title: Antigen receptor triggered upregulation of CD86 and CD80 in human B cells: augmenting role of the CD21/CD19 co-stimulatory complex and IL-4.
abstract: The impact of BCR:CD21 co-engagement on B cell expression of molecules critical for T cell activation was investigated with receptor-specific mAbs conjugated to high MW dextran as stimulatory ligands. In the absence of IL-4, BCR:CD21 co-ligation augmented BCR-triggered CD86 only under conditions of very low BCR ligand dose or affinity, and CD80 was minimally induced by BCR and/or CD21 crosslinking. In the presence of IL-4, BCR:CD21 co-ligation augmented CD86 and CD80 expression under conditions of greater BCR engagement. However, with very high level BCR engagement, no bonus effect of BCR:CD21 crosslinking was observed. Co-ligation-promoted CD86 and CD80 expression was associated with heightened B cell activation of resting allogeneic T cells. The data suggest that co-clustering of BCR and the CD21/CD19 co-stimulatory complex following B cell engagement with C3d-bound microbial or self-antigens will enhance B cell recruitment of T cell help only when IL-4 is present and/or BCR engagement is very limiting.
authors.affiliation: Department of Rheumatology, Hospital for Joint Diseases, 301 E. 17th St., New York, NY 10003, USA. patricia.mongini@med.nyu.edu
authors.forename: Patricia K A
authors.initials: PK
authors.lastname: Mongini
authors.forename: Sonia
authors.initials: S
authors.lastname: Tolani
authors.forename: Rasem J
authors.initials: RJ
authors.lastname: Fattah
authors.forename: John K
authors.initials: JK
authors.lastname: Inman
mesh_terms: D000293:Adolescent; D015703:Antigens, CD / Q000502:physiology*; D018941:Antigens, CD19 / Q000502:physiology*; D001402:B-Lymphocytes / Q000276:immunology*; D018122:B7-1 Antigen / Q000502:physiology*; D051940:B7-2 Antigen; D002648:Child; D002675:Child, Preschool; D004306:Dose-Response Relationship, Immunologic; D006801:Humans; D015847:Interleukin-4 / Q000032:analysis / Q000096:biosynthesis / Q000502:physiology*; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins / Q000502:physiology*; D011947:Receptors, Antigen, B-Cell / Q000502:physiology*; D017464:Receptors, Complement 3d / Q000502:physiology*; D019948:Receptors, Interleukin-4; D013601:T-Lymphocytes / Q000276:immunology; D015854:Up-Regulation
chemical_list: D015703:Antigens, CD; D018941:Antigens, CD19; D018122:B7-1 Antigen; D051940:B7-2 Antigen; C497964:CD86 protein, human; D008562:Membrane Glycoproteins; D011947:Receptors, Antigen, B-Cell; D017464:Receptors, Complement 3d; D019948:Receptors, Interleukin-4; D015847:Interleukin-4