Human blood dendritic cell-like B cells isolated by the 5G9 monoclonal antibody reactive with a novel 220-kDa antigen.
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.
Zhong
R K
RK
Department of Medicine, School of Medicine, University of California at San Diego, La Jolla 92093, USA.
Donnenberg
A D
AD
Zhang
H F
HF
Watkins
S
S
Zhou
J H
JH
Ball
E D
ED
D000328:Adult; D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000097:blood* / Q000737:chemistry; D000954:Antigens, Surface / Q000276:immunology*; D016175:B-Lymphocyte Subsets / Q000737:chemistry / Q000166:cytology / Q000276:immunology*; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000737:chemistry / Q000166:cytology / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D018189:Immunomagnetic Separation; D007519:Isoantigens / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology; D007959:Lymphocyte Culture Test, Mixed; D051379:Mice; D008807:Mice, Inbred BALB C; D008970:Molecular Weight; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D007519:Isoantigens