title: Feedback suppression of B cell colony formation in healthy individuals.
abstract: Proliferation and differentiation of B cells has been extensively studied and the study of feedback suppression of B cell proliferation has been limited to humoral factors. However, very little is known about feedback suppression of B cell proliferation by cellular influences. We have previously reported on the role of T cells and their subsets on B cell proliferation in that we did not observe suppression of B cell colony growth by T cells. We now report on the role of B cells in limiting B cell proliferation. B cell colonies were grown in methyl cellulose for either 3 days or 5-6 days utilizing 2 x 10(5) T cells irradiated with 9,000 rads, and 2 x 10(5) B cells. The B cells were then obtained from these colonies and increasing numbers of cells were added to fresh autologous B cells that were further cultured for 5 days to form new B cell colonies. At the end of this period, B cell colony numbers were determined. Our data show that addition of CD19- and CD20- positive B cells recovered from mature colonies after 5 days to fresh B cells suppressed further B cell colony growth in all cases tested, whereas addition of CD19-positive B cells recovered from immature colonies after 3 days of culture did not suppress further B cell colony growth. Elimination of CD 19- or CD20-positive cells with monoclonal antibody to CD19 and complement or by the technique of panning enhanced colony growth. Supernatants obtained from B cell colonies did not suppress B cell colony formation. Our data suggest that there is feedback suppression of normal progenitor B cell proliferation by constituent B cells and that this effect develops during maturation of colonies during the growth phase.
authors.affiliation: Department of Medicine, Camp Hill Hospital, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: L A
authors.initials: LA
authors.lastname: Fernandez
authors.forename: J M
authors.initials: JM
authors.lastname: Macsween
authors.forename: D A
authors.initials: DA
authors.lastname: Robson
mesh_terms: D018941:Antigens, CD19 / Q000378:metabolism; D018951:Antigens, CD20 / Q000378:metabolism; D001402:B-Lymphocytes / Q000166:cytology* / Q000276:immunology*; D002454:Cell Differentiation; D002455:Cell Division; D003114:Colony-Forming Units Assay; D005246:Feedback; D006801:Humans; D066298:In Vitro Techniques
chemical_list: D018941:Antigens, CD19; D018951:Antigens, CD20