Immunology

Fas is a member of the tumor necrosis factor (TNF)-receptor superfamily and plays a key role in the physiological regulation of programmed cell death. This receptor contains a death domain which enables the formation of a signaling complex that includes Fas-associated death domain protein (FADD), caspase 8, and caspase 10. The auto-proteolytic processing of these complexed caspases triggers a downstream cascade that leads to membrane-mediated apoptosis.

CD14 is a well-characterized cell-activating receptor for lipopolysaccharide-binding protein (LBP) and peptidoglycan. It is an important modulator for lipopolysaccharide (LPS)-dependent signaling and is a component of the multi-protein complex containing also containing MD2 and toll-like receptor 4 (TLR4). CD14 is an important component of the innate immune response preferentially expressed on mature cells of monocyte lineage. The CD14 protein contains eleven leucine-rich repeats (LRRs).

The enzyme family of DNA polymerases plays a fundamental role in the replication, repair, and recombination of nucleic acid. Its members include DNA Polymerase b (Pol b), DNA Polymerase g (Pol g), and DNA Polymerase m (Pol m). TdT is a very unique and fascinating member of this family because, unlike all other DNA polymerases, TdT synthesizes DNA from only single-stranded DNA.

Viral infection triggers the antiviral cell response by activating the innate cellular immune system that recognizes various viral components. One component of this process is the cytoplasmic helicase RIG-1 which is a pattern recognition receptor.

The NALP family consists of cytoplasmic proteins within the larger CATERPILLER protein family. There exist in short forms (such as NALP4) and long forms (NALP1). NALP proteins include the apoptosis regulator apoptotic protease activating factor 1 (APAF1) and mammalian NOD-LRR proteins, and are thought to play a role in the inflammation and reproduction processes.

The innate immune system is responsible for reacting to viral infections through recognition of various viral components. Like toll-like receptor 3 (TLR3), MDA5 recognizes double-stranded (ds) RNA which is a molecular pattern indicative of viral infection. MDA5 and its relative RIG-1 recognize different types of dsRNA, with MDA5 recognizing poly (I:C). MDA5 is a member of the DEAD/DEAH-box RNA helicase family, which all contain the conserved DEAD motif of Asp-Glu-Ala-Asp.

IL-6 is an immunoregulatory cytokine that functions in inflammation and B-cell maturation. It was originally identified as a B-cell differentiation factor. It is primarily made at sites of acute and chronic inflammation, where it is secreted into serum and induces a transcriptional inflammatory response through the cell surface assembly of interleukin-6 alpha receptor (IL-6R, alpha) and the signaling receptor gp130.

The cluster of differentiation 4 (CD4) protein is a surface, type I membrane-embedded glycoprotein that is found on a wide range of cells: T-lymphocytes, B-cells, macrophages, granulocytes, and developmentally-dependent regions specific to the brain. It interacts with major histocompatibility complex (MHC) class II anti-genes, serves as the human immunodeficiency virus (HIV) receptor, and can initiate/augment early phase T-cell activation.  In immune-mediated and central nervous system (CNS) infectious diseases, CD4 indirectly mediates neuronal damage.

COX2 is an inducible dimeric enzyme belonging to the prostaglandin G/H synthase family that enables cells to respond to growth factors, tumor promoters, and cytokines. Prostaglandins are synthesized through the creation of cyclic endoperoxides from arachidonic acid and COX2 catalyzes the committed step in the biosynthetic pathway.

Also known as OPG, TR1 and OCIF, this gene encodes Osteoprotegerin, a heparin-binding secretory glycoprotein that belongs to the TNF-receptor superfamily. The TNFR superfamily consists primarily of transmembrane proteins that elicit signal transduction in a variety of cells and are known to mediate diverse biological responses, including cytotoxicity and apoptosis, Osteoprotegerin (OPG) was isolated independently by two laboratories in 1997 [1,2].