Antigen receptor triggered upregulation of CD86 and CD80 in human B cells: augmenting role of the CD21/CD19 co-stimulatory complex and IL-4

• Published in: Cellular immunology 2002-03, Vol.216 (1), p.50-64
• Main Authors: Mongini, Patricia K.A, Tolani, Sonia, Fattah, Rasem J, Inman, John K
• Format: Article
• Language: English
• Subjects: Adolescent; Antigens, CD - physiology; Antigens, CD19 - physiology; B cell; B-Lymphocytes - immunology; B7-1 Antigen - physiology; B7-2 Antigen; CD21; CD86; Cellular activation; Child; Child, Preschool; Co-stimulatory molecules; Complement; Dose-Response Relationship, Immunologic; Human; Humans; IL-4; Interleukin-4 - analysis; Interleukin-4 - biosynthesis; Interleukin-4 - physiology; Lymphocyte Activation; Membrane Glycoproteins - physiology; Receptors, Antigen, B-Cell - physiology; Receptors, Complement 3d - physiology; Receptors, Interleukin-4; T-Lymphocytes - immunology; Up-Regulation
• ISSN: 0008-8749; 1090-2163
• DOI: 10.1016/S0008-8749(02)00512-9

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.