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C3 is central to the activation of all 3 pathways of complement activation. Initiation of each pathway generates proteolytic enzyme complexes which binds the target surface. These enzymes cleave a peptide bond in C3 releasing the anaphylatoxin C3a and activating C3b. Most of the C3 activated during complement activation never attaches to the surface due to its thioester reaction with water forming fluid phase C3b which is rapidly inactivated by factors H and I forming iC3b. Surface-bound C3b is necessary in all 3 pathways for efficient activation of C5 and formation of C5b-9 complexes that lyse the target cell membrane.

Celiac disease is an enteropathy that is characterized by intestinal lesions of variable severity. Tissue-type transglutaminase (tTG) is believed to be the predominant autoantigen for celiac disease and the corresponding autoantibodies show higher sensitivity and specificity than anti-gliadin antibodies. Highly pure recombinant human tTG is now available to replace the traditionally used tTG fraction from guinea pig.
Tissue-type transglutaminase antigens have been specifically modified for improved handling: exchange of an active site amino acid eliminates the protein cross-linking activity of the enzyme, while maintaining the native three-dimensional structure and the enzyme's secondary GTPase activity. This engineering assures reproducible properties of the antigen preparations through the absence of variable and ill-defined covalent aggregates of tTG antigen and host cell proteins.

CD8B encodes the CD8 beta chain isoforms of the CD8 antigen. CD8 is a cell surface glycoprotein which facilitates efficient cell-cell interactions within the immune system and is located on most cytotoxic T lymphocytes. The T-cell receptor on the T lymphocyte and the co-receptor CD8 antigen identify antigens exposed by an antigen presenting cell (APC) in the context of class I MHC molecules. The functional co-receptor is either a heterodimer composed of one alpha and one beta chain or a homodimer composed of two alpha chains. Both alpha and beta chains share substantial homology to immunoglobulin variable light chains.

CTLA-4 is a member of the immunoglobulin superfamily and encodes a protein which transmits an inhibitory signal to T cells. The protein contains a V domain, a transmembrane domain, and a cytoplasmic tail. Alternate transcriptional splice variants, encoding different isoforms, have been characterized. The membrane-bound isoform functions as a homodimer interconnected by a disulfide bond, while the soluble isoform functions as a monomer. Mutations in this gene have been associated with insulin-dependent diabetes mellitus, Graves disease, Hashimoto thyroiditis, celiac disease, systemic lupus erythematosus, thyroid-associated orbitopathy, and other autoimmune diseases.

ANGPTL3 and ANGPTL4 are angiopoietin-like proteins secreted and expressed mainly by the liver, their role being the regulation of triglyceride metabolism by inhibiting the lipolysis of triglyceride-rich lipoproteins. During different nutritional states (feeding/fasting) the levels of the circulating triglycerides are regulated by Angptl3 and Angptl4 through differential inhibition of Lipoprotein lipase (LPL) as shown by the experimental data. The molecular structure of ANGPTL3 is similar to that of the angiopoietins (vascular endothelial growth factors). Deletion mutants of human Angiopoietin 5 were used in order to demonstrate that the N-terminal domain (fragment 17-207) and not the C-terminal fibrinogen-like domain (fragment 207-460) increased the plasma triglyceride levels in mice.

Chromogranin-A Isoform 1 Preproprotein or CHGA is part of the neuroendocrine secretory proteins of the chromogranin/secretogranin family. CHGA is a precursor of numerus enzymes such as pancreastatin, catestatin, vasostatin-1,vasostatin-2, and parastatin. The protein acts as a negative regulator the neuroendocrine activity of autocrine or nearby cells (paracrine). CHGA causes further production of secretory granules that contains insulin in pancreatic islet beta cells.

CCL13 chemokine is part of the CC chemokine family (TARC). CCL13 protein induces chemotaxis in monocytes, eosinophils, T lymphocytes, and basophils by binding cell surface G-protein linked chemokine receptors such as CCR2, CCR3 and CCR5. CCL13 is induced by the inflammatory cytokines IL1 & TNFA.

SDF-1 (stromal cell-derived factor-1) is small cytokine belonging to the chemokine family that is officially designated Chemokine (C-X-C motif) ligand 12 (CXCL12). It is produced in two forms, SDF-1?/CXCL12a and SDF-1?/CXCL12b, by alternate splicing of the same gene. Chemokines are characterized by the presence of four conserved cysteines, which form two disulfide bonds. The CXCL12 proteins belong to the group of CXC chemokines, whose initial pair of cysteines are separated by one intervening amino acid. CXCL12 is strongly chemotactic for lymphocytes and has been implicated as an important cell co-ordinator during development. During embryogenesis it directs the migration of hematopoietic cells from foetal liver to bone marrow. Mice which were knocked-out for CXCL12 gene were lethal before the birth or within just 1 hour of life. As another role, CXCL12a alters also the electrophysiology of neurons. CXCL12 was shown to be expressend in many tissues in mice (including brain, thymus, heart, lung, liver, kidney, spleen and bone marrow).
The receptor for this chemokine is CXCR4, which was previously called fusin. This CXCL12-CXCR4 interaction used to be considered exclusive (unlike for other chemokines and their receptors), but recently it was suggested that CXCL12 is also bound by CXCR7 receptor.
The gene for CXCL12 is located on human chromosome 10. In human and mouse both CXCL12 and CXCR4 show high identity of sequence: 99% and 90%, respectively.

CCL4L1 (C-C motif chemokine 4-like) is a member of to intercrine beta (chemokine CC) family. The CCL4L1 protein is similar to CCL4 which inhibits HIV replication in peripheral blood monocytes which express CCR5.

Glycogen phosphorylase (PYGL) converts from inactive phosphorylase B to active phosphorylase A by phosphorylation of serine residue 15. Activity of the PYGL enzyme is further regulated by numerous allosteric effectors and hormonal controls. The liver isozyme supplies the glycemic demands of the body in general whereas the brain and muscle isozymes supply just those tissues.

Chemokine (C-C motif) ligand 11 (CCL11) is a small cytokine belonging to the CC chemokine family that is also known as eotaxin. CCL11 selectively recruits eosinophils by inducing their chemotaxis, and therefore, is implicated in allergic responses. The effects of CCL11 are mediated by its binding to a G-protein-linked receptor known as a chemokine receptor. Chemokine receptors for which CCL11 is a ligand include CCR2, CCR3 and CCR5. The gene for human CCL11 (scya11) is encoded on three exons and is located on chromosome 17.

Interleukin-13 is a pleiotropic regulatory cytokine, which shares many of the properties of Interleukin-4. IL-13 is produced primarily by activated T lymphocytes and acts via specific cell surface receptor complexes. Its biological activities include the stimulation of B-cell proliferation and differentiation and the regulation of inflammatory and immune responses.

MHC Class I is a membrane spanning molecule consisting of 2 proteins. MHC Class I is just about 350 amino acids in length, with roughly 75 amino acids at the carboxylic end comprising the transmembrane and cytoplasmic portions. The remaining 270 amino acids, are divided into three globular domains labeled Alpha-1, Alpha-2 and Alpha-3 prime, with Alpha-1 being closest to the amino terminus and Alpha-3 closest to the membrane. The second portion of the molecule is a small globular protein called Beta-2 Microglobulin. It links primarily with the Alpha-3 prime domain and is essential for MHC stability.
The MHC ability to show a vast range of antigenic peptides for T cell recognition needs a compromise between broad specificity and high affinity. Both MHC class I and MHC class II show an exceptional structure while the peptide main chain is tightly bound and peptide side chains show less restrictive interactions. It is primarily the peptide side-chain contacts and conformational variability that ensures that the peptide-MHC complex presents an antigenically unique surface to T cell receptors.

TNFRSF13B (TACI) is a transmembrane receptor protein found predominantly on the surface of B cells (a significant part of the immune system). TACI was at first discovered owing to its ability to interact with calcium-modulator and cyclophilin ligand (CAML). Later on, it was found that TACI plays a key role in humoral immunity by interacting with two members of the TNF family. Also, TACI controls T cell-independent B cell antibody responses, isotype switching, and B cell homeostasis.

The Fas receptor (CD95) mediates apoptotic signaling by Fas-ligand expressed on the surface of other cells. The Fas-FasL interaction plays an important role in the immune system and lack of this system leads to autoimmunity, indicating that Fas-mediated apoptosis removes self-reactive lymphocytes. Fas signaling is also involved in immune surveillance to remove transformed cells and virus infected cells. Binding of FAS to oligimerized FasL on another cell activates apoptotic signaling through a cytoplasmic domain termed the death domain that interacts with signaling adaptors including FAF, FADD and DAX to activate the caspase proteolytic cascade. Caspase-8 and caspase-10 are first activated, to then cleave and activate downstream caspases, and a variety of cellular substrates that lead to cell death. Caspases cleave nuclear lamins, causing the nucleus to break down and lose its normal structure and another caspase substrate is DFF, inducing cleavage and degradation of the genome. Other caspase substrates are involved in cytoskeletal structure, cell cycle regulation and signaling pathways. Activation of JNK kinase, activation of Jun, and production of ceramide may also play roles in Fas-mediated apoptosis. Activation of fas-mediated apoptosis is opposed by I-FLICE and FAP. Viruses and tumors may escape immune surveillance in part through suppression of fas-mediated apoptosis using similar mechanisms.

Carbonic Anhydrase XIII, also known as CA13 is a member of the alpha-carbonic anhydrase family, which catalyzes the rapid interconversion of carbon dioxide and water tobicarbonate and protons, a reversible reaction which occurs relatively slowly in the absence of catalyst. Furthermore, the active siteof nearly all carbonic anhydrases contains a zinc ion; they have been classified as metalloenzymes. At least fivedistinct CA families (?, ?, ?, ? and ?) have been found. These families have no significant a.a sequence resemblance and in just about allcases are considered to be an example of convergent evolution. The ?-CAs have been demonstrated in humans.

UBE2E3 or Ubiquitin-conjugating enzyme E2 E3 is part of the E2 ubiquitinconjugating enzyme family. UBE2E3 is needed for the destruction of mitotic cyclins and for cell cycle progression. The ubiquitination process covalently attaches to a short protein of 76 amino acids called ubiquitin, to a lysine residue on the target protein. When a protein has been tagged with one ubiquitin molecule, other rounds of ubiquitination form a polyubiquitin chain that is recognized by the proteasome's 19S regulatory particle, triggering the ATP-dependent unfolding of the target protein which grants passage into the proteasome's 20S core particle, where proteases degrade the target into short peptide fragments for recycling by the cell.

Human Adiponectin is a secreted protein expressed exclusively in differentiated adipocyte (adipokine). Adiponectin contains a modular structure comprising an N-terminal collagenous domain followed by a C-terminal globular domain. APM-1 plays a role in various physiological processes such as energy homeostasis and obesity. Plasma levels of adiponectin are reduced in obese humans, and decreased levels are associated with insulin resistance and hyperinsulinemia.

C-type Lectin Domain Family 1 Member B, also known as CLEC1B. NK-Natural killer cells express multiple calcium-dependent (C-type) lectin-like receptors, for instance CD94 (KLRD1; MIM 602894) and NKG2D (KLRC4; MIM 602893), which interact with major histocompatibility complex class I molecules and either inhibit or else activate cytotoxicity and cytokine secretion. CLEC1B is a C-type lectin-like receptor which is expressed in myeloid cells as well as in NK cells.

C4BP has a flower shaped structure with each alpha chain radiating out from a central core. The arms are linked by disulfide bonds in the centre and the ends of each arm bind C4b. C4BP acts as a cofactor allowing factor I to split and permanently inactivate C4b. C4b binding protein modulates complement activation of the classical and lectin pathways. C4BP binds to C4b and accelerates the dissociation of C2a from the C3/C5 convertase C4b,C2a. This inactivates the central enzyme of both pathways. Studies have shown that on surfaces densely coated with C4b, C4BP can bind up to four C4b molecules simultaneously.

The HbA1c shows the average amount of glucose in the blood over a period of 3 months. Sugar in the bloodstream can become attached to the hemoglobin in red blood cells (glycosylation). Once the sugar is attached, it stays there for the life of the red blood cell, which is about 120 days. The higher the level of blood sugar, the more sugar attaches to red blood cells. The HbA1c is formed in a non-enzymatic pathway by hemoglobin's standard exposure to elevated plasma levels of glucose. HbA1c is tested to monitor nephropathy and retinopathy in diabetes mellitus.

PKLR is a pyruvate kinase which catalyzes the transphosphorylation of phohsphoenolpyruvate into pyruvate and ATP. That is the rate-limiting step of glycolysis. PKLR gene encodes the L- and R-type isoenzymes through alternate splicing events controlled by different promoters. L-type isoform can also appear as a tetramer and is upregulated by glucose with implications in maturity-onset diabetes of the young.

Lipopolysaccharide is a potent stimulator of monocytes and macrophages, causing secretion of tumor necrosis factor-alpha (TNF-alpha) and other inflammatory mediators. LITAF is a lipopolysaccharide-induced TNF-alpha factor, which is a DNA-binding protein and can mediate the TNF-alpha expression by direct binding to the promoter region of the TNF-alpha gene. The transcription of the LITAF gene is induced by tumor suppressor p53 and has been implicated in the p53-induced apoptotic pathway. Mutations in the LITAF gene cause Charcot-Marie-Tooth disease type 1C (CMT1C) and may be involved in the carcinogenesis of extramammary Paget''s disease (EMPD).