KikGR as a photoconvertible Green-to-Red fluorescent protein has been used to label and track cell migration in different disease models, such as spondylarthritis 68, skin infection 69, 70, tumor 71, etc. In this study, CX3CR1-KikGR transgenic mice were generated and used to specifically track the migration of splenic CX3CR1+ cells from the spleen to the fibrotic liver in vivo (Figure 6A-L and S18C-G). This evidence concerns the gene CX3CR1 and skin infection.