Objective To investigate the stimulatory effect of three different heat-treated protein antigens of Mycobacteriumon humanγδT lymphocytes in vitro. Methods Peripheral blood mononuclear cells(PBMCs)isolated from normal subjects were stimulated with three different heat-treated protein antigens from the H37 Ra strain of Mycobacteriumtuberculosis(H37Ra-HAg),the BCG strain of M.tuberculosis(BCG-HAg),and Mycobacteriumsmegmatis(MS-HAg)for12days.The phenotype of expanded lymphocytes was detected with flow cytometry...