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The tumor microenvironment (TME) plays an important role in the development of tumors. Immunoregulatory cells and cytokines facilitate cancer cells to avoid immune surveillance. Overexpression of immune checkpoint molecules such as CTLA-4 and PD-1/PD-L1 inhibits immune function and enables cancer cells to avoid clearance by the immune system. Thus, minimizing tumor immunosuppression could be an important strategy for cancer therapy. Currently, many immune checkpoint-targeted drugs, such as PD-1/PD-L1 inhibitors, have been approved for marketing and have shown unique advantages in the clinical treatment of cancers. The concept of "strengthening resistance to eliminate pathogenic factors" in traditional Chinese medicine (TCM) is consistent with the immunotherapy of cancer. According to previous studies, the role of TCM in tumor immunotherapy is mainly associated with the positive regulation of natural killer cells, CD8/CD4 T cells, dendritic cells, M2 macrophages, interleukin-2, tumor necrosis factor- α , and IFN- γ , as well as with the negative regulation of Tregs, myeloid-derived suppressor cells, cancer-associated fibroblasts, PD-1/PD-L1, transforming growth factor- β , and tumor necrosis factor- β. This paper summarizes the current research on the effect of TCM targeting the TME, and further introduces the research progress on studying the effects of TCM on immune checkpoints. Modern pharmacological studies have demonstrated that TCM can directly or indirectly affect the TME by inhibiting the overexpression of immune checkpoint molecules and enhancing the efficacy of tumor immunotherapy. TCM with immunomodulatory stimulation could be the key factor to achieve benefits from immunotherapy for patients with non-inflammatory, or "cold", tumors. [ABSTRACT FROM AUTHOR]

Dietary fish oil has immunomodulatory effects that are partly mediated by its effects on cytokine secretion. In this paper, we examine whether dietary fish oil has different effects on cytokine secretion by T cells and macrophages. Female BalbC mice were fed diets supplemented with 18% fish oil + 2% corn oil or 20% corn oil. Concanavalin A (ConA)- and LPS-induced TNF-alpha and IL-10 secretion by splenocytes was examined using ELISA. Dietary fish oil decreased ConA induced-, but increased LPS-induced, TNF-alpha and IL-10 secretion by total murine splenocytes. Dietary fish oil increased the number of splenocytes secreting TNF-alpha and IL-10, following stimulation with LPS, by 123 and 38%, respectively, but did not affect cytokine secretion by each cell, as determined using enzyme-linked immunospot. Spleens from mice fed the fish oil diet had over 2-fold higher proportion of macrophages with high expression of CD11b than spleens from mice fed the corn oil diet. In addition, fish oil increased the proportion of total and CD11b(+) splenocytes that expressed the LPS receptor complex molecules, CD14 and toll-like receptor (TLR)4/myeloid differentiation factor-2 (MD-2), by 85 and 28%, respectively. The increased proportion of macrophages expressing the LPS receptor complex molecules, CD14 and TLR4/MD-2, in spleens from mice fed the fish oil diet may explain the increased number of cells that secreted the cytokines after LPS stimulation. [ABSTRACT FROM AUTHOR]