Bonemarrow Stromal Ag 1/CD157

Bone marrow stromal cell antigen-1 is ADP-ribosyl cyclases 2 enzyme and is also known as CD157. BST1 is a stromal cell line-derived glycosylphosphatidylinositol-anchored molecule that facilitates pre-B-cell growth (1). BST1/CD157 molecule displays two distinct domains in its extracellular component. The first is implicated in the enzymic activities of the molecule and the second features adhesion/signalling properties.  After stress or inflammation BST1 is releases in extracellular compartment.  It is one of the key factors in regulation of innate immunity. BST1 is a pleiotropic ectoenzyme which belongs to the CD38 family. Bst1 has 33% amino acid sequence similarity with CD38. These molecules are involved in the metabolism of NAD(+), capable of consuming extracellular NAD(+). The BST1/CD157 gene is located synthenicaly on chromosome 4p15 alongwith CD38.

BST1 is expressed in stromal cells, human neutrophils, leukocytes  and corneal cells. In eye it has different from CD38 profile of expression and is  expressed by basal limbal clusters, a p63(+)/cytokeratin 19(+) cell subset reported to contain corneal stem cells, and by stromal cells. BST1 expression is increased in rheumatoid arthritis cell line (2). This BST1 overexpession in stromal cells may lead to polyclonal B-cell abnormalities in rheumatoid arthritis patients. BST1 is expressed as a 42- to 45-kDa doublet.  It is physically interacts with CD11b/CD18 complex in human neutrophils. Its function is described as NAD+ nucleosidase activity and hydrolase activity. It involved in process of humoral immune response, metabolic process and multicellular organismal development (6).  Crystal structures of the extracellular region of human BST-1 at atomic resolution in the free form and in complexes with five substrate analogues: nicotinamide, NMN, ATPgamma-S, ethenoNADP, and ethenoNAD has been deduced (5). The BST1 expression is decreased  and was deficient in paroxysmal nocturnal hemoglobinemia; crucial to regulation of innate immunity during inflammation.

BST1-selective antibodies were generated against unique antigenic peptide sequences form BST1 protein, this peptide sequence was not found in any other protein listed in the gene bank.  The BST1 antibodies were affinity purified over immobilized antigen based chromatography, and the purified immunoglobulins are stabilized in antibody stabilization buffer.  FabGennix Int. Inc., will also provide limited quantities of antigenic blocking peptide for BST1.  Antibodies to several other Innate Immunity targets are also available from FabGennix International Inc.  For a complete list of antibodies please visit http://www.fabgennix.com.  FabGennix Inc. will conjugate antibodies with secondary enzymes (alk-Pase or HRP) or fluorescent probes upon request at a nominal cost.  FabGennix Int. Inc., will also provide western blot positive controls for it antibodies in ready-to-use buffer.   Limited quantities of antigenic blocking peptide is available (Please inquire before placing orders).

For research use only, not for diagnostic or therapeutic use.