The proliferation response of γδT cells to the antigen from heat-treated Mycobacterium tuberculosis H37Ra (M.tb Ag) was used as a good model in γδT cell research. From preliminary research it is found that activated NK cells positively elevated γδT cells proliferation after simulating PBMCs with M. tb Ag. To investigate different behaviors of NK cells, γδNKT cells, γδT cells and relationships between these cell subsets, activation and proliferation of different cell subsets of PBMCs in response to M. tb Ag were analyzed. We demonstrated that NK cells, γδNKT cells and γδT cells could be activated after stimulation with M. tb Ag. γδNKT cells and γδT cells proliferated while the number of NK cells decreased after 11 day-simulation with M. tb Ag. Meanwhile, at the early time of stimulation the cytotoxicity of PBMCs was enhanced. Cellular & Molecular Immunology.2004;1(6):467-470.