BACKGROUND: BB1 is a basophil-specific mAb (Lab Invest 1999;79:27-38). The identity of the corresponding antigen has not been determined, but it gives a granular appearance on staining and is secreted on activation of basophils. OBJECTIVE: We sought to further characterize the basophilspecific antigen identified by BB1. METHODS: Intracellular localization was determined by flow cytometry and by immunogold labeling and electron microscopy. Physical chemical properties were investigated by gel filtration chromatography and preparative isoelectric focusing. RESULTS: In flow cytometry, permeabilization of cells increased immunofluorescence 100-fold, confirming the predominantly intracellular localization of the antigen. It was further localized to the secretory granules by immunoelectron microscopy. Double labeling with a CD63-specific antibody demonstrated selective binding of BB1 to the granule matrix. Gel filtration chromatography indicated that the antigen is secreted as a complex of approximately 5 x 10(6) d, which was well resolved from the 210-kd supramolecular complex containing tryptase. The antigen was degraded by pronase. Isoelectric focusing indicated a highly basic protein with an isoelectric point of 9.6. CONCLUSION: With its granule localization, release on cell activation, and unique properties, the antigen identified by BB1 could be a novel mediator of allergic disease. We propose the name basogranulin for this novel basophil-specific protein.
BACKGROUND:BB1 is a basophil-specific mAb (Lab Invest 1999;79:27-38). The identity of the corresponding antigen has not been determined, but it gives a granular appearance on staining and is secreted on activation of basophils. OBJECTIVE: We sought to further characterize the basophilspecific antigen identified by BB1. METHODS: Intracellular localization was determined by flow cytometry and by immunogold labeling and electron microscopy. Physical chemical properties were investigated by gel filtration chromatography and preparative isoelectric focusing. RESULTS: In flow cytometry, permeabilization of cells increased immunofluorescence 100-fold, confirming the predominantly intracellular localization of the antigen. It was further localized to the secretory granules by immunoelectron microscopy. Double labeling with a CD63-specific antibody demonstrated selective binding of BB1 to the granule matrix. Gel filtration chromatography indicated that the antigen is secreted as a complex of approximately 5 x 10(6) d, which was well resolved from the 210-kd supramolecular complex containing tryptase. The antigen was degraded by pronase. Isoelectric focusing indicated a highly basic protein with an isoelectric point of 9.6. CONCLUSION: With its granule localization, release on cell activation, and unique properties, the antigen identified by BB1 could be a novel mediator of allergic disease. We propose the name basogranulin for this novel basophil-specific protein.
Authors: Jeanette Grundström; Jenny M Reimer; Sofia E Magnusson; Gunnar Nilsson; Sara Wernersson; Lars Hellman Journal: PLoS One Date: 2012-10-31 Impact factor: 3.240
Authors: Anm Nazmul H Khan; Tiffany R Emmons; Jerry T Wong; Emad Alqassim; Kelly L Singel; Jaron Mark; Brandon E Smith; Joseph D Tario; Kevin H Eng; Kirsten B Moysich; Kunle Odunsi; Scott I Abrams; Brahm H Segal Journal: Cancer Immunol Res Date: 2020-04-01 Impact factor: 12.020
Authors: Dean D Metcalfe; Ruby Pawankar; Steven J Ackerman; Cem Akin; Frederic Clayton; Franco H Falcone; Gerald J Gleich; Anne-Marie Irani; Mats W Johansson; Amy D Klion; Kristin M Leiferman; Francesca Levi-Schaffer; Gunnar Nilsson; Yoshimichi Okayama; Calman Prussin; John T Schroeder; Lawrence B Schwartz; Hans-Uwe Simon; Andrew F Walls; Massimo Triggiani Journal: World Allergy Organ J Date: 2016-02-11 Impact factor: 4.084