T cell exhaustion induced by persistent mycobacterium bovis BCG purified protein derivative stimulation could be restored by a Chinese Herbal Bushen Jianpi Recipe in mice model / 中国免疫学杂志

ABSTRACT

Objective:To evaluate effects of Bushen Jianpi Recipe ( BSJP) on restoring of T cell exhaustion induced by persistent tuberculosis antigens in mice.Methods:The C57BL/6 mice were primed with BCG(5×106 CFU)and boosted with 20μg of Mycobacterium bovis BCG Purified Protein Derivative ( PPD ) once a week and lasted for 16 times to induce T cell exhaustion that happened in late stage of tuberculosis .BSJP was used to treat the mice with immune exhaustion for 3 weeks.Flow Cytometry was used to detect the numbers of CD 4+and CD8+T cells and PD-1 expression.ELISA was used to detect IL-2 and IFN-γsecretion.Bacteria load in lung tissue following BCG challeng was used to detect the protective capability of mice models .Results: Compared with the transient antigen stimulation group,the persistent antigen stimulation group had lower level of IFN-γand IL-2 secretions(P<0.01).The numbers of CD4+and CD8+T cells decreased and the level of inhibitory receptor PD-1 got higher(P<0.01).The protective efficacy against BCG challenging decreased ( P<0.01 ) .After treatment with BSJP , the production of cytokines IFN-γand IL-2 increased ( P<0.01 );the numbers of CD4+and CD8+T cells increased and PD-1 expression level on CD4+T cells decreased(P<0.01);the protective efficacy against BCG challenge increased (P<0.01).The results showed that BSJP can reduce the PD-1 expression,improve the IL-2 and IFN-γsecretion,and increase the protection against BCG challenge .Conclusion:Bushen Jianpi Recipe can restore T cell exhaustion induced by persistent tuberculosis antigen stimulation in mice , which gives a hope to overcome T cell exhaustion in tuberculosis with Chinese herbal in clinic.