Kidneys from HDAF transgenic pigs are physiologically compatible with primates

Decay-accelerating factor (CD55): a versatile acting molecule in human malignancies

The decay-accelerating factor (DAF, CD55) physiologically serves as an inhibitor of the complement system. Moreover, DAF is broadly expressed in malignant tumors. Here, DAF seems to dispose of several different functions reaching far beyond its immunological role, e.g., promotion of tumorigenesis, decrease of complement mediated tumor cell lysis, autocrine loops for cell rescue and evasion of apoptosis, neoangiogenesis, invasiveness, cell motility, and metastasis via oncogenic tyrosine kinase pathway activation, and specific seven-span transmembrane receptors (CD97) binding. Furthermore, DAF has already been included in diagnostic or therapeutic studies. Thereby, studies applying monoclonal anti-DAF antibodies and anti-DAF vaccination for a targeted therapy have been enrolled recently.

Genetic therapies and xenotransplantation

The number of patients in need of an organ transplant is increasing, while the number of satisfactory sources of organs has declined in many countries [101]. The resulting shortage of human organs has spurred an urgent effort to investigate alternative therapies, including the use of animal organs, tissues and cells (i.e., xenotransplantation). Advances in genetic engineering have provided essential tools for the development of practical solutions to human disease. The area of xenotransplantation is no exception. In fact, the use of genetic therapies is especially attractive in the transplant setting as it offers an opportunity to manipulate the donor tissue rather than the recipient. This review will describe the obstacles in the clinical application of xenotransplantation and how genetic engineering might be used to address them.

Physiologic and immunologic hurdles to xenotransplantation

The major problem in the field of renal transplantation is currently the shortage of available kidneys. However, the use of animals as a source of kidneys, i.e., xenotransplantation, is increasingly being viewed as a potential solution to this problem. One preeminent hurdle to xenotransplantation is the immune response of the recipient against the graft; other hurdles include the physiologic limitations of the transplant, infection, and ethical considerations. This review summarizes what is currently known regarding the obstacles to xenotransplantation and some potential solutions to those problems.