The CD5+ B-cell.
In the last two decades, many efforts have been made to better understand the biology of B-lymphoproliferative disorders through the knowledge of physiology and function of the postulated normal counterpart. The follicular mantle B-cells express a typical CD23+ IgM+ IgD+ phenotype and surround the germinal center area in secondary lymphoid organs. CD5+ B-cells with FM phenotype can be isolated from different sources and all share similar morphologic, phenotypic and functional features (small cells, scanty nucleus/cytoplasm ratio, unmutated VH genes, response to polyclonal activators but not to T independent antigens, production of "natural" antibodies). While the CD5+ B-cells predominate in fetal life, their number decreases with age. However, the CD5+ B-cells have been demonstrated to increase again in elderly both in man and mouse. This finding may explain the incidence of B-CLL and of MCL that are believed to represent the malignant transformation of the normal CD5+ B-cells, among elderly and middle aged individuals, respectively.
S. C. Oncologia Medica C, Istituto Nazionale per la Ricerca sul Cancro, IST, L.go Rosanna Benzi, n. 10, 16132 Genova, Italy. mariella.dono@istge.it
Mariella
M
Dono
Giannamaria
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Cerruti
Simona
S
Zupo
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D018956:CD5 Antigens / Q000276:immunology*; D015326:Gene Rearrangement, B-Lymphocyte, Heavy Chain / Q000276:immunology; D006801:Humans; D007072:Immunoglobulin D / Q000276:immunology; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000209:etiology / Q000276:immunology*; D020522:Lymphoma, Mantle-Cell / Q000209:etiology / Q000276:immunology*; D051379:Mice; D017455:Receptors, IgE / Q000276:immunology*
D018956:CD5 Antigens; D007072:Immunoglobulin D; D017455:Receptors, IgE