PRRDB 2.0 : Pattern Recognition Receptor Database

Advanced Glycation End-products (AGEs) are the result of a chain of chemical reactions after an initial glycation reaction. The intermediate products are known, variously, as Amadori, Schiff base and Maillard products, named after the researchers who first described them. AGEs may be formed external to the body (exogenously) by heating, or cooking, sugars with fats or proteins; or, inside the body (endogenously) through normal metabolism and aging.

Advillin is a member of the gelsolin/villin family of actin regulatory protein. Ca (2+)-regulated actin-binding protein.

Cells that are undergoing programmed cell death.

Beta glucan is a naturally derived polysaccharide which has been studied for its anti-tumor and immune stimulating properties.

Calreticulin is a protein that binds Ca2+ ions (a second messenger molecule in signal transduction), rendering it inactive. Calreticulin binds to misfolded proteins and prevents them from being exported from the Endoplasmic reticulum to the Golgi apparatus. One of calreticulin's immunological functions is its role in the folding and peptide-loading of newly sythesized molecules of the major histocompatability complex (MHC) class I protein.

Dermatan sulfate is a sulfated glycosaminoglycan (GAG) composed of a chain of alternating sugars (N-acetylgalactosamine and glucuronic acid). Chondroitin sulphate B is the alternative name for dermatan sulphate. It is sulphated on the C4 position of GlcNAc but the C5 of the uronic acid has undergone epimerisation to Iduronic acid.

Envelope glycoproteins E1 and E2 are involved in virus attachment to the host cell as well as in virus endocytosis and fusion with host membrane (By similarity). E2 inhibits human EIF2AK2/PKR activation, preventing the establishment of an antiviral state. E2 is a viral ligand for CD209/DC-SIGN and CLEC4M/DC-SIGNR, which are respectively found on dendritic cells (DCs), and on liver sinusoidal endothelial cells and macrophage-like cells of lymph node sinuses.

Flagellin is a protein that forms the flagella, or long tail, in bacterial flagellum. Due to its natural molecular structure, flagellin arranges itself into a hollow cylinder in a helical shape, which is essential to its function. In flagellated bacteria, flagellin is one of the most common proteins in the cell.

Fucoidan is a sulfated polysaccharide found mainly in various species of brown seaweed such as kombu, limu moui, wakame, mozuku, and hijiki.

Gelatin is a protein produced by partial hydrolysis of collagen extracted from the bones and connective tissues of animals.

Glycoinositol-phospholipids (GIPLs) are the major glycolipid class and prominant surface antigens of trypanosomatids parasites. They play important roles in the establishment of chronic parasitic infections. These glycolipids have the general structure, glycan-glucosamine-phosphatidylinositol, and appear to act predominantly as membrane anchors for a diverse family of cell surface proteins.

Glucuronoxylomannan (GXM) is the major capsular polysaccharide of Cryptococcus neoformans. It consisting of a linear backbone of 1,3-linked alpha-D-mannose with mainly xylose and glucuronic acid in side chains.

The endoplasmic reticulum (ER)-resident heat shock protein Gp96 is involved in protein folding and is released into the extracellular space after necrotic cell death. In this context, Gp96 has immunostimulatory properties: it activates dendritic cells or macrophages and delivers associated peptides into the antigen presentation pathway, resulting in the induction of specific T-cell responses.

Glycoprotein from Sendai, para-influenza, Newcastle Disease, and other viruses that participates in binding the virus to cell-surface receptors. The HN protein possesses both hemagglutinin and neuraminidase activity.

Hemagglutinin (HA) or haemagglutinin (BE) is an antigenic glycoprotein found on the surface of the influenza viruses (as well as many other bacteria and viruses). It is responsible for binding the virus to the cell that is being infected. The name "hemagglutinin" comes from the protein's ability to cause red blood cells (erythrocytes) to clump together ("agglutinate") in vitro.

Heat shock protein 60 (HSP60) is a mitochondrial chaperonin that is typically held responsible for the transportation and refolding of proteins from the cytoplasm into the mitochondrial matrix. In addition to its role as a heat shock protein, HSP60 functions as a chaperonin to assist in folding linear amino acid chains into their respective three-dimensional structure. HSP60 possibly plays a role in a "danger signal cascade" immune response. There is also mounting evidence that it plays a role in autoimmune disease.

The 70 kilodalton heat shock proteins (Hsp70s) are a family of ubiquitously expressed proteins. The Hsp70s are an important part of the cell's machinery for protein folding, and help to protect cells from stress.

Laminarin is a polysaccharide carbohydrate very much like starch, except it functions as an energy storage compound for Laminaria and other brown algae like kelp.

Lipoarabinomannan is a glycolipid, and a virulence factor associated with Mycobacterium tuberculosis, the bacteria responsible for tuberculosis. Its primary function is to inactivate macrophages and scavenge oxidative radicals.

Lipopolysaccharide (LPS) is a large molecule consisting of a lipid and a polysaccharide (carbohydrate) joined by a covalent bond. LPS is a major component of the outer membrane of Gram-negative bacteria, contributing greatly to the structural integrity of the bacteria, and protecting the membrane from certain kinds of chemical attack. LPS is an endotoxin, and induces a strong response from normal animal immune systems. It comprises three parts:

• polysaccharide (O) side chains
• core oligosaccharide
• lipid A

Mannan is a plant polysaccharide that is a polymer of the sugar mannose.

Phospholipomannan (PLM) is a phylogenetically unique glycolipid with a phytoceramide moiety expressed at the surface of and shed by C. albicans.

A synthetic polymer of inosine that resembles the RNA of infectious viruses and is used to stimulate the production of interferon by the immune system.

Porins are beta barrel proteins which cross a cellular membrane and act as a pore through which molecules can diffuse. Unlike other membrane transport proteins, porins are large enough to allow passive diffusion - i.e. they act as channels which are specific to different types of molecules. They are present in the outer membrane of Gram-negative bacteria, the mitochondria, and the chloroplast.Porins typically control the diffusion of small metabolites like sugars, ions, and amino acids.

Profilin is an actin-binding protein involved in cytoskeleton dynamics. It is found in most eukaryotic cells and in mammalian cells .

The fusion (F) glycoprotein at the surface of RSV particles is essentiel to their infectivity, as it mediates the fusion of the viral envelope and the cytoplasma membrane of target cell, allowing the viral nucleocapsid to enter the cell cytoplasma. At the surface of infected cells, the F protein induces fusion between the cytoplasma membranes of adjacent cells, giving rise to syncytia.

It is a synthetic molecule belonging to imidazoquinoline family. It is a potent antiviral agent and is speculated to mimic a viral product.

Serum amyloid A (SAA) proteins are a family of apolipoproteins found predominantly associated with high-density lipoprotein (HDL) in plasma, with different isoforms being unequally expressed constitutively and in response to inflammatory stimuli.SAA has been linked to functions related to inflammation, pathogen defense, HDL metabolism, and cholesterol transport and thereby has been implicated in several pathological conditions including atherosclerosis, rheumatoid arthritis, Alzheimer's disease, and cancer. SAA is known best for its role during the acute phase response to an inflammatory stimulus such as infection, tissue injury, and trauma.

The Spike protein (S) is one of the four major structural proteins of the Severe Acute Respiratory Syndrome-Associated coronavirus (SARS-CoV). S proteins are incorporated into the viral envelope. These glycoproteins mediate binding of viral particles to cells, as well as cell-viral membrane fusion.

Surfactant protein (SP)-A belongs to a family of innate host defense proteins termed collectins because of the presence of collagenous and also lectin-like domains. SP-A has a potent immunomodulatory function with the N-terminal and C-terminal portions of the molecule capable of either activating or suppressing functions of cells of the immune system.

Thrombospondins (TSP) are secreted proteins with the ability to inhibit angiogenesis.One of a family of glycoproteins (carbohydrates complexed with proteins) that are made in cells, secreted by cells, and incorporated into cells including blood platelets (thrombocytes) from which they take their name.They are involved in cell adhesion, platelet aggregation (clumping), cell proliferation (growth), angiogenesis (blood vessel formation), tumor metastasis, and tissue repair.

Tissue plasminogen activator (abbreviated PLAT or tPA) is a serine protease normally found on the surface of endothelial cells of veins, capillaries, the pulmonary artery, heart, and uterus, and is secreted after vascular injury. It converts the proenzyme plasminogen to plasmin, a fibrinolytic enzyme.

An insoluble carbohydrate from the cell wall of yeast, used especially in the immunoassay of properdin. Zymosan is an insoluble cell wall polysaccharide of yeast (Saccharomyces cerevisiae). It is mannan-rich.

The 19 kDa antigen (Rv3763), a lipoprotein of M. tuberculosis, elicits high levels of interleukin (IL)-12 from macrophages in addition to its powerful immunomodulatory properties, leading to suppression of antigen-presentation signalling cascades. The Mycobacterium tuberculosis 19-kDa lipoprotein has been reported to stimulate both T and B cell responses as well as induce a number of Th1 cytokines.