BAFF (B cell activation factor of the TNF family, also known as BLyS or TALL1) is a key survival factor for peripheral B cells. BAFF is a homotrimeric type II transmembrane protein that can be proteolytically processed by furin to be released as soluble cytokine (1). Soluble BAFF adopts the classical trimeric form of the TNF-family ligand. However, BAFF has the unique property among the TNF-ligand to assemble as a 60-mer (2). BAFF is mainly produced by innate immune cells such as neutrophils, monocytes, macrophages, dendritic cells, follicular dendritic cells. T cells, activated B cells, some malignant B cells and also non-lymphoid cells like astrocytes, synoviocytes and epithelial cells can also produce BAFF. BAFF binds three distinct receptors (BAFF-R, TACI and BCMA) expressed predominantly on B cells, although activated T cells also express BAFF-R. BAFF is a master regulator of peripheral B cell survival, and together with IL-6, promotes Ig class-switching and plasma cell differentiation (1).
Besides its major role in B cell biology, BAFF co-stimulates activated T cells. Deregulated expression of BAFF leads to autoimmune disorders in mice. In humans, elevated levels of soluble BAFF have been detected in the serum of patients with various autoimmune diseases (3), such as Sjögren’s syndrome (4), Rheumatoid Arthritis (RA) (5), Multiple sclerosis (MS) (6) and Systemic Lupus Erythematosus (SLE) (7). BAFF is also increased levels in some lymphoid cancers (8).
Sandwich type ELISA
B cell activation factor of the TNF family, BLyS, TALL1, TNFSF13B, TNFSF20, Tumor necrosis factor ligand superfamily member 13B
Principle of Method
This assay is a sandwich Enzyme Linked-Immunosorbent Assay (ELISA) for quantitative determination of human BAFF (BAFF) in serum, plasma and cell culture supernatant. A monoclonal antibody specific for BAFF has been precoated onto the 96-well microtiter plate. Standards (STD) and samples are pipetted into the wells for binding to the coated antibody. After extensive washing to remove unbound compounds, BAFF is recognized by the addition of a biotinylated monoclonal antibody specific for BAFF (DET). After removal of excess biotinylated antibody, streptavidine-peroxidase (STREP-HRP) is added. Following a final washing, peroxidase activity is quantified using the substrate 3,3’,5,5’-tetramethylbenzidine (TMB). The intensity of the color reaction is measured at 450 nm after acidification and is directly proportional to the concentration of BAFF in the samples.
Serum, Plasma and Cell Culture Supernatant
Serum and Plasma : ~3.33 µL (actual amount of sample loaded in well after dilution);
Calibration Range: 15.6 pg/ml – 500 pg/ml
Limit of Detection
Intra-assay (Within-Run) C.V.
Inter-assay (Run-to-Run) C.V.
References to Summary
- Cracking the BAFF code: F. Mackay & P. Schneider; Nat. Rev. Immunol. 9, 491 (2009)
- TACI, unlike BAFF-R, is solely activated by oligomeric BAFF and APRIL to support survival of activated B cells and plasmablasts: C. Bossen, et al.; Blood 111, 1004 (2009)
- BAFF: a local and systemic target in autoimmune diseases: I. Moisini & Davidson; Clin. Exp. Immunol. 158, 155 (2009)
- B-cell tolerance breakdown in Sjögren's syndrome: focus on BAFF: M.M. Varin, et al.; Autoimmun. Rev. 9, 604 (2010)
- Concentrations of BAFF correlate with autoantibody levels, clinical disease activity, and response to treatment in early rheumatoid arthritis: S. Bosello, et al.; Rheumatol. 35, 1256 (2008)
- A BAFF antagonist suppresses experimental autoimmune encephalomyelitis by targeting cell-mediated and humoral immune responses: N.D. Huntington, et al.; Immunol. 18, 1473 (2006)
- B lymphocyte stimulator overexpression in patients with systemic lupus erythematosus: longitudinal observations: W. Stohl, et al.; Arthritis Rheum. 48, 3475 (2003)
- Serum BAFF predicts prognosis better than APRIL in diffuse large B-cell lymphoma patients treated with rituximab plus CHOP chemotherapy: S.J. Kim, et al.; Eur. J. Haematol. 81, 177 (2008)