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Fas and Fas Ligand (FasL) are members of the TNF superfamily and are type I and type II transmembrane proteins, respectively. Binding of FasL to Fas initiates apoptosis in Fas-bearing cells. The apoptosis mechanism involves the recruitment of pro-caspase 8 through an adaptor molecule named FADD followed by processing of the pro-enzyme to active forms. These active caspases subsequently cleave a variety of cellular substrates leading to the eventual cell death. sFasR is able to inhibit FasL-induced apoptosis by acting as a decoy receptor whicht serves as a sink for FasL. The full length Fas Receptor is a 319 a.a type I transmembrane protein, which contains a 157 a.a extracellular domain, a 17 a.a transmembrane domain, and 145 a.a cytoplasmic domain. The mature human Fas ECD shares 55%, 58%, a.a sequence identity with the mouse, rat, Fas, respectively.

CD93, is a receptor or else an element of a larger receptor complex for C1q, MBL2-mannose-binding lectin and SPA-pulmonary surfactant protein A. CD93 mediates the enhancement of phagocytosis in monocytes as well as macrophages upon interaction with soluble defense collagens. CD93 takes part in the intercellular adhesion. Furthermore, CD93 was expressed on (pre) plasmablasts/plasma cells, including long-lived plasma cells which demonstrated decreased cell cycle activity, high levels of isotype-switched Ig secretion, as well as modification of the transcriptional network. CD93 is vital for the maintenance of plasma cells in bone marrow niches.

T-cell surface glycoprotein CD3 zeta chain (CD247) is a member of the CD3Z/FCER1G family. CD247 is T-cell receptor zeta, which along with T-cell receptor alpha/beta and gamma/delta heterodimers, and also with CD3-gamma, -delta and -epsilon, creates the T-cell receptor-CD3 complex. The zeta chain has a central role in coupling antigen recognition to several intracellular signal-transduction pathways. Low expression of the CD247 antigen causes impaired immune response.

BCL2-Like 1 (BCL2L1) belongs to the BCL-2 protein family. BCL2L1 is found at the outer mitochondrial membrane controls outer mitochondrial membrane channel (VDAC) opening. In addition, BCL2L1 regulate s a switch between cell death modes during mitotic arrest.

TNFRSF4, also known as TNF Receptor Superfamily Member 4, is a T cell co-stimulatory molecule which belongs to the TNF receptor superfamily. TNFRSF4 coordinates with other co-stimulatory substances such as CD28, CD40, CD30, CD27 and 4-1BB to control the activation of the immune response. TNFRSF4 takes a vital part in antigen-specific T cell expansion as well as survival. TNFRSF4 is up-regulated on CD4+ and CD8+ T cells upon engagement of the TCR by antigen presenting cells along with co-stimulation by CD40-CD40 Ligand and CD28-B7. In addition, TNFRSF4 regulates cytokine production from T cells, antigen presenting cells, natural killer cells and natural killer cells. TNFRSF4 regulates cytokine receptor signaling.

Hepatitis A Virus Cellular Receptor 2 (HAVCR2) is a member of the immunoglobulin superfamily. HACVR2 controls macrophage activation. HACVR2 inhibits T-helper type 1 lymphocyte (Th1)-mediated auto- and alloimmune responses and stimulates immunological tolerance.

TREM2 is a membrane protein that forms a receptor signaling complex with TYROBP. TREM2 may be involved in chronic inflammation by triggering the production of constitutive inflammatory cytokines. Defects in the TREM2 gene are a source of polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy (PLOSL).

CD166 antigen isoform 2 (ALCAM) is a type 1 membrane glycoprotein and belongs to the immunoglobulin superfamily. ALCAM is expressed on thymic epithelium, microvascular endothelium, activated lymphocytes and monocytes, and monocyte-derived dendritic cells. CD166 and CD6 interaction plays a role in T cell development and T cell regulation, as well as in the binding of T cells and B cells to activated leukocytes.

XCL1 is a small cytokine belonging to the XC chemokine family that is also known as lymphotactin. It is located in high levels in spleen, thymus, intestine and peripheral blood leukocytes, and at lower levels in lung, prostate gland and ovary. Cellular sources for XCL1 include activated thymic and peripheral blood CD8+ T cells. This chemokine attracts T cells. In humans, XCL1 is closely related to another chemokine called XCL2, whose gene is found at the same locus on chromosome 1. XCL1 induces it chemotactic function by binding to a chemokine receptor called XCR1.

B cell-activating factor (BAFF) enhances B-cell survival in vitro and is a regulator of the peripheral B-cell population. Overexpression of Baff in mice results in mature B-cell hyperplasia and symptoms of systemic lupus erythematosus (SLE). Also, some SLE patients have increased levels of BAFF in serum. Therefore, it has been proposed that abnormally high levels of BAFF may contribute to the pathogenesis of autoimmune diseases by enhancing the survival of autoreactive B cells. The protein encoded by this gene is a receptor for BAFF and is a type III transmembrane protein containing a single extracellular cysteine-rich domain. It is thought that this receptor is the principal receptor required for BAFF-mediated mature B-cell survival.

LYVE-1 has been identified as a major receptor for HA (extracellular matrix glycosaminoglycan hyaluronan) on the lymph vessel wall. The deduced amino acid sequence of LYVE-1 predicts a 322-residue type I integral membrane polypeptide 41% similar to the CD44 HA receptor with a 212-residue extracellular domain containing a single Link module the prototypic HA binding domain of the Link protein superfamily. Like CD44, the LYVE-1 molecule binds both soluble and immobilized HA. However, unlike CD44, the LYVE-1 molecule colocalizes with HA on the luminal face of the lymph vessel wall and is completely absent from blood vessels. Hence, LYVE-1 is the first lymph-specific HA receptor to be characterized and is a uniquely powerful marker for lymph vessels themselves.

Galectin-4 is a member of the subfamily of galectins composed of two carbohydrate recognition domains having similar peptide chains. The galectins are a family of beta-galactoside-binding proteins having a role in modulating cell-cell and cell-matrix interactions, which inhibits chronic inflammations, GVHD, and allergic responses. LGALS4 expression is limited to small intestine, colon, and rectum, and it is underexpressed in colorectal cancer. LGALS4 binds as an endogenous ligand to glycosphingolipids having 3-O-sulfated Gal residues and bind as well to cholesterol-3-sulfate. LGALS4 takes part in cell adhesion. LGALS4 plays a role in crosslinking the lateral cell membranes of the surface-lining epithelial cells, thus supporting epithelial integrity against mechanical stress exerted by the bowel lume. LGALS4 is in charge of intestinal inflammation via selective regulation of peripheral and mucosal T-cell cell cycle, in addition to cell death by apoptosis of T-cells by a pathway independent of the activation of caspases. LGALS4 blockade decreases TNF-alpha inhibitor induced T-cell death. LGALS4 decreases pro-inflammatory cytokine secretion including IL-6 & IL-17.

The protein encoded by this gene is a member of the TNF-receptor superfamily. This receptor contributes to the clonal expansion, survival, and development of T cells. It can also induce proliferation in peripheral monocytes, enhance T cell apoptosis induced by TCR/CD3 triggered activation, and regulate CD28 co-stimulation to promote Th1 cell responses. The expression of this receptor is induced by lymphocyte activation. TRAF adaptor proteins have been shown to bind to this receptor and transduce the signals leading to activation of NF-kappaB.

The IL-6 receptor complex is composed of two membrane glycoproteins: the low affinity receptor and the signaltransducing component. The soluble form of IL6R is found in the urine of healthy adult humans and the serum of HIV positive individuals, as well as in the cell culture supernatants of stimulated PBMC’s. This soluble form of IL6R results from either proteolytic cleavage from the membrane, or an isoform derived splice variant.

RELTis expressed in hematopoietic tissues and peripheral blood leukocytesand is a part of thetumor necrosis factor receptor superfamily. RELT mediates activation of NF-kappa-B and takes part in T-cell activation.overexpression of RELT in HEK-293 cells induces p38 and JNK signalling and leads to apoptosis. it can also costimulate T-cell proliferation in the presence of CD3 signalling.

The Defensin family are highly similar in their protein sequence and are microbicidal & cytotoxic peptides made by neutrophils. Beta Defensin-1 is an antimicrobial peptide having the resistance of epithelial surfaces to microbial colonization. Beta Defensin-1 has close proximity to Defensin Alpha-1 and has been implicated in the pathogenesis of cystic fibrosis.
Skin of patients having atopic dermatitis patients and mycosis fungoides (non-lesional and lesional) show lower human Beta Defensin-1 mRNA expression and higher human Beta Defensin-2 and human Beta Defensin-3 mRNA expression.
Beta Defensin is highly expressed by epithelial cells.
Beta-defensin 1 may play a role in the pathogenesis of severe sepsis.

Crk-like protein (CRKL) is a protein kinase containing SH2 and SH3 (src homology) domains which activates the RAS and JUN kinase signaling pathways and transforms fibroblasts in a RAS-dependent manner. CRKL is a substitute of the BCR-ABL tyrosine kinase, it also has a role in fibroblast transformation by BCR-ABL, and has oncogenic potential.

L-Selectin belongs to a family of divalent cation-dependent carbohydrate-binding glycoproteins or adhesion molecules. The L-Selectin molecule is composed of various domains: one homologous to lectins, one to epidermal growth factor, and two to the consensus repeat units found in C3/C4 binding proteins.
L-selectin is expressed constitutively on lymphocytes, monocytes and granulocytes and interacts specifically with carbohydrate groups on activated endothelial cells. L-Selectin may be shed by proteolytic cleavage and circulating levels in biological fluids may be used as an indicator of various pathological conditions. L-Selectin is cleaved by ADAM17.
L-selectin works as a "homing receptor" for leukocytes to enter secondary lymphoid tissues via the high endothelial venules. Ligands present on endothelial cells will attach to leukocytes expressing L-selectin, which causes the leukocytes to become localized at that juncture. The receptor is also located on the cell surfaces of "naive" T cells, which have not yet encountered their particular antigen. This surface expression is lost following the cells activation.

CD23 is a 45kDa glycoprotein, which is present on a subpopulation of freshly isolated peripheral blood and tonsil B cells and strongly expressed on EBV-transformed B lymphoblasts. The CD23 molecule is identical to the low affinity IgE receptor found on B cells. Expression of CD23 has been detected in neoplastic cells from cases of B cell chronic lymphocyctic leukaemia and some cases of centroblastic/centrocytic lymphoma.

CD69 is a type 2 transmembrane glycoprotein which belongs to the C-type lectin family. CD69 is a very early activation Ag of T lymphocytes. The expression of CD69 is induced upon activation of T lymphocytes, and CD69 takes part in proliferation. Moreover, CD69 acts to transmit signals in natural killer cells as well as platelets. CD69 functions in the pathogenesis of allergen induced eosinophilic airway inflammation and responsiveness. Among the diseases which are associated with CD69: cd3gamma deficiency and mast cell disease.

Chloride channels are various group of proteins that control fundamental cellular processes including stabilization of cell membrane potential, transepithelial transport, regulation of intracellular pH, and maintenance of cell volume. CLIC1 is part of the p64 family and is localized to the cell nucleus. CLIC1 displays both nuclear and plasma membrane chloride ion channel activity. CLIC1 inserts into membranes and forms chloride ion channels. CLIC1 channel activity depends on the pH. CLIC1 membrane insertion is redox-regulated and happens under oxydizing conditions.

Integrins are heterodimeric integral membrane proteins composed of an alpha chain and a beta chain. This I-domain containing alpha integrin combines with the beta 2 chain (ITGB2) to form a leukocyte-specific integrin referred to as macrophage receptor 1 ('Mac-1'), or inactivated-C3b (iC3b) receptor 3 ('CR3'). The alpha M beta 2 integrin is important in the adherence of neutrophils and monocytes to stimulated endothelium, and also in the phagocytosis of complement coated particles. Integrin alpha-m/beta-2 is implicated in various adhesive interactions of monocytes, macrophages and granulocytes as well as in mediating the uptake of complement-coated particles. CD-11b is identical with cr-3, the receptor for the ic3b fragment of the third complement component. CD-11b probably recognizes the r-g-d peptide in c3b. Integrin alpha-m/beta-2 is also a receptor for fibrinogen, factor x and icam1. it recognizes p1 and p2 peptides of fibrinogen gamma chain.

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.