CD8αα intraepithelial lymphocytes arise from two main thymic precursors

Thymic progenitors of TCRαβ+ CD8αα intestinal intraepithelial lymphocytes require RasGRP1 for development

Strong T cell receptor (TCR) signaling largely induces cell death during thymocyte development, whereas weak TCR signals induce positive selection. However, some T cell lineages require strong TCR signals for differentiation through a process termed agonist selection. The signaling relationships that underlie these three fates are unknown. RasGRP1 is a Ras activator required to transmit weak TC...

c-Myc controls the development of CD8 TCR intestinal intraepithelial lymphocytes from thymic precursors by regulating IL-15–dependent survival

The murine gut epithelium contains a large population of thymus-derived intraepithelial lymphocytes (IELs), including both conventional CD4 and CD8 T cells (expressing T-cell receptor [TCR ]) and unconventional CD8 T cells (expressing either TCR or TCR ). Whereas conventional IELs are widely accepted to arise from recirculation of activated CD4 and CD8 T cells from the secondary lymphoid organs...

Lactobacillus reuteri induces gut intraepithelial CD4+CD8αα+ T cells.

The small intestine contains CD4+CD8αα+ double-positive intraepithelial lymphocytes (DP IELs), which originate from intestinal CD4+ T cells through down-regulation of the transcription factor Thpok and have regulatory functions. DP IELs are absent in germ-free mice, which suggests that their differentiation depends on microbial factors. We found that DP IEL numbers in mice varied in different v...

Peripheral CD4+ lymphocytes derived from fetal versus adult thymic precursors differ phenotypically and functionally.

There is growing evidence that the differentiation processes in the fetal and adult thymus are not identical. However, there is little information on whether these developmental differences influence the properties of mature cells that exit the thymus and seed peripheral lymphoid organs. We have addressed this issue by comparing the development of Ag-specific Th1/Th2 function by fetal vs adult ...

Regulatory T Lymphocytes from Precursors Epithelium Enhance Positive Selection of Agonist Ligands Expressed by Thymic