The key difference between TNF alpha and beta is that TNF alpha is a less cytotoxic protein of the TNF super family, while TNF beta is a more cytotoxic protein of the TNF super family.
TNF super family is a protein super family of type II transmembrane proteins. These proteins contain a TNF homology domain and forming trimers. Moreover, proteins in this super family can be released from cell membranes by extracellular proteolytic cleavage, and they normally function as cytokines. The proteins of the TNF super family perform a variety of functions, such as regulating immune response and inflammation, proliferation, differentiation, apoptosis, and embryogenesis. This super family contains 19 members and binds to 29 members of the TNF receptor super family. TNF alpha and beta are two proteins that belong to TNF super family.
What is TNF Alpha?
TNF alpha is an adipokine and a cytokine belonging to TNF super family. This protein is a transmembrane protein with a homologous TNF domain. As an adipokine, it promotes insulin resistance and is associated with obesity-induced type 2 diabetes. As a cytokine, it is used for cell signalling by the immune system. Moreover, if macrophages detect a certain infection, they release TNF to alert other immune system cells as part of an inflammatory response.
TNF alpha signalling occurs through two receptors: TNFR1 and TNFR2. TNFR1 is constitutively expressed in most of the cell types, while TNFR2 is restricted to endothelial cells, epithelial cells, and subsets of immune cells. TNF alpha exists as a transmembrane form (mTNF-α) and as a soluble form (sTNF-α). The soluble form is a result of the enzymatic cleavage of transmembrane form through a process called substrate presentation. Furthermore, the main functions of the TNF alpha include regulation of immune cells, induction of fever, cachexia, inflammation, and apoptosis, inhibition of tumorigenesis, viral replication, and response to sepsis.
What is TNF Beta?
TNF beta is a protein that belongs to TNF super family and is more cytotoxic than TNF alpha. It is also known as lymphotoxin alpha. It is a protein found in humans and is encoded by the LTA gene. TNF beta is translated as a 25 kDa glycosylated polypeptide with 171 amino acid residues. TNF beta is also bound to TNFR1 and TNFR2 receptors like TNF alpha. It is transiently expressed on the surface of the activated B and T cells.
The functions of the TNF beta are induction of inflammation and antiviral response, development of secondary lymphoid organs, and playing an important role in tumorigenesis, such as preventing tumor growth and destroying cancerous cell lines. Furthermore, during embryonic development, TNF beta plays an active part in the formation of the gastrointestinal and immune system.
What are the Similarities Between TNF Alpha and Beta?
- TNF alpha and beta are two proteins that belong to TNF super family.
- Both are protein molecules made up of amino acids.
- They are cytokines.
- Both contain TNF homology domains and forming trimers.
- They can bind to TNFR1 and TNFR2 receptors.
- Both proteins show cytotoxicity.
- They play pivotal roles in the immune system of humans.
What is the Difference Between TNF Alpha and Beta?
TNF alpha is a protein that belongs to TNF super family and is less cytotoxic, while TNF beta is a protein that belongs to TNF super family and is more cytotoxic. Thus, this is the key difference between TNF alpha and beta. Furthermore, the molecular weight of TNF alpha is 17.3 kDa, while the molecular weight of TNF beta is 25 kDa.
The below infographic presents the differences between TNF alpha and beta in tabular form for side-by-side comparison.
Summary – TNF Alpha vs Beta
TNF is a super family that contains various proteins playing vital roles in the immune system and defense. TNF alpha and beta are two proteins belonging to TNF super family. They contain TNF homology domain and forming trimers. The key difference between TNF alpha and beta is that TNF alpha is less cytotoxic while TNF beta is more cytotoxic.
1. “Tumor Necrosis Factor Alpha.” An Overview | ScienceDirect Topics.
2. Calmon-Hamaty, Flavia, et al. “Lymphotoxin α Revisited: General Features and Implications in Rheumatoid Arthritis – Arthritis Research & Therapy.” BioMed Central, BioMed Central.
1. “Mouse Tumor Necrosis Factor Alpha” By TK Vallery – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Ijms-21-05932-g004” By Grégorie Lebeau, Damien Vagner, Étienne Frumence, Xavier Guillot, Estelle Nobécourt, Loïc Raffray, and Philippe Gasque: “Deciphering SARS-CoV-2 Virologic and Immunologic Features” (CC BY 4.0) via Commons Wikimedia