Porcine endogenus retrovirus transmission from pig cell line to mouse tissues but not human cells in nude mice.

The continuous shortage of human donor organs for transplantation has led to new interest in the application of pig organs. However, reports of pig endogenous retroviruses (PERV), which are able to infect human cells in vitro, have raised concerns about the transmission of PERV to the recipients or even to other community members. In this study, PK15 and human 7721 cell lines were implanted into each flank of nude mice and tumors appeared several weeks postimplantation. PERV infection was detected by PCR, using cytochrome oxidase B sequences as the specific marker for pig DNA. The results showed that PERV gag sequence were positive in mice livers, kidneys, hearts, and lungs, but no cytochrome oxidase B sequences detected, which indicates the absence of pig-mouse microchimerism. The results also showed that PERV did not infect human 7721 tumors in mice. This study confirmed the presence of PERV transmission from pig-to-mouse tissue and strengthened the concern of the risk of transmitting PERV through pig cells xenotransplantation.