Infectious Risk and Protection

Xenotransplantation as an optional strategy can overcome the human transplantable organs and donor shortage and failure of functional organs. The currently outstanding three barriers are existed in clinical xenotransplantation, and they are the immune rejection, the physiological compatibility achievement, and zoonotic microorganism transmission from pigs to human. Among them, recently issued obstacle in xenotransplantation is the problems caused by the inter- and cross-species transmission of pig pathogens, but this is anticipated in improvement as recently CRISPR-Cas9-applied genome-wide inactivation of PERVs has been performed. Xenozoonosis has been recognized as a great interest from the worldwide outbreak of Flu and respiratory syndrome, although exogenous retroviruses are not demonstrated in pigs. Pig-to-human xenotransplantation has been advanced in animals to improve immunological and microbial compatibility. The zoonotic xenotransplantation safety is a risk for infection. Therefore, considering the zoonotic property in xenotransplantation, pig cells and organs should be treated after pig management from conditions of defined pathogen-free (DPF) or specified pathogen free (SPF) state. SPF indicates the completely pathogen-free swine herds from the specified pathogenic bacteria and viruses representatively. SPF piglets are sterilely protected and generated by Caesarean delivery on xenotransplantation request. To examine microbiological safety of pig breeds and to combat unknown risks, many efforts were made. In breeding of pigs, the SPF pig breeding facilities are limited due to short-term pig research history.