title: 4IgB7-H3 is the major isoform expressed on immunocytes as well as malignant cells.
abstract: Human B7-H3, a novel member of B7 family, has two isoforms (2IgB7-H3 and 4IgB7-H3). As costimulatory functions of both isoforms are not clarified, there has been much discussion on their expression patterns, T-cell responses, etc. This study generated two specific mouse anti-human 2IgB7-H3 monoclonal antibodies (mAbs) (7D7 and 10F1), whose specificities are quite different from those of the available B7-H3 mAb (21D4) by competition assay. The use of antibodies indicated that B7-H3 was found to have different expression patterns on monocyte-derived dendritic cells, that is the isoform 2IgB7-H3 is tended to express on immature dendritic cells (iDCs), whereas 4IgB7-H3 could be detected in the whole process of maturation of dendritic cells. The isoform 4IgB7-H3 was shown in the immunohistochemistry assay to be more widely expressed than 2IgB7-H3 in human benign and malignant hepatic tissues. Furthermore, flow cytometry and reverse transcription-polymerase chain reaction indicated that 4IgB7-H3 rather than 2IgB7-H3 was the major isoform on many human tumor cell lines. In addition, both 2IgB7-H3- and 4IgB7-H3-transfected cells could promote T-cell proliferation, which could be blocked by 7D7 mAb. These two novel antibodies may shed light on the function of the two B7-H3 isoforms.
authors.affiliation: Institute of Biotechnology and Clinical Immunology Research Laboratory of Jiangsu Province, Soochow University, Suzhou, China.
authors.forename: Y-H
authors.initials: YH
authors.lastname: Zhou
authors.forename: Y-J
authors.initials: YJ
authors.lastname: Chen
authors.forename: Z-Y
authors.initials: ZY
authors.lastname: Ma
authors.forename: L
authors.initials: L
authors.lastname: Xu
authors.forename: Q
authors.initials: Q
authors.lastname: Wang
authors.forename: G-B
authors.initials: GB
authors.lastname: Zhang
authors.forename: F
authors.initials: F
authors.lastname: Xie
authors.forename: Y
authors.initials: Y
authors.lastname: Ge
authors.forename: X-F
authors.initials: XF
authors.lastname: Wang
authors.forename: X-G
authors.initials: XG
authors.lastname: Zhang
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000502:physiology; D015703:Antigens, CD / Q000096:biosynthesis* / Q000235:genetics* / Q000502:physiology; D060887:B7 Antigens; D002454:Cell Differentiation / Q000276:immunology; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D018920:Coculture Techniques; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology* / Q000378:metabolism*; D006801:Humans; D008113:Liver Neoplasms / Q000276:immunology* / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D020033:Protein Isoforms / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology; D011971:Receptors, Immunologic / Q000096:biosynthesis* / Q000235:genetics* / Q000502:physiology
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D060887:B7 Antigens; C423237:CD276 protein, human; D020033:Protein Isoforms; D011971:Receptors, Immunologic