Human decay-accelerating factor expressed on rat hearts inhibits leukocyte adhesion.

In xenotransplantation the use of donors transgenic for recipient-type complement regulatory protein decay-accelerating factor (DAF/CD55) or membrane co-factor protein (MCP/CD46) protects grafts against hyperacute rejection (HAR), which is primarily mediated by xenoreactive natural antibodies and complement. In the Langendorff model, we previously demonstrated that rat hearts transgenic for human CD55 (hCD55), perfused with human serum, were protected against HAR. However, ex vivo, these hearts were found to be destroyed by a process occurring after the period of HAR.