TNFβ ELISA Kit, Human

BACKGROUND The human TNF-beta, also known as lymphotoxin-A (LTA), is an important cytokine involved in the development of secondary lymphoid organs and inflammatory responses. This factor is produced predominantly by mitogen-stimulated T-lymphocytes and leukocytes. The factor is secreted also by fibroblasts, astrocytes, myeloma cells, endothelial cells, epithelial cells and a number of transformed cell lines. The synthesis of TNF-beta is stimulated by interferons and IL2. Some pre-B-cell lines and Abelson murine leukemia virus-transformed pre-B-cell lines constitutively produce TNF-beta. The human TNF-beta protein contains 205 amino acids. There are two forms of TNF-beta: cell membrane and extracellular soluble form which is in blood stream and biological fluids. The soluble form of TNF-beta is usually a homotrimer with a relative molecular mass of 60 to 70 kDa, whereas the membrane form of TNF-beta is a heteromeric complex with lymphotoxin beta (TNFc, LTb, TNFSF3). The human TNF-beta shares 35% identity and 50% homology in amino acid sequence with the human TNF-alpha. The biological function of TNF-beta is mediated largely by TNF-alpha receptor 1 and TNF-alpha receptor 2. Several studies suggested that TNF-beta can also recognize LIGHT ( TNFSF14) receptor. The polymorphism of TNF-beta gene in either the coding region or the promoter region has been associated with Crohn disease and myocardial infarction.¹

TNF-beta acts on a plethora of different cells. In general, TNF-beta and TNF-alpha display similar spectra of biological activities in vitro systems, although TNF-beta is often less potent or displays apparent partial agonist activity. TNF-beta is cytolytic or cytostatic for many tumor cells. Hemorrhagic necrosis of tumors induced by TNF-beta in vivo is probably the result of an inhibition of the growth of endothelial cells and the activity of TNF-beta as an anti-angiogenesis factor.² In monocytes TNF-beta induces the terminal differentiation and the synthesis of G-CSF. TNF-beta is a mitogen for B-lymphocytes. In neutrophils TNF-beta induces the production of reactive oxygen species. It is also a chemoattractant for these cells, increases phagocytosis, and also increases adhesion to the endothelium. In addition, TNF-beta induces the synthesis of GM-CSF, G-CSF, IL1, collagenase, and prostaglandin E2 in fibroblasts. TNF-beta promotes the proliferation of fibroblasts and is involved probably in processes of wound healing in vivo. TNF-beta inhibits the growth of osteoclasts and keratinocytes.³

 

REFERENCES  

1. Ruddle, N.H.: Curr. Opin. Immunol. 4: 327-32, 1992
2. Aggarwal, B.B. & Singh, S.:Growth Fact. Cytok. Health Dis. 2: 727-75, 1997
3. Aggarwal, B.B.: Immunol Ser. 56:61-78, 1992 
 

 

ELISA Kits are based on standard sandwich enzyme-linked immunosorbent assay technology. Freshly prepared standards, samples, and solutions are recommended for best results.