FACS-based CRISPR knockout screen identifies interferon stimulated genes that control Toxoplasma in pig cells

Acute Toxoplasma infection in pigs can cause severe morbidity and mortality, while chronic Toxoplasma infection suppresses immunity and presents significant risk to human foodborne infection. In virtually all vertebrate hosts, interferons (IFNs), through the induction of hundreds of interferon-stimulated genes (ISGs), control Toxoplasma pathogenesis. Compared to mice and humans, very little is known about the ISGs that control Toxoplasma in pigs.

To address this knowledge gap, we developed the first CRISPR knockout library exclusively targeting over 1000 canonical porcine ISGs (pISG-knockout library) and used it to screen for ISGs that control a type II Toxoplasma strain in Neonatal Swine Kidney (NSK) cells. Known ISGs such as GBP1, STAT1, IRF1 and IFNGR1 were among the top 10 hits from the screen, confirming the potential of the pISG-knockout library to identify ISGs controlling Toxoplasma in pigs. We are currently working on the functional validation and mechanistic characterization of the candidate genes arising from the screen.