Differential Early Secreted Antigen Target (ESAT) 6 kDa–induced IFN-γ and SOCS1 expression distinguishes latent and active tuberculosis
Pulmonary and Critical Care
Introduction: Expression of Suppressor of cytokine signaling (SOCS)-1 molecules is increased in patients with tuberculosis (TB). Early Secreted Antigen Target (ESAT)-6 kDa – induced IFN-γ responses indicate Mycobacterium tuberculosis infection. The effect of ESAT6- stimulation on SOCS1 in the host is not known.
Methodology: Healthy asymptomatic controls had a negative (n = 16) or a positive ( n = 13) tuberculin skin test (TST). ESAT6-induced IFN- γ responses classified these controls as positive (EC ESAT6 IFN-γ (+), n = 5) or negative (EC ESAT6 IFN-γ (-), n = 24) responders. Patients had pulmonary (n = 21) or extra-pulmonary (n = 30) tuberculosis. Peripheral blood cells were stimulated with ESAT6 and mRNA expression of IFN- γ and SOCS1 was determined.
Results: ESAT6-induced IFN-γ expression was raised in EC ESAT6 IFN-γ (+) as compared with EC ESAT6 IFN-γ (-), p = 0.019. ESAT6-induced SOCS1 mRNA expression was increased in both pulmonary TB and extra-pulmonary TB patients as compared with both EC groups. ESAT6-induced IFN-γ/SOCS1 mRNA expression ratio was decreased in TB patients as compared with both EC groups.
Conclusion: M. tuberculosis infection induces increased ESAT6-induced IFN- γ responses in both latent and active TB. Our data shows down-regulation of IFN- γ / SOCS1 expression to be induced only in active TB cases, distinguishing them from healthy individuals likely to have latent TB. A decreasing IFN- γ /SOCS1 ratio may leads to reduced Th1 immunity which contributes to inability of the host to control clinical disease.
The Journal of Infection in Developing countries
Masood, K. I.,
Rottenberg, M. E.,
(2014). Differential Early Secreted Antigen Target (ESAT) 6 kDa–induced IFN-γ and SOCS1 expression distinguishes latent and active tuberculosis. The Journal of Infection in Developing countries, 8(1), 59-66.
Available at: http://ecommons.aku.edu/pakistan_fhs_mc_med_pulm_critcare/22