TY - JOUR
T1 - A role for intrathymic B cells in the generation of natural regulatory T cells
AU - Walters, Stacey N.
AU - Webster, Kylie E.
AU - Daley, Stephen
AU - Grey, Shane T.
PY - 2014/7/1
Y1 - 2014/7/1
N2 - B cells inhabit the normal human thymus, suggesting a role in T cell selection. In this study, we report that B cells can modulate thymic production of CD4+ Foxp3+ T cells (regulatory T cells [Tregs]). Mice with transgenic expression of BAFF (BAFF-Tg) harbor increased numbers of Helios+Foxp3+ thymic Tregs and, similar to some human autoimmune conditions, also exhibit increased numbers of B cells colonizing the thymus. Distinct intrathymic B cell subpopulations were identified, namely B220+, IgM+, CD23hi, CD21int cells; B220+, IgM+, CD23lo, CD21lo cells; and a population of B220+, IgM+, CD23lo, CD21hi cells. Anatomically, CD19+ B cells accumulated in the thymic medulla region juxtaposed to Foxp3+ T cells. These intrathymic B cells engender Tregs. Indeed, thymic Treg development was diminished in both B cell-deficient BAFF-Tg chimeras, but also B cell- deficient wild-type chimeras. B cell Ag capture and presentation are critical in vivo events for Treg development. In the absence of B cell surface MHC class II expression, thymic expansion of BAFF-Tg Tregs was lost. Further to this, expansion of Tregs did not occur in BAFF-Tg/Ig hen egg lysozyme BCR chimeras, demonstrating a requirement for Ag specificity. Thus, we present a mechanism whereby intrathymic B cells, through the provision of cognate help, contribute to the shaping of the Treg repertoire.
AB - B cells inhabit the normal human thymus, suggesting a role in T cell selection. In this study, we report that B cells can modulate thymic production of CD4+ Foxp3+ T cells (regulatory T cells [Tregs]). Mice with transgenic expression of BAFF (BAFF-Tg) harbor increased numbers of Helios+Foxp3+ thymic Tregs and, similar to some human autoimmune conditions, also exhibit increased numbers of B cells colonizing the thymus. Distinct intrathymic B cell subpopulations were identified, namely B220+, IgM+, CD23hi, CD21int cells; B220+, IgM+, CD23lo, CD21lo cells; and a population of B220+, IgM+, CD23lo, CD21hi cells. Anatomically, CD19+ B cells accumulated in the thymic medulla region juxtaposed to Foxp3+ T cells. These intrathymic B cells engender Tregs. Indeed, thymic Treg development was diminished in both B cell-deficient BAFF-Tg chimeras, but also B cell- deficient wild-type chimeras. B cell Ag capture and presentation are critical in vivo events for Treg development. In the absence of B cell surface MHC class II expression, thymic expansion of BAFF-Tg Tregs was lost. Further to this, expansion of Tregs did not occur in BAFF-Tg/Ig hen egg lysozyme BCR chimeras, demonstrating a requirement for Ag specificity. Thus, we present a mechanism whereby intrathymic B cells, through the provision of cognate help, contribute to the shaping of the Treg repertoire.
UR - http://www.scopus.com/inward/record.url?scp=84903625200&partnerID=8YFLogxK
U2 - 10.4049/jimmunol.1302519
DO - 10.4049/jimmunol.1302519
M3 - Article
SN - 0022-1767
VL - 193
SP - 170
EP - 176
JO - Journal of Immunology
JF - Journal of Immunology
IS - 1
ER -