Specificity and Avidity of Donor MHC-Specific B Cells in Naive, Rejecting and Tolerant Mice
1Department of Surgery, University of Chicago, Chicago, IL, 2Merck, Boston, MA, 3Brigham and Women's Hospital, Boston, MA, 4Department of Microbiology, University of Alabama, Birmingham, AL
Meeting: 2022 American Transplant Congress
Abstract number: 1214
Keywords: Antibodies, B cells, IgG, Major histocompatibility complex (MHC)
Topic: Basic Science » Basic Science » 04 - B-cell / Antibody /Autoimmunity
Session Information
Session Name: B-cell / Antibody /Autoimmunity
Session Type: Poster Abstract
Date: Monday, June 6, 2022
Session Time: 7:00pm-8:00pm
Presentation Time: 7:00pm-8:00pm
Location: Hynes Halls C & D
*Purpose: Antibody-mediated rejection is recognized as an important mediator of graft loss in the clinic, and the induction of donor-specific B cell tolerance may contribute to long-term allograft acceptance. Studies from our laboratory used donor MHC Class I and II tetramers to track donor-specific B cells and demonstrate that they differentiate into germinal center (GC) B cells and antibody-secreting cells (ASC) in rejection, and donor MHC-specific B cells were prevented from differentiating into GC B cells and ASC during transplant tolerance. In this study, we confirmed the specificity of MHC tetramer capture approach and tested whether high-avidity of donor MHC-specific B cells was preferentially deleted in tolerant recipients.
*Methods: Using donor MHC Class II I-Ed specific tetramers to flow-sort individual B cells, we cloned the heavy and light chains of the B cell receptor (BCR) and expressed them in HEK293 human embryonic kidney cells as mouse IgG1 mAb.
*Results: Affinities were determined (KD50) by displacement of antibody binding or surface plasmon resonance, and that low and high-affinity mAbs were present at comparable frequencies in naïve, tolerant and acute rejecting mice. Furthermore, there was no significant difference in mutation rates of heavy chains from high or low-affinity clones, suggesting that high-affinity non-mutated anti-donor MHC B cell clones spontaneously arise. Interestingly, a feature of high-affinity clones was significantly shorter CDR3, a common feature of autoreactive B cells.
*Conclusions: Taken together, these studies confirm the specificity of MHC tetramers for identifying donor-specific B cells, and the absence of deletion of high-affinity clones in mice made tolerant to allografts with co-stimulation blockade.
To cite this abstract in AMA style:
Sayin I, Khiew S, Yin D, Sage P, Cavazzoni CB, King R, Chong A. Specificity and Avidity of Donor MHC-Specific B Cells in Naive, Rejecting and Tolerant Mice [abstract]. Am J Transplant. 2022; 22 (suppl 3). https://atcmeetingabstracts.com/abstract/specificity-and-avidity-of-donor-mhc-specific-b-cells-in-naive-rejecting-and-tolerant-mice/. Accessed November 11, 2024.« Back to 2022 American Transplant Congress