Recombinant Human BAFF

B-cell activating factor (BAFF) is the tumor necrosis factor ligand superfamily member 13B (TNFLSF13B), also known as B Lymphocyte Stimulator (BLyS) and TNF- and APOL-related leukocyte expressed ligand (TALL-1) and the Dendritic cell-derived TNF-like molecule (CD257 antigen; cluster of differentiation 257).

BAFF is a glycoprotein which undergoes glycosylation at residue 124. It is expressed as transmembrane protein on various cell types including monocytes, dendritic cells and bone marrow stromal cells. The transmembrane form can be cleaved from the membrane, generating a soluble protein fragment. BAFF is the natural ligand of three unusual tumor necrosis factor receptors named BAFF-R, TACI, and BCMA, all of which have differing binding affinities for it. These receptors are expressed mainly on mature B lymphocytes (TACI is also found on a subset of T-cells and BCMA on plasma cells). TACI binds worst since its affinity is higher for a protein similar to BAFF, called A Proliferation Inducing Ligand (APRIL). BCMA displays an intermediate binding phenotype and will work with either BAFF or APRIL to varying degrees. Signaling trough BAFF-R and BCMA stimulates B lymphocytes to undergo proliferation and to counter apoptosis. All these ligands act as heterotrimers (i.e. three of the same molecule) interacting with heterotrimeric receptors.

BAFF provides critical survival signals to a subset of B cells with intermediate maturation status (T2 B cells) during the immune response. BAFF also plays an important role in the development of lymphoid tissue and enhances the survival of activated memory B cells. Human and mouse BAFF share 86% aa sequence identity.

The biological activity of Human BAFF was assayed using human lyphoblast RPMI 8226 cells and showed a neutralization ED₅₀ of 2 ng/ml.

MAVQGPEETV TQDCLQLIAD SETPTIQKGS YTFVPWLLSF KRGSALEEKE NKILVKETGY FFIYGQVLYT DKTYAMGHLI QRKKVHVFGD ELSLVTLFRC IQNMPETLPN NSCYSAGIAK LEEGDELQLA IPRENAQISL DGDVTFFGAL KLL

Lyophilized

The predicted molecular weight of Recombinant Human BAFF is Mr 17.0 kDa. However, the actual molecular weight as observed by migration on SDS Page is Mr 22 kDa.

17.0

This recombinant protein was 0.2 µm filtered and lyophilized from 10 mM NaP, pH 7.5.

The lyophilized protein should be stored desiccated at -20°C. The reconstituted protein should be aliquoted into working volumes and stored at -20°C in a manual defrost freezer. Avoid Repeated Freeze Thaw Cycles.

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