Porcine endogenous retroviruses inhibit human immune cell function: Risk for xenotransplantation?

Transgenic pigs are currently the most favored potential source of organs f or xenotransplantation. Like all mammalian species they all harbor endogeno us retroviruses in their genome. These porcine endogenous retroviruses (PER Vs) are produced from several primary cells and cell lines and are able to infect human cells. Here we demonstrate that different pig strains and diff erent animals of one strain differ in their ability to produce PERVs from n ormal blood cells. We report that purified PERV particles show a protein pa ttern typical for type C retroviruses and are antigenically related to mamm alian leukemia viruses. Like most retroviruses, purified PERVs and peptides derived from the highly conserved immunosuppressive domain of their transm embrane envelope protein inhibit human immune cell functions. This indicate s that high titer replication of PERVs in the transplant recipient could th erefore lead to an immunodeficiency disease, (C) 2000 Academic Press.