Human Blood Dendritic Cell-Like B Cells Isolated by the 5G9 Monoclonal Antibody Reactive with a Novel 220-kDa Antigen

• Published in: The Journal of immunology (1950) 1999-08, Vol.163 (3), p.1354-1362
• Main Authors: Zhong, Rui-Kun, Donnenberg, Albert D, Zhang, Hai-Fan, Watkins, Simon, Zhou, Jie-Hua, Ball, Edward D
• Format: Article
• Language: English
• Subjects: Adult; Animals; Antibodies, Monoclonal - biosynthesis; Antibodies, Monoclonal - blood; Antibodies, Monoclonal - chemistry; Antigens, Surface - immunology; B-Lymphocyte Subsets - chemistry; B-Lymphocyte Subsets - cytology; B-Lymphocyte Subsets - immunology; Cells, Cultured; Dendritic Cells - chemistry; Dendritic Cells - cytology; Dendritic Cells - immunology; Female; Flow Cytometry; Humans; Immunohistochemistry; Immunomagnetic Separation; Isoantigens - immunology; Lymphocyte Activation - immunology; Lymphocyte Culture Test, Mixed; Mice; Mice, Inbred BALB C; Molecular Weight; Tumor Cells, Cultured
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.163.3.1354

We developed a murine IgG1 mAb, 5G9, following immunization of a BALB/c mouse with Daudi cells. By immunoprecipitation, 5G9 reacted with a 220-kDa Ag on Daudi cells, which reduced to four subunits (55, 65, 80, and 85 kDa). mAb 5G9 bound to 40-60% of peripheral blood B cells, weakly reacted with monocytes and granulocytes, and did not bind to erythrocytes, platelets, T cells, or NK cells. mAb 5G9 brightly stained scattered cells in human tonsil sections, which appeared to be dendritic cells (DC) by morphology. mAb 5G9 also stained scattered cells in cytospin slides of monocyte-derived DC with long, thin, beaded membrane processes, morphologically distinct from other monocyte-derived DC. Positive selection of blood mononuclear cells with mAb 5G9 and sheep anti-mouse IgG Dynabeads demonstrated an enriched population of DC. By flow cytometry analysis, these cells were CD19, CD20, CD22, CD40, CD44, CD83, CD86, IgD, and HLA-Dr positive and either kappa- or lambda-L chain positive. They did not express CD3, CD4, CD5, CD10, CD11b, CD13, CD25, CD56, CD14, CD33, or CD64. Isolated 5G9+ cells were potent APCs in allogeneic MLR, compared with 5G9- PBMC, 5G9- B cells, monocytes, and monocytes cultured in IL-4 and GM-CSF for 24 h. mAb 5G9 defines a novel peripheral blood cell with B cell phenotype and DC morphology and function: DC-like B cells. The significance of this cell in immune responses requires further study.