Transfer of porcine endogenous retrovirus across hollow fiber membranes - Significance to a bioartificial liver

Background. A porcine endogenous retrovirus (PERV*) capable of infecting hu man cells has been identified. This study was designed to determine whether hollow fiber membranes, such as those used in a bioartificial liver, block the transfer of PERV. Methods. Three hollow fiber cartridges (HFCs) were studied in duplicate: ce llulose fibers with 70 kD nominal molecular weight cut-off (MWCO), polysulf one fibers with 400 kD MWCO, and mixed cellulose fibers with 200 nm porosit y. PK15 cells (porcine kidney cell line), known to produce PERV, were grown in the intraluminal compartment of HFCs fiber cartridges. Samples of mediu m were collected from both intraluminal and extraluminal compartments of th e HFCs fiber cartridge during 14 days of culture. Samples were screened for PERV using reverse transcription polymerase chain reaction. All positive s amples were tested for PERV infectivity in human 293 cells. Results. PERV was detected in all samples from the intraluminal space and a ll intraluminal samples seemed to infect 293 cells. All extraluminal sample s from the fibers of 200 nm porosity tested positive for PERV, Detection of PERV in the extraluminal space was delayed by fibers of 400 MD MWCO and 70 kD MWCO until at least day 3 and day 7, respectively, after inoculation of PK15 cells. Positive extraluminal samples from fibers of 400 kD MWCO and 7 0 kD MWCO did not infect 293 cells, Conclusion. Pore size, membrane composition, and duration of exposure influ enced the transfer of PERV across HFCs, Some HFCs decrease the risk of vira l exposure to patients during bioartificial liver therapy.