In the present study, thermal cautery, which led to an increase in MHC class II
+ LCs in the central areas of the corneal epithelium, was associated with an overexpression of the chemokines RANTES, MIP-1α, MIP-1β, eotaxin, and MIP-2, but not IP-10, MCP-1, and lymphotactin. In addition, CCR1 (e.g., RANTES, MIP-1α, MCP-3), CCR2 (MCP-1, -2, and -3), and CCR5 (e.g., RANTES, MIP-1α, MIP-1β)
38 39 receptor genes, but not CCR3 (eotaxin) or -4 (MDC) receptor genes are overexpressed at the same time points after cautery. Because the initial data primarily implicated the CCR1, -2, and -5 to be associated with the increase of MHC class II
+ LCs in the central cornea, we further assessed the functional relevance of these CC receptors by studying the recruitment of MHC class II
+ LCs in CCR1-, CCR2/MIP-1α-, MIP-1α-, and CCR5-KO mice compared with respective wild-type mice. Our results revealed that MHC class II
+ LCs in the corneal epithelium are significantly, but not entirely, suppressed in CCR5
−/− mice compared with wild-type control animals, whereas no significant differences in CCR1-, CCR2/MIP-1α-, and MIP-1α-KO are appreciated compared with controls. The finding that blockade of the CCR5 ligands RANTES and MIP-1β decreased the number of MHC class II
+ LCs also strongly supports the functional relevance of CCR5 in the recruitment of MHC class II
+ LCs.