Negligible Class II MHC Presentation of B Cell Receptor-Derived Peptides by High Density Resting B Cells

• Published in: The Journal of immunology (1950) 2002-04, Vol.168 (8), p.3865-3873
• Main Authors: Snyder, Christopher M, Zhang, Xianghua, Wysocki, Lawrence J
• Format: Article
• Language: English
• Subjects: Animals; Antigen Presentation; Antigen-Presenting Cells - cytology; Antigen-Presenting Cells - immunology; Antigen-Presenting Cells - metabolism; B-Lymphocyte Subsets - cytology; B-Lymphocyte Subsets - immunology; B-Lymphocyte Subsets - metabolism; Cell Count; Cell Culture Techniques; Cells, Cultured; Clonal Anergy; Coculture Techniques; Histocompatibility Antigens Class II - metabolism; Immunodominant Epitopes - biosynthesis; Immunodominant Epitopes - metabolism; Immunoglobulin Heavy Chains - metabolism; Immunoglobulin kappa-Chains - biosynthesis; Immunoglobulin kappa-Chains - metabolism; Immunoglobulin Variable Region - metabolism; Immunophenotyping; Interphase - immunology; Lymphocyte Activation; Lymphocyte Count; Mice; Mice, Inbred A; Mice, Inbred C57BL; Mice, Transgenic; Peptide Fragments - immunology; Peptide Fragments - metabolism; Receptors, Antigen, B-Cell - metabolism; T-Lymphocytes - immunology
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.168.8.3865

Resting B lymphocytes have been credited with inducing T cell tolerance to Ig-derived and monovalent self-Ags that are internalized via the B cell receptor (BCR). These conclusions are predicated upon the assumptions that resting B cells display BCR-associated peptides in class II MHC and that the cells remain quiescent during the course of experimental manipulation. To determine whether resting B cells display BCR-associated epitopes in class II MHC, we devised a sensitive assay that averted potential activation of B cells by Ag and minimized activation by prolonged culture. Ex vivo, Percoll-fractionated B cells expressing a kappa transgene encoding a T cell epitope were cultured with a reactive T cell hybridoma for 12 h. Whereas low density, LPS-activated, and BCR-activated B cells elicited significant IL-2 from the T cell hybridoma, resting high density B cells did not. Parallel results were obtained with normal B cells expressing a second epitope encoded by an endogenous V(H) gene. Anergic B cells, which are uniformly low density, also significantly stimulated the T cell hybridoma. Finally, longer culture periods with normal B cells resulted in a higher degree of B cell activation and significant stimulation of reactive T cell hybridomas. Our results provide evidence that activation of B cells profoundly enhances the processing and presentation of BCR-associated Ags.