L-Selectin belongs to a family of divalent cation dependent carbohydrate-binding glycoproteins or adhesion molecules. L-Selectin is expressed constitutively on lymphocytes, monocytes and granulocytes and interacts specifically with carbohydrate groups on activated endothelial cells. L-Selectin is shed by proteolytic cleavage and circulating levels in biological fluids are used as an indicator of various pathological conditions. Recombinant human L-selectin comprises a 294 amino acid fragment (39-332) corresponding to the mature L-Selectin extracellular domain and is expressed in E.
Intracellular adhesion molecules (ICAM proteins) are ligands for the leukocyte adhesion protein LFA-1 (integrin alpha-L/beta-2). During leukocyte trans-endothelial migration, ICAM-1 engagement promotes the assembly of endothelial apical cups through SGEF and RHOG activation. ICAM-1 acts as a cellular receptor for rhinovirus and also interacts with human herpes virus 8 MIR2 protein. Homozygotes with ICAM1-Kalifi Met-56 seem to have an increased risk for cerebral malaria.
E-Selectin is a cell-surface glycoprotein which plays role in immunoadhesion. E-Selectin mediates the adhesion of blood neutrophils in cytokine-activated endothelium through interactions with PSGL1/SELPLG. It also plays a role in capillary morphogenesis. Recombinant human E-selectin comprises a 379 amino acid fragment (179-557) corresponding to the cysteine rich complement control region and is expressed in E. coli with an amino-terminal hexahistidine tag.
ADAM 10 cleaves the membrane-bound precursor of TNF-alpha at '76-Ala-|-Val-77' to its mature soluble form. ADAM 10 is responsible for the proteolytic release of several other cell-surface proteins, including heparin-binding epidermal growth-like factor, ephrin-A2 and for constitutive and regulated alpha-secretase cleavage of amyloid precursor protein (APP). ADAM 10 contributes to the normal cleavage of the cellular prion protein.
CD40L or CD154 is a membrane glycoprotein and differentiation antigen expressed on the surface of T-cells. The CD40 ligand binds to TNFRSF5 and stimulates B-cell proliferation and secretion of all immunoglobulin isotypes in the presence of cytokines. CD40 ligand has been shown to induce cytokine production and tumoricidal activity in peripheral blood monocytes. It also co-stimulates proliferation of activated T-cells and this is accompanied by the production of IFN-gamma, TNF-alpha, and IL2. The soluble form derives from the membrane form by proteolytic processing.