tuberculosis ESAT-6, as did 50% of the leprosy patients and 60% of the non-TB controls. Nevertheless, the levels of IFN-gamma in response to the antigen ESAT, but not to antigen 85B (Ag85B) and purified protein derivative (PPD), were significantly lower in controls than in patients with treated TB or pleural or cavitary TB. Moreover, according to Mycobacterium bovis BCG vaccination status, only 59% of the vaccinated TB patients responded to ESAT in vitro, whereas 100% of them responded to PPD. Both CD4 and CD8 T cells were able to release IFN-gamma in response to ESAT. The present data demonstrate the specificity of ESAT-6 of M. tuberculosis and its ability to discriminate TB patients from controls, including leprosy patients. However, to obtain specificity, it is necessary to include quantitative IFN-gamma production in response to the antigen as well, and this might limit the use of ESAT-6-based immunodiagnosis of M. tuberculosis infection in an area of TB endemicity.
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