Limits...
BAFF binds to the tumor necrosis factor receptor-like molecule B cell maturation antigen and is important for maintaining the peripheral B cell population.

Thompson JS, Schneider P, Kalled SL, Wang L, Lefevre EA, Cachero TG, MacKay F, Bixler SA, Zafari M, Liu ZY, Woodcock SA, Qian F, Batten M, Madry C, Richard Y, Benjamin CD, Browning JL, Tsapis A, Tschopp J, Ambrose C - J. Exp. Med. (2000)

Bottom Line: Although BCMA was previously localized to the Golgi apparatus, BCMA was found to be expressed on the surface of transfected cells and tonsillar B cells.A soluble form of BCMA, which inhibited the binding of BAFF to a B cell line, induced a dramatic decrease in the number of peripheral B cells when administered in vivo.These results are consistent with a role for BAFF in maintaining homeostasis of the B cell population.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Genetics, Biogen, Incorporated, Cambridge, Massachusetts 02142, USA.

ABSTRACT
The tumor necrosis factor (TNF) family member B cell activating factor (BAFF) binds B cells and enhances B cell receptor-triggered proliferation. We find that B cell maturation antigen (BCMA), a predicted member of the TNF receptor family expressed primarily in mature B cells, is a receptor for BAFF. Although BCMA was previously localized to the Golgi apparatus, BCMA was found to be expressed on the surface of transfected cells and tonsillar B cells. A soluble form of BCMA, which inhibited the binding of BAFF to a B cell line, induced a dramatic decrease in the number of peripheral B cells when administered in vivo. Moreover, culturing splenic cells in the presence of BAFF increased survival of a percentage of the B cells. These results are consistent with a role for BAFF in maintaining homeostasis of the B cell population.

Show MeSH

Related in: MedlinePlus

The extracellular domain of BCMA interacts with BAFF. (A) Human BCMA-Ig and various control TNFR-Ig molecules were mixed with Flag-tagged TNF ligands, immunoprecipitated (IP) with protein A Sepharose, and analyzed by Western blot (WB). Receptor-Ig is revealed with anti–human IgG (top), and coimmunoprecipitating ligands are detected using anti-Flag M2 antibody (bottom). α, anti-. (B) Interaction of BAFF with BCMA assayed by surface plasmon resonance (BIAcore). (C) BCMA-Ig binds stable 293 cell line expressing surface full-length BAFF. The wild-type 293 cells or a stable cell line expressing BAFF (reference 2) were stained with media containing similar amounts of BCMA-Ig, TNFR2-Ig, TRAILR2-Ig, or control media using PE-conjugated anti-hIgG1 (left and middle). The presence of surface BAFF was detected using an anti-hBAFF rat mAb, 43.9 (reference 2; right). (D) BCMA-Ig blocks BAFF binding to Raji cells. Various concentrations of either BCMA-Ig or LTβR-Ig were preincubated with Flag-BAFF, then added to Raji cells. BAFF binding was detected with the anti-Flag M2 antibody and analyzed by flow cytometry.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC1887706&req=5

Figure 1: The extracellular domain of BCMA interacts with BAFF. (A) Human BCMA-Ig and various control TNFR-Ig molecules were mixed with Flag-tagged TNF ligands, immunoprecipitated (IP) with protein A Sepharose, and analyzed by Western blot (WB). Receptor-Ig is revealed with anti–human IgG (top), and coimmunoprecipitating ligands are detected using anti-Flag M2 antibody (bottom). α, anti-. (B) Interaction of BAFF with BCMA assayed by surface plasmon resonance (BIAcore). (C) BCMA-Ig binds stable 293 cell line expressing surface full-length BAFF. The wild-type 293 cells or a stable cell line expressing BAFF (reference 2) were stained with media containing similar amounts of BCMA-Ig, TNFR2-Ig, TRAILR2-Ig, or control media using PE-conjugated anti-hIgG1 (left and middle). The presence of surface BAFF was detected using an anti-hBAFF rat mAb, 43.9 (reference 2; right). (D) BCMA-Ig blocks BAFF binding to Raji cells. Various concentrations of either BCMA-Ig or LTβR-Ig were preincubated with Flag-BAFF, then added to Raji cells. BAFF binding was detected with the anti-Flag M2 antibody and analyzed by flow cytometry.

Mentions: TNF receptor family members are generally type I proteins with a leader sequence and a cysteine-rich extracellular domain. The extracellular domains are organized as a series of alternating A and B modules, which are stabilized by internal disulfide bridges 17. A single C module, not involved in ligand binding, is found in the fourth cysteine repeat of TNFRI 17. In a previous study, BAFF failed to bind to 16 members of the TNF receptor family 2. Subsequently, an additional candidate receptor for BAFF was identified, termed B cell maturation antigen 10. BCMA appears to be distantly related to the TNF receptor family, because it is devoid of a signal sequence and contains a single A and one C module instead of multiple A and B modules 10. However, the expression pattern of this atypical receptor in mature B cells prompted us to examine its interaction with BAFF 89. To this end, the extracellular domain of human BCMA was expressed as a human IgG1 fusion protein and was targeted to the secretory pathway with an added signal peptide. BCMA-hIgG1 (BCMA-Ig) fusion protein immunoprecipitated both recombinant human and murine BAFF very efficiently, but not five other TNF ligands (CD40L, RANKL, CD30L, LIGHT, and TNF-α) which, however, interacted with their respective receptors in control immunoprecipitations (Fig. 1 A). When the interaction was tested in another format using surface plasmon resonance (BIAcore) analysis, similar results were obtained, and both murine and human BAFF exhibited a significant affinity for human BCMA-Ig but not for LTβR-Ig (Fig. 1 B). In addition, BCMA-Ig interacted with membrane-bound BAFF expressed in 293 cells (Fig. 1 C), and in a dose-dependent manner specifically blocked the interaction of BAFF with Raji B cells (Fig. 1 D). Thus, the short extracellular domain of BCMA is sufficient for high-affinity binding to BAFF, and there is no species barrier for the murine BAFF–human BCMA interaction. The BAFF–BCMA interaction is presently unique in the family, as it involves only two modules, one predicted to be of the C type. In the two cases where the crystal structure of the trimeric ligand–receptor complex is known (LTα–TNFR1 and TRAIL–TRAILR2), the contacts involved in the interaction have been shown to involve one B and two A modules 181920.


BAFF binds to the tumor necrosis factor receptor-like molecule B cell maturation antigen and is important for maintaining the peripheral B cell population.

Thompson JS, Schneider P, Kalled SL, Wang L, Lefevre EA, Cachero TG, MacKay F, Bixler SA, Zafari M, Liu ZY, Woodcock SA, Qian F, Batten M, Madry C, Richard Y, Benjamin CD, Browning JL, Tsapis A, Tschopp J, Ambrose C - J. Exp. Med. (2000)

The extracellular domain of BCMA interacts with BAFF. (A) Human BCMA-Ig and various control TNFR-Ig molecules were mixed with Flag-tagged TNF ligands, immunoprecipitated (IP) with protein A Sepharose, and analyzed by Western blot (WB). Receptor-Ig is revealed with anti–human IgG (top), and coimmunoprecipitating ligands are detected using anti-Flag M2 antibody (bottom). α, anti-. (B) Interaction of BAFF with BCMA assayed by surface plasmon resonance (BIAcore). (C) BCMA-Ig binds stable 293 cell line expressing surface full-length BAFF. The wild-type 293 cells or a stable cell line expressing BAFF (reference 2) were stained with media containing similar amounts of BCMA-Ig, TNFR2-Ig, TRAILR2-Ig, or control media using PE-conjugated anti-hIgG1 (left and middle). The presence of surface BAFF was detected using an anti-hBAFF rat mAb, 43.9 (reference 2; right). (D) BCMA-Ig blocks BAFF binding to Raji cells. Various concentrations of either BCMA-Ig or LTβR-Ig were preincubated with Flag-BAFF, then added to Raji cells. BAFF binding was detected with the anti-Flag M2 antibody and analyzed by flow cytometry.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC1887706&req=5

Figure 1: The extracellular domain of BCMA interacts with BAFF. (A) Human BCMA-Ig and various control TNFR-Ig molecules were mixed with Flag-tagged TNF ligands, immunoprecipitated (IP) with protein A Sepharose, and analyzed by Western blot (WB). Receptor-Ig is revealed with anti–human IgG (top), and coimmunoprecipitating ligands are detected using anti-Flag M2 antibody (bottom). α, anti-. (B) Interaction of BAFF with BCMA assayed by surface plasmon resonance (BIAcore). (C) BCMA-Ig binds stable 293 cell line expressing surface full-length BAFF. The wild-type 293 cells or a stable cell line expressing BAFF (reference 2) were stained with media containing similar amounts of BCMA-Ig, TNFR2-Ig, TRAILR2-Ig, or control media using PE-conjugated anti-hIgG1 (left and middle). The presence of surface BAFF was detected using an anti-hBAFF rat mAb, 43.9 (reference 2; right). (D) BCMA-Ig blocks BAFF binding to Raji cells. Various concentrations of either BCMA-Ig or LTβR-Ig were preincubated with Flag-BAFF, then added to Raji cells. BAFF binding was detected with the anti-Flag M2 antibody and analyzed by flow cytometry.
Mentions: TNF receptor family members are generally type I proteins with a leader sequence and a cysteine-rich extracellular domain. The extracellular domains are organized as a series of alternating A and B modules, which are stabilized by internal disulfide bridges 17. A single C module, not involved in ligand binding, is found in the fourth cysteine repeat of TNFRI 17. In a previous study, BAFF failed to bind to 16 members of the TNF receptor family 2. Subsequently, an additional candidate receptor for BAFF was identified, termed B cell maturation antigen 10. BCMA appears to be distantly related to the TNF receptor family, because it is devoid of a signal sequence and contains a single A and one C module instead of multiple A and B modules 10. However, the expression pattern of this atypical receptor in mature B cells prompted us to examine its interaction with BAFF 89. To this end, the extracellular domain of human BCMA was expressed as a human IgG1 fusion protein and was targeted to the secretory pathway with an added signal peptide. BCMA-hIgG1 (BCMA-Ig) fusion protein immunoprecipitated both recombinant human and murine BAFF very efficiently, but not five other TNF ligands (CD40L, RANKL, CD30L, LIGHT, and TNF-α) which, however, interacted with their respective receptors in control immunoprecipitations (Fig. 1 A). When the interaction was tested in another format using surface plasmon resonance (BIAcore) analysis, similar results were obtained, and both murine and human BAFF exhibited a significant affinity for human BCMA-Ig but not for LTβR-Ig (Fig. 1 B). In addition, BCMA-Ig interacted with membrane-bound BAFF expressed in 293 cells (Fig. 1 C), and in a dose-dependent manner specifically blocked the interaction of BAFF with Raji B cells (Fig. 1 D). Thus, the short extracellular domain of BCMA is sufficient for high-affinity binding to BAFF, and there is no species barrier for the murine BAFF–human BCMA interaction. The BAFF–BCMA interaction is presently unique in the family, as it involves only two modules, one predicted to be of the C type. In the two cases where the crystal structure of the trimeric ligand–receptor complex is known (LTα–TNFR1 and TRAIL–TRAILR2), the contacts involved in the interaction have been shown to involve one B and two A modules 181920.

Bottom Line: Although BCMA was previously localized to the Golgi apparatus, BCMA was found to be expressed on the surface of transfected cells and tonsillar B cells.A soluble form of BCMA, which inhibited the binding of BAFF to a B cell line, induced a dramatic decrease in the number of peripheral B cells when administered in vivo.These results are consistent with a role for BAFF in maintaining homeostasis of the B cell population.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Genetics, Biogen, Incorporated, Cambridge, Massachusetts 02142, USA.

ABSTRACT
The tumor necrosis factor (TNF) family member B cell activating factor (BAFF) binds B cells and enhances B cell receptor-triggered proliferation. We find that B cell maturation antigen (BCMA), a predicted member of the TNF receptor family expressed primarily in mature B cells, is a receptor for BAFF. Although BCMA was previously localized to the Golgi apparatus, BCMA was found to be expressed on the surface of transfected cells and tonsillar B cells. A soluble form of BCMA, which inhibited the binding of BAFF to a B cell line, induced a dramatic decrease in the number of peripheral B cells when administered in vivo. Moreover, culturing splenic cells in the presence of BAFF increased survival of a percentage of the B cells. These results are consistent with a role for BAFF in maintaining homeostasis of the B cell population.

Show MeSH
Related in: MedlinePlus