Mycobacterium Tuberculosis Whole Cell Lysate And Total Lipids’ Effect On Activation And Proliferation Of Human Peirpheral Blood Mononuclear Cells

Background and Objective Tuberculosis (TB) caused by mycobacterium tuberculosis(Mtb) is one of the oldest infectious diseases known to human, but so far, the preventionand treatment to it is still unsatisfactory. In recent years, tuberculosis is still one of themost important cause of death by a single pathogen infection worldwide, and thenumber of cases continue to increase. The BCG vaccine, as the only effective protectivevaccine, has protected human for nearly one hundred years. The world healthorganization (WHO) study confirmed that the effect of BCG vaccine againsttuberculosis, for children, especially serious types of tuberculosis, such as tuberculousmeningitis, acute miliary tuberculosis and so on is quite obvious, but its efficacy inpreventing pulmonary TB in adults is variable. So it is imperative to develop newvaccine. At present, most of Mtb vaccine and T cell epitope research focuses on solubleprotein secreting to the outside of the cell that is presented by class Ⅱ (MHC)molecule. The antigen of cell wall composition is poorly understood. Mtb lipids in thecell wall, like a thick layer of protective capsule, can withstand adverse environment.The immunomodulatory effects of lipid composition, plays a role in the host innateimmune and adaptive immune response induction, prompting that lipid metabolism maybe the core of Mtb unusual ability of escape. This experiment is to observe the effect ofMtb Whole Cell Lysate (WCL) antigen and Total Lipids (TLIP) antigen in peripheralblood mononuclear cells (PBMC) activation and proliferation, and primarily discuss onwhether the lipid antigen plays a specific role in tuberculosis infection. Methods: PBMC from healthy adults were stimulated by WCL or TLIP, and cultured inthe presence of recombinant human interleukin2(IL-2)(50u/ml) to maintain cellproliferation. The group in which only IL-2added was as control. After having culturedfor6to12days, cells were collected. Cells proliferation and cytokine (IFN-γ) wereanalyzed by flow cytometry.Results: The data showed that both WCL group and TLIP group could activate T cells,especially on the9thday. Compared with the control group, the percentage of CD8+Tcell was decreased significantly while that of CD4-CD8-T cell was increasedsignificantly in WCL group; the proportions of CD4+T cell and CD4+CD8+T cell wereelevated significantly in TLIP group (P<0.05). In the early days, the WCL group canstimulate γδT cells effectively, with the reduction of γδT cells in TLIP group comparedwith control group (P<0.05). On the12th days, the analytical results of theT-Lymphocyte subsets producing IFN-γ showed：the percentage of CD8+T cell of WCLgroup and TILP group was both significantly higher than that of the control group(P<0.05); the percentage of CD8-T cell of WCL group was lower than that of thecontrol group (P<0.05) while it was greater in the TILP group compared with thecontrol group (P<0.05).Conclusion These data support that Mtb TLIP plays a role as WCL to activate specificimmune response to Mtb. TLIP is a possible novel vaccine component.