Definition of a production specification for xenotransplantation. A European perspective.

In the absence of regulatory guidance on animal production for xenotransplantation and the need to conform to European, U.K. and international standards of animal health and welfare, Imutran set up a forum of experts in 1994 to assess the risks associated with the possible transmission of diseases from pig to man after transplantation of porcine tissue. This risk assessment set the specification for Qualified Pathogen-Free pig production and the animal testing required to demonstrate that the specification has been achieved. The invasive sampling required for detailed health monitoring of individual source animals is in conflict with the aim of producing healthy, normal animals that are not subject to undue stress, and produces predominantly retrospective data on a donor. Imutran has developed a sampling regime that qualifies age-class cohorts and the whole herd by the routine testing of representative sentinel animals. Imutran set up a pilot production unit in 1995 and this unit has remained populated beyond a 30-month period and has received in excess of 20 cohorts of animals by hysterectomy re-derivation. Rigorous testing of sentinels and noninvasive testing of individuals have demonstrated that this pilot unit has achieved the required specification on a routine basis in a system that has been designed to meet European ethical and animal welfare concerns, within the constraints of the strict U.K. animal research laws and an ISO 9001 quality environment.