TY - JOUR
T1 - A Dynamic antigen-specific T-cell responses following point-source exposure to Mycobacterium tuberculosis
AU - Ewer, K
AU - Millington, KA
AU - Deeks, Jonathan
AU - Alvarez, L
AU - Bryant, G
AU - Monk, P
AU - Lalvani, A
PY - 2006/6/29
Y1 - 2006/6/29
N2 - RATIONALE: The kinetics of Mycobacterium tuberculosis-specific Th1-type T-cell responses after M. tuberculosis infection are likely to be important in determining clinical outcome. OBJECTIVE: To investigate the kinetics of T-cell responses, in the context of a point-source school tuberculosis outbreak, in three groups of contacts who differed by preventive treatment status and tuberculin skin test (TST) results: 38 treated TST-positive students, 11 untreated TST-positive staff, and 14 untreated students with negative or borderline TST results. METHODS: We used the ex vivo IFN-gamma enzyme-linked immunospot assay (ELISpot) to track T cells specific for two region of difference 1 (RD1) antigens, early secretory antigenic target 6 and culture filtrate protein 10, for 18 mo after cessation of tuberculosis exposure. MAIN RESULTS: The treated TST-positive students had an average 68% decline in frequencies of RD1-specific IFN-gamma-secreting T cells per year (p <0.0001) and 6 of 38 students had no detectable RD1-specific T cells by 18 mo. No change in frequencies of these cells was observed in the untreated TST-positive staff (p = 0.38) and none were ELISpot-negative at 18 mo. Of the 14 untreated students, 7 were persistently ELISpot-positive (all of whom had borderline TST results), and 7 became ELISpot-negative (all but one had negative TST results) during follow-up. CONCLUSIONS: The decrease in M. tuberculosis-specific T cells and their disappearance in a proportion of treated students likely reflect declining antigenic and bacterial load in vivo induced by antibiotic treatment. The observed disappearance of M. tuberculosis-specific T cells in the untreated TST-negative contacts suggests that an acute resolving infection may occur in some contacts.
AB - RATIONALE: The kinetics of Mycobacterium tuberculosis-specific Th1-type T-cell responses after M. tuberculosis infection are likely to be important in determining clinical outcome. OBJECTIVE: To investigate the kinetics of T-cell responses, in the context of a point-source school tuberculosis outbreak, in three groups of contacts who differed by preventive treatment status and tuberculin skin test (TST) results: 38 treated TST-positive students, 11 untreated TST-positive staff, and 14 untreated students with negative or borderline TST results. METHODS: We used the ex vivo IFN-gamma enzyme-linked immunospot assay (ELISpot) to track T cells specific for two region of difference 1 (RD1) antigens, early secretory antigenic target 6 and culture filtrate protein 10, for 18 mo after cessation of tuberculosis exposure. MAIN RESULTS: The treated TST-positive students had an average 68% decline in frequencies of RD1-specific IFN-gamma-secreting T cells per year (p <0.0001) and 6 of 38 students had no detectable RD1-specific T cells by 18 mo. No change in frequencies of these cells was observed in the untreated TST-positive staff (p = 0.38) and none were ELISpot-negative at 18 mo. Of the 14 untreated students, 7 were persistently ELISpot-positive (all of whom had borderline TST results), and 7 became ELISpot-negative (all but one had negative TST results) during follow-up. CONCLUSIONS: The decrease in M. tuberculosis-specific T cells and their disappearance in a proportion of treated students likely reflect declining antigenic and bacterial load in vivo induced by antibiotic treatment. The observed disappearance of M. tuberculosis-specific T cells in the untreated TST-negative contacts suggests that an acute resolving infection may occur in some contacts.
U2 - 10.1164/rccm.200511-1783OC
DO - 10.1164/rccm.200511-1783OC
M3 - Article
C2 - 16799072
SN - 1535-4970
VL - 174
SP - 831
EP - 839
JO - American Journal of Respiratory and Critical Care Medicine
JF - American Journal of Respiratory and Critical Care Medicine
IS - 7
ER -