TYK2 and infection: The virus titres in the pancreas of Tyk2 KO mice showed longer persistence and was at a significantly higher level from 1 to 5 days after infection in comparison with Tyk2 WT mice, with ∼60-fold differences between the two groups on day 5 (Fig. 2c), suggesting that increased proliferation of the EMC-D virus in the pancreas of Tyk2 KO mice might lead to the extensive damage of the pancreatic β-cells.