The tumor microenvironment (TME) is a battleground where immune cells and cancer cells vie against each other. The infiltration capabilities and functional differences of NK cells, T cells, and B cells determine the success or failure of anti-tumor immunity. This article will compare and contrast the mechanisms of infiltration, characteristics of action, and clinical significance of these three types of cells, taking you through the mysteries of this "immune tug-of-war"!

1. NK Cells: The "Rapid Response Force" in the Early Stages of Tumors

2. T Cells: The "Main Force" for Precision Strikes

CD8+ T cells are the "stars" of anti-tumor immunity, activated after dendritic cells (DCs) present tumor antigens, and are chemoattracted to the core area of the tumor through the CXCR3 receptor. A high tumor mutational burden (TMB) can enhance their infiltration and directly kill cancer cells by secreting IFN-γ. In colorectal cancer models, co-infiltration of CD8+ T cells and NK cells can synergistically destroy tumor spheres.

CD4+ T cells exhibit functional differentiation:

Th1 cells activate CD8+ T cells through IFN-γ, enhancing the anti-tumor response;
Treg cells secrete IL-10, TGF-β to suppress immune responses and are often enriched at the tumor edge. It is important to note that T cells are prone to exhaustion, characterized by the upregulation of immune checkpoint molecules such as PD-1, CTLA-4.

3. B Cells: The "Regulator" with Dual Roles

The infiltration and function of B cells are the most controversial, with their roles highly dependent on tumor types and microenvironments:

Anti-tumor potential: In breast cancer and ovarian cancer, B cells co-infiltrate with T cells into tertiary lymphoid structures (TLS), enhancing the immune response by presenting antigens or secreting antibodies. Patients with high CD20+ B cell infiltration in triple-negative breast cancer have better prognoses.
Pro-tumor characteristics: In gastric cancer, tumor-derived B cells significantly inhibit T cell proliferation (Ki-67 expression decreased from 13.9% to 5.1%), possibly involving the upregulation of PD-L1 or the secretion of IL-10, TGF-β. In liver cancer, B cells even mediate immune evasion through IgG.

Comparative Summary: The Triangular Relationship of Synergy and Balance

Prospects: Regulating Infiltration, Optimizing Immunotherapy

Current research suggests that combining targeting of NK cell activation receptors (such as NKG2D), reversing T cell exhaustion (such as PD-1 inhibitors), and modulating B cell functions (such as blocking IL-10) may become key to breaking through tumor immune suppression. Future efforts need to further elucidate the dynamic interactions among the three in different cancer types to provide new ideas for personalized therapy!

May Promotion Event