GPR18 is required for a normal CD8?? intestinal intraepithelial lymphocyte compartment.

ABSTRACT: Intraepithelial lymphocytes (IELs) play an important role in maintaining the physiology of the small intestine. The majority of mouse IELs express CD8?? and are either ?? or ?? T cells. Although the development and homing of CD8?? IELs have been studied in some detail, the factors controlling their homeostasis and positioning are incompletely understood. Here we demonstrate that G protein-coupled receptor 18 (GPR18) is abundantly expressed in CD8?? IELs and that mice lacking this orphan receptor have reduced numbers of ??T IELs. Mixed bone marrow chimera experiments reveal a markedly reduced contribution of GPR18-deficient cells to the CD8?? IEL compartment and a reduction in the CD8?? T cell subset. These defects could be rescued by transduction with a GPR18-expressing retrovirus. The GPR18-deficient ??T IELs that remained in mixed chimeras had elevated Thy1, and there were less granzyme B(+) and V?7(+) cells, indicating a greater reduction in effector-type cells. Flow cytometric analysis indicated GPR18 deficiency more strongly affected the CD8?? cells in the intraepithelial compared with the adjacent lamina propria compartment. These findings establish a requirement for GPR18 in CD8?? and CD8?? IELs, and we suggest the receptor has a role in augmenting the accumulation of CD8 T cells in the intraepithelial versus lamina propria compartment.

SUBMITTER: Wang X 

PROVIDER: S-EPMC4235638 | biostudies-literature | 2014 Nov

REPOSITORIES: biostudies-literature