title: Relative expression of surface IgM, IgD and the Ig-associating alpha(mb-1) and beta(B-29) polypeptide chains.
abstract: Membrane immunoglobulins are associated with a transmembrane disulphide-linked heterodimer composed of an alpha-chain (mb-1) and a beta-chain (B-29). The relative surface expression of all of the polypeptide chains comprising the Ig-alpha beta complex has been investigated using surface labelling coprecipitation analysis and two-colour flow cytometric analysis. The main conclusions are that mb-1 and B-29 are B-cell surface markers on immature and mature B cells, and that all components of the surface Ig-alpha beta complex are expressed in stoichiometrically equivalent amounts. Thus the complex was quantitatively precipitated from digitonin lysates of 125I-surface-labelled cells with anti-B-29, anti-mb-1 or anti-Ig. Secondly, by two-colour FACS analysis there was a proportionality between the relative amounts of cell surface mb-1 or B-29 and surface IgM or IgD, but not other B-cell markers (class II, B220, FcR gamma, FcR epsilon). Finally there was an insignificant number of B cells expressing membrane Ig without alpha- and beta-chains, and vice versa. Thus there appears to be a closely controlled relative synthesis and surface expression of all components of the B-cell receptor complex.
authors.affiliation: Institute for Animal Health, Pirbright, Surrey, U.K.
authors.forename: R M
authors.initials: RM
authors.lastname: Parkhouse
authors.forename: G
authors.initials: G
authors.lastname: Preece
authors.forename: R
authors.initials: R
authors.lastname: Sutton
authors.forename: J L
authors.initials: JL
authors.lastname: Cordell
authors.forename: D Y
authors.initials: DY
authors.lastname: Mason
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology; D015153:Blotting, Western; D001853:Bone Marrow / Q000276:immunology; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D007072:Immunoglobulin D / Q000032:analysis*; D007075:Immunoglobulin M / Q000032:analysis*; D008213:Lymphocyte Activation / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008808:Mice, Inbred CBA; D010455:Peptides / Q000276:immunology; D011947:Receptors, Antigen, B-Cell / Q000032:analysis*; D013154:Spleen / Q000276:immunology
chemical_list: D007072:Immunoglobulin D; D007075:Immunoglobulin M; D010455:Peptides; D011947:Receptors, Antigen, B-Cell