Analysis of the components of Mycobacterium tuberculosis heat-resistant antigen (Mtb-HAg) and its regulation of γδ T-cell function.

Background: Mycobacterium tuberculosis heat-resistant antigen (Mtb-HAg) is a peptide antigen released from the mycobacterial cytoplasm into the supernatant of Mycobacterium tuberculosis (Mtb) attenuated H37Ra strain after autoclaving at 121 °C for 20 min. Mtb-HAg can specifically induce γδ T-cell proliferation in vitro. However, the exact composition of Mtb-HAg and the protein antigens that are responsible for its function are currently unknown.

Immune responses induced by Mycobacterium tuberculosis heat-resistant antigen (Mtb-HAg) upon co-administration with Bacillus Calmette-Guérin in mice.

Objectives: To preliminarily assess the immunogenicity of Mtb-HAg in mice and the synergistic effect provided by HAg when co-immunised with BCG.

Methods: Mice were randomly grouped for different immunisations and then spleens were aseptically removed and lymphocytes were extracted for immediate detection of cytokines transcript levels and stimulation index(SI), cytokine secretion and multifunctional antigen-specific T cells were detected after incubation for different times.

Results: HAg extracted from active Mtb is a group of mixed polypeptides with molecular weights of (10-14) kDa.