Latency Antigens as Sensors of Different Stages of Tuberculosis

MÓNICA PONTINO; VIRGINIA MEIKLE; JAVIER O JURADO; VIRGINIA PASQUINELLI; MÓNICA LISTE; ÁNGEL CATALDI; VERÓNICA GARCÍA; ALICIA ALITO

Bogotá, Colombia

Congreso; First Inernational Congress Mycobacteria (FICM). Controlling Micobacterias one formidable Challenge for the Twenty First Century.; 2008

Sociedad Latinoamericana de Tuberculosis y otras Micobacteriosis (SLAMTB).

Two thousands millions people may suffer latent Tb infections. Latently infected individuals provide a highly relevant population to study what human protective immune responses against Mycobacterium tuberculosis look like. OBJECTIVE. To test latency antigens and infection markers so as to identify latently infected individuals. METHODOLOGY Whole blood was stimulated with: latency antigens (HspX, Rv2624c, Rv2626c), CFP10, PPD and Pokeweed mitogen as controls. Interferon gamma (IFN-g) was measured in stimulated plasmas belonging to seven cohorts: 1st) Mantoux negative*; 2nd) Mantoux positive; 3rd) TB patients without antibiotic treatment; 4th) TB patients with antibiotic treatment; 5th) ex TB patients; 6th) relapse patients; 7th) patients with other pulmonary diseases. * Four out 8 individuals of cohort 1st are working at TB lab. The others are contacts of TB patient. RESULTS HspX produced high levels of IFN-g (1st 2nd 4th). Middle levels of IFN-g were observed (5th) Low responses were shown (3rd 6th 7th) Rv2624c and Rv2626c produced very low levels of IFN-g in all cohorts. CFP10 showed variable values of stimulation (2nd 3rd 5th 6th) Low levels of IFNg were produced as expected (1st, 7th) CONCLUSIONS HspX produces high levels of IFN-g in healthy individuals (1st 2nd) and in those with antibiotic treatment (4th 5th). First cohort is latently infected but couldn´t be detected by Mantoux. Rv2624c and Rv2626c don´t show a stimulation pattern similar to HspX. CFP10 doesn´t show its condition of infection marker (small size of the sample). Immunodiagnostic can be improved by latency antigens as a contribution to detect latently infected individuals.