Porcine skin is frequently used as a substitute of human skin to cover large wounds in clinic practice of wound care.In our previous work,we found that transgenic expression of human cytox-icT-lymphocyte associated antigen4-immunoglobulin (hCTLA4Ig) in murine skin graft remarkably pro-longed its survival in xenogeneic wounds without extensive immunosuppression in recipients,suggest-ing that transgenic hCTLA4Ig expression in skin graft may be an effective and safe method to prolong xenogeneic skin graft survival.In this work,using a transgene construct containing hCTLA4Ig coding sequence under the drive of human Keratine 14 (k14) promoter,hCTLA4Ig transgenic pigs were generated by somatic nuclear transfer.