: A major determinant in the development, selection and differentiation of B lymphocytes is the B cell antigen receptor (BCR) whose antibody variable regions recognize antigen and whose signaling unit (the Igalpha/Beta heterodimer transmits signals into the interior of the cell. Signaling pathways activated by Igalpha/Beta cytoplasmic tails control the response of the cells to antigenic selection including tolerance induction by antigen to avoid autoimmunity and antibody responses to pathogens. BCR signaling also seems to be required for mature B cell survival. Signaling through the cytoplasmic tails of Igalpha/Beta requires phosphorylation of tyrosine-based activation motifs termed ITAMs. However, there is evidence mainly from work on cell lines that other conserved targets of phosphorylation in these tails including serine and threonine residues also contribute to signal transduction. The present proposal aims at defining the role of these residues in B cell development and activation in the in vivo context, using targeted mutagenesis in the mouse. We will similarly analyze the roles of the cytoplasmic tails in the maintenance of mature B cells and their interplay with B-cell activation factor mediated survival, using systems of inducible gene targeting. Knowledge about the control of B cell survival is critical for an understanding of B cell homeostasis and therapeutic intervention in B cell-mediated autoimmunity and B cell lymphoma growth. In a final part of the proposal, we will address to which extent the differentiation of B cells into the B-1 and B-2 subsets is driven by BCR specificities which are unequally distributed between the two subsets. B-1 cells are thought to play a major role in natural immune defense and to be prone to autoantibody production, whereas B-2 cells are the major players in adaptive antibody responses. We will use a genetic switch allowing the cells to switch in vivo from the expression of a B-I typical to a B-2-typical BCR and vice versa, to determine to which extent the B-1 and B-2 phenotypes represent distinct states of activation as opposed to being determined by distinct developmental programs. This will be complemented by an attempt to switch mature B-2 ceils to a B-1 phenotype by induced inactivation of SHP- 1 phosphatase whose inactivation in B cell progenitors leads to near-exclusive production of B- 1 cells
| Degn, S E; Alicot, E; Carroll, M C (2018) B cell tolerance to epidermal ribonuclear-associated neo-autoantigen in vivo. Clin Exp Immunol 191:151-165 |
| Degn, Søren E; van der Poel, Cees E; Firl, Daniel J et al. (2017) Clonal Evolution of Autoreactive Germinal Centers. Cell 170:913-926.e19 |
| Otipoby, Kevin L; Waisman, Ari; Derudder, Emmanuel et al. (2015) The B-cell antigen receptor integrates adaptive and innate immune signals. Proc Natl Acad Sci U S A 112:12145-50 |
| Heesters, Balthasar A; Myers, Riley C; Carroll, Michael C (2014) Follicular dendritic cells: dynamic antigen libraries. Nat Rev Immunol 14:495-504 |
| Woodruff, Matthew C; Heesters, Balthasar A; Herndon, Caroline N et al. (2014) Trans-nodal migration of resident dendritic cells into medullary interfollicular regions initiates immunity to influenza vaccine. J Exp Med 211:1611-21 |
| Heesters, Balthasar A; Das, Abhishek; Chatterjee, Priyadarshini et al. (2014) Do follicular dendritic cells regulate lupus-specific B cells? Mol Immunol 62:283-8 |
| Kreslavsky, Taras; Kim, Hye-Jung; Koralov, Sergei B et al. (2013) Negative selection, not receptor editing, is a physiological response of autoreactive thymocytes. J Exp Med 210:1911-8 |
| Heesters, Balthasar A; Chatterjee, Priyadarshini; Kim, Young-A et al. (2013) Endocytosis and recycling of immune complexes by follicular dendritic cells enhances B cell antigen binding and activation. Immunity 38:1164-75 |
| Sander, Sandrine; Calado, Dinis P; Srinivasan, Lakshmi et al. (2012) Synergy between PI3K signaling and MYC in Burkitt lymphomagenesis. Cancer Cell 22:167-79 |
| Ko, Myunggon; Bandukwala, Hozefa S; An, Jungeun et al. (2011) Ten-Eleven-Translocation 2 (TET2) negatively regulates homeostasis and differentiation of hematopoietic stem cells in mice. Proc Natl Acad Sci U S A 108:14566-71 |
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