Figure 3.

In the tumor microenvironment (TME), excessive lactic acid promotes the polarization of M1 macrophages to M2 macrophages, thereby suppressing the immune response and facilitating immune escape of tumor cells. Furthermore, lactic acid inhibits the migration and differentiation of monocytes into dendritic cells (DC), thus hindering the antigen presentation process and subsequent T cell activation. Lactic acid can also directly inhibit the function of CD8⁺ T cells and achieve immune suppression by promoting the proliferation of regulatory T cells (Treg).