Traditional Chinese medicine can exert an anti-TB effect by regulating the host immune system. Helper T lymphocyte subsets and cytokines secreted by these cells play an important role in the process of anti-TB immunity. The Th1-type immune response is key in the anti-
M. tuberculosis infection response. IFN-γ, IL-2, and TNF are the key immune indexes in the Th1-type immune response. The expression of IFN-γ plays an important role in the anti-TB immune response, and the expression level in the body is closely related to TB[
21-
23]. IFN-γ can promote the proliferation and differentiation of T cells, activate macrophages, and enhance the phagocytic activity and killing effect of T cells and macrophages on
M. tuberculosis. IL-2 is an important factor in regulating the immune response, promoting the production of IFN-γ, and inducing the differentiation of killer cells, such as natural killer cells. TNF can cooperate with IFN-γ to enhance the expression of inducible nitric oxide synthetase and the antibacterial effect of macrophages and promote the formation of tuberculous granuloma[
24,
25]. After infection with
M. tuberculosis, the expression level of IFN-γ generally increases, and after 2 months of intensive anti-TB treatment, the level of IFN-γ decreases in responsive patients[
26]. When the secretion of IL-2 and TNF is insufficient, the immune response cannot completely eliminate
M. tuberculosis but is increased with the improvement in TB after anti-TB treatment[
27]. The cytokines secreted by Th2 cells are mainly IL-4, IL-6, and IL-10, and their main functions are to promote the development of B cells and induce a humoral immune response. IL-4 mainly promotes the differentiation of Th0 cells into Th2 cells and inhibits the expression of cytokines related to Th1 cells[
28]. IL-6 is a B cell stimulator that can induce B cells to undergo differentiation and maturation to produce antibodies and participate in the anti-inflammatory effect of the body, at the same time, IL-6 can cooperate with colony-stimulating factor (CSF) to promote the growth and differentiation of primitive bone marrow-derived cells and enhance the lytic function of natural killer (NK) cells. Liu[
29] showed that the higher the level of IL-6 is
in vivo, the more severe the lung inflammation. IL-10 is an anti-inflammatory cytokine that can reduce the over activation of coactivators in the phagocyte system to weaken antigen presentation[
30]. It has been reported that the long-term control of TB infection requires not only the enhancement of the Th1-type immune response but also the inhibition of the Th2-type immune response[
31]. Lv
et al.[
32] showed that the mice infected with attenuated
M. tuberculosis strain H37Ra mainly produced a Th1-type immune response. IL-17A is an inflammatory factor mainly produced by activated T cells that is induced in the early stage of
M. tuberculosis infection and can promote the activation of T cells, participate in the recruitment of neutrophils and induce various cytokines, such as IL-6, IL-8, and granulocyte-macrophage colony-stimulating factor (GM-CSF)[
33-
35]. In addition, IL-17A participates in the formation of mature granuloma in the lungs during
M. tuberculosis infection, which plays a key role in the prevention of
M. tuberculosis spread[
36]. In TB patients, Th1-type cytokines provide protective immunity, and Th2-type cytokines may promote the inflammatory response and immune damage, while Th17 cytokines play roles in both protection and pathological damage, regulating the T cell response is essential for promoting anti-
M. tuberculosis immunity and preventing widespread immune pathology[
37,
38]. In this study, results for the number of spots representing effector T cells secreting IFN-γ and the levels of cytokines in the culture supernatant of splenic lymphocytes showed that after 3 weeks of treatment, the IFN-γ levels in the TB model and two Chinese medicine treatment groups were significantly increased and the IL-4 level in the TB model group was also significantly increased, while the level of Th2-type cytokines did not increase in the two traditional Chinese medicine treatment groups, which suggested that Th1 and Th2 immune response were both enhanced in the TB model group, while the Th1 immune response was dominant in the two traditional Chinese medicine treatment groups. After 13 weeks of treatment, the IFN-γ level in the TB model group and especially in the JHW group was still significantly increased, but the Th2 cytokine levels were not significantly increased, which indicated that the Th1 immune response was the main response and the Th2 immune response was inhibited in these two groups. The cytokine profile of the NBXH group changed, the IFN-γ level decreased, the IL-2 level significantly increased, and the IL-4 and IL-17A levels increased significantly, which suggested that the Th1 immune response and Th2 immune response tended to be balanced. To date, studies have shown that in TB patients given effective anti-TB treatment, IFN-γ levels decrease while IL-2 levels increase[
26,
27], and these changes in the cytokine profile suggest effective NBXH treatment. In addition, some reports[
39,
40] have shown that the recovery of Th1 and Th2 immune response balance in the treatment of TB is beneficial for the prognosis of patients. NBXH may play a role by regulating the Th1/Th2 immune balance rather than simply enhancing the Th1 response or weakening the Th2 response. After 13 weeks of treatment, the increase in the IL-17A level in some mice was conducive to the formation of granulomas and limited the spread of
M. tuberculosis, which may also be one of the reasons for the reduced pathological damage in the NBXH group.