Abstract: Objective To study interleuk in-1B(IL-1β)and tumor necrosis factor-A(TNF-Zα)secretion of human lymphocytes treated with cell-wall deficient Strep tercoccus pneumoniae.Methods The L-form of S.pneumoniae was induced by penicillin and the pure cultures of the stable L-forms were isolated.The bacterial form and the stable L-form of S.pneumoniae were heat-inactivated and then mixed with the lymphocytes.The mixture were cultured for 24 hours at 37℃ and then the IL-1β and TNF-α in the cultures were detected with ELISA.Results The results showed that IL-1β and TNF-α were detected in the cultures of the bacterial form/lymphocytes and the L-form/lym phocytes.The concentrations of IL-1β and TNF-α in the cultures of L-forms/lymphocytes were lower than that of parental bacte rial/lym phocytes(P<0.05).The dependence of secretion on concentration grade was showed in the culture of L-form(r₁=0.969,r²=0.960).Conclusion The immunogenicity of L-form of S.pneumoniae could stimulate human lymphocyte to secrete IL-1β and TN F-α,but the immunogenictty is lower than that of baterial form.