INFECTION OF HUMAN-CELLS BY AN ENDOGENOUS RETROVIRUS OF PIGS

The possible use of pig organs and tissues as xenografts in humans is actively being considered in biomedical research. We therefore examine d whether pig endogenous retrovirus (PERV) genomes can be infectiously transmitted to human cells in culture. Two pig kidney cell lines spon taneously produce C-type retrovirus particles. Cell-free retrovirus pr oduced by the PK-15 kidney cell line (PERV-PK) infected pig, mink and human kidney 293 cell lines and co-cultivation of X-irradiated PK-15 c ells with human cells resulted in a broader range of human cell infect ion, including human diploid fibroblasts and B- and T-cell lines. Kidn ey, heart and spleen tissue obtained from domestic pigs contained mult iple copies of integrated PERV genomes and expressed viral RNA. Upon p assage in human cells PERV-PK could rescue a Moloney retroviral vector and acquired resistance to lysis by human complement.