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Establishment of a Monoclonal Antibody Which Co-Stimulates the Proliferation of B Lymphocytes in vitro
Satoshi Kataoka*†, Jun Nomura†, Seiji Inui† and Nobuo Sakaguchi†
*Department of Oral and Maxillofacial Surgery, and †Department of Immunology, Faculty of Medicine, Tottori University, Yonago 683, Japan
Stimulation of co-stimulatory molecules for B cell proliferation is potentially an important method to enhance or support the efficient immune response. To study novel B cell stimulatory molecules, we prepared a monoclonal antibody (mAb) which recognizes a B cell differentiation antigen named LB227 by immunizing rats with activated murine spleen B cells in vitro by lipoplysaccharide (LPS). It immunoprecipitates a 45-kDa membrane protein expressed on the surface of B lineage cells and some of T cells in murine spleen. It stains murine cell lines of pro-B cell, pre-B cell, immature B cell and mature B cell. LB227 alone does not induce any increase of B cell proliferation, however it enhances B cell proliferation in vitro when added together with IL-4. Responding spleen cells to the stimulation with LB227 mAb have a characteristic of B220+ sIgM+ B cells, suggesting that LB227 would be one of useful mAbs for the B cell stimulants which may enhance the immune response in vivo.
Key words: co-stimulatory molecules; B cell growth; differentiation antigen; monoclonal antibody.