Characterization of porcine endogenous retrovirus particles released by the CRISPR/Cas9 inactivated cell line PK15 clone 15
Level 5 - mechanism / opinion, no new human data
In vitro bench study of gene-edited cell lines
OpenAlex W2982561807 · doi:10.1111/xen.12563
What was done
Researchers evaluated the virological safety and reinfection susceptibility of PK15 clone 15, a porcine kidney cell line in which porcine endogenous retrovirus (PERV) reverse transcriptase (RT) was inactivated via CRISPR/Cas9. They measured basal expression of PERV pol, the porcine PERV-A receptor (POPAR), and RT activity. PK15 clone 15 cells were challenged with infectious PERV to assess viral expression and RT activity post-inoculation. Released viral particles were imaged with electron microscopy, and cell supernatants were applied to susceptible swine testis-IOWA (ST-IOWA) cells to measure infectivity.
What was found
The abstract reports no numerical values. PK15 clone 15 cells continued to express viral proteins and assemble virions, but electron microscopy showed irregular morphology diverging from mature wild-type particles. Supernatants from PK15 clone 15 failed to infect ST-IOWA cells. Expression of the PERV-A receptor POPAR was identical between wild-type PK15 and PK15 clone 15 cells. The CRISPR-modified cells retained cellular resistance to superinfection despite possessing normal receptor levels.
Why it matters
These findings suggest that CRISPR/Cas9 inactivation of PERV RT produces non-infectious, defective virions while maintaining resistance to PERV superinfection, supporting the safety profile of CRISPR-edited porcine cells for xenotransplantation research.
Limits
This was an in vitro study performed on a single porcine cell clone, which may not capture in vivo physiology or long-term pathogen dynamics in whole animals or human xenograft recipients. The abstract does not provide quantitative data, confidence intervals, or sample replication counts, and testing was primarily focused on PERV-A mechanisms.
Cited by
- supports George Church's group engineered pig germlines with 42 to 62 simultaneous genome edits targeting porcine endogenous retroviruses and immunological genes for xenotransplantation.