Sustained T-cell reactivity to Mycobacterium tuberculosis specific antigens in 'split-anergic' leprosy.
Split anergy represented by delayed-type hypersensitivity skin reaction to tuberculin, but not to leprosin, is known to occur in a distinct proportion of leprosy patients. The mechanism was originally attributed to Mycobacterium leprae-specific suppression of T cells toward common mycobacterial antigens. This study ascertained an alternative explanation, attributing the phenomenon to selective responsiveness to M. tuberculosis-specific epitopes. Indeed, the results of blood T-cell proliferative responses in 11 split-anergic patients showed normal responsiveness to the M. tuberculosis-specific 38 kDa lipoprotein and peptide 71-91 of the 16 kDa antigen but diminished responsiveness to 2 common mycobacterial antigens, represented by the 65 kDa heat shock protein and the fibronectin-binding Ag85 complex, as compared with leprosin responsive patients and healthy contacts. These findings support the hypothesis that split anergy is due to selective recognition of M. tuberculosis-specific epitopes and deletion of T cells reacting to shared mycobacterial antigens.
Kaleab
B
B
MRC Clinical Sciences Centre, Royal Postgraduate Medical School, Hammersmith Hospital, London, UK.
Wondimu
A
A
Likassa
R
R
Woldehawariat
N
N
Ivanyi
J
J
D000293:Adolescent; D000328:Adult; D000942:Antigens, Bacterial / Q000494:pharmacology*; D017635:Clonal Anergy; D000939:Epitopes; D005260:Female; D006801:Humans; D007918:Leprosy / Q000097:blood / Q000276:immunology*; D008213:Lymphocyte Activation / Q000187:drug effects; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D012882:Skin Tests; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology*
D000942:Antigens, Bacterial; D000939:Epitopes