Tumor necrosis factor high

Tumor necrosis factor is a relatively important substance in the human body, and its main function is to resist tumors and cancer. Many people will have high tumor necrosis factor results during examinations, and many people believe that this is caused by tumors. In fact, tumor necrosis factor has many effects, so there are also many reasons for the occurrence of excessive tumor necrosis factor. Below, we will introduce the role of tumor necrosis factor in detail.

1. Direct killing or inhibition

After TNF binds to the corresponding receptor, it moves into the cell and is taken up by the target cell lysosome, resulting in decreased lysosomal stability, leakage of various enzymes, and cell lysis. It is also believed that TNF activates phospholipase A2, releasing superoxide and causing DNA breakage, and phospholipase A2 inhibitors can reduce the anti-disease effect of TNF. TNF can alter the glucose metabolism of target cells, lower the intracellular pH, and lead to cell death.

2. Improve the phagocytic ability of neutrophils

Increase superoxide anion production, enhance ADCC function, stimulate cell degranulation and secretion of myeloperoxidase. Pre-culture of TNF with endothelial cells can increase the expression of MHC class I antigens and ICAM-1, the secretion of IL-1, GM-CSF and IL-8, and promote the adhesion of neutrophils to endothelial cells, thereby stimulating the body's local inflammatory response. The induction effect of TNF-α is stronger than that of TNF-β. TNF stimulates monocytes and macrophages to secrete IL-1 and regulate the expression of MHC class II antigens.

3. Anti-infection

For example, it can inhibit the growth of malarial parasites, inhibit viral replication (such as adenovirus type 2 and herpes virus type 2), inhibit viral protein synthesis, the production and infectivity of viral particles, and kill virus-infected cells. The antiviral mechanism of TNF is not very clear.

4. Improve immunity

TNF is an endogenous pyrogen that causes fever and induces the synthesis of acute phase proteins in hepatocytes. TNF may cause fever by directly stimulating the hypothalamic questioning regulatory center and stimulating macrophages to release IL-1. It can also stimulate other cells to produce IL-6 through IL-1 and TNF-α.

5. Promote cell proliferation and differentiation

TNF promotes the expression of MHC class I antigens on T cells, enhances the proliferation capacity of IL-2-dependent thymocytes and T cells, promotes the production of lymphokines such as IL-2, CSF and IFN-γ, and enhances the proliferation and Ig secretion of B cells stimulated by mitogens or foreign antigens. TNF-α has a growth factor-like effect on certain tumor cells, and synergizes with the proliferation-promoting effects of EGF, PDGF and insulin to promote the expression of EGF receptors. TNF can also promote the expression of oncogenes such as c-myc and c-fos, which are closely related to cell proliferation, causing the cell cycle to shift from the G0 phase to the G1 phase. It has been recently reported that TNF-β (LT) is an autocrine growth factor of EB virus-transformed lymphoblasts, and anti-LT antibodies, sTNFR and TNF-α can inhibit the proliferation of EB virus-transformed lymphoblasts.