Evaluation of immune responses of human T lymphocyte subsets to Mycobacterium tuberculosis lipid antigens / 中国免疫学杂志

ABSTRACT

Objective:Some antigens of M.tb to culture with peripheral blood mononuclear cells ( PBMC) for assaying their proliferation and activation,so as to signify whether lipid antigens of M.tb have specific immune responses in host against M.tb infection or not.Methods:We treated PBMC with several lipid antigens of M.tb to explore the ability of these antigens to activate immunity in healthy individuals.We measured and analyzed cell proliferation by labeling cells with carboxyfluorescein succinimidyl amino ester (CFSE) and subjecting them to flow cytometry (FCM).The production of IFN-γ,TNF-αand IL-4 by T cell subsets (NKT,CD4+, CD8+,andγδT) from healthy donors was analyzed by FCM after stimulation with autologous immature dendritic cells pre-cultured with M.tb lipid antigens.The tested M.tb lipid antigens were the total lipid (TLIP),Acetone-Soluble Lipids (ASLIP),Purified Sulfolipid (PSLIP),Lipoarabinomannan (LAM) and Lipomannan (LM) levels.Medium free of lipid antigens(WCL,CFP,LPS,Mtb-HAg and blank) was used as a control.Results:We found the proportion of proliferative NKT and CD8+T cells significantly increased in all lipid groups (P<0.05).ASLIP,LAM and LM promoted non-proliferative CD4+T cells to secrete IL-4 and proliferative ones to secrete IFN-γ( P<0.05).All lipid antigens promoted both proliferativeγδT cells and CD8+T cells to secrete IFN-γand TNF-α,but the proportion of TNF-α-secreting cells in these populations decreased in the LM group ( P<0.05 ).Conclusion: Lipid antigens may affect the CD1-restricted T cells of the host to fight M.tb infection.