Gamma Delta T Cell Dependent Inflammation and Wound Healing in the Mouse Corneal Epithelium

Abstract

We found that γδ T cells migrate into murine corneal epithelium in response to epithelial wounding, and wound healing and inflammation are significantly reduced in TCRδ −/− mice (Am. J. Pathol 171:838–845, 2007). The current work is to define mechanisms for migration of γδ T cells into corneal epithelium. Limbal and paralimbal corneal epithelium was collected at 0 and 3 hrs after central abrasion in female C57BL/6 mice for qrtPCR, and immunocytology. Results: ICAM‐1 mRNA was increased 26 fold at 3 hrs. Anti‐ICAM‐1 staining was negative at 0 hr, but strongly positive over the limbal and paralimbal epithelium at 3 hrs. γ/δ T cells increased at 3 hrs after injury, but ICAM‐1−/− mice failed to show an increase. Of 11 chemokine receptors probed, only CCR3 and CCR5 were significantly increased in wildtype mice at 3 hrs. mRNA for chemokines recognized by these receptors was significantly increased: CCL3 (MIP‐1α), CCL4 (MIP‐1β), CCL5 (RANTES) and CCL7 (MCP‐3). Further, CXCL10 (IP‐10) mRNA was also significantly increased. CXCL10 is known to attract some γδ T cells, but its receptor (CXCR3) was not evident here. Conclusion: The migration of γδ T cells into murine corneal epithelium in response to epithelial abrasion appears to depend on ICAM‐1 expression, and since CCR5 is reported on some γδ T cells, our observations suggest a mechanism for attraction into corneal epithelium.Source of research support: General Clinical Research Centers