Central role for type I interferons and Tyk2 in lipopolysaccharide-induced endotoxin shock.

Toll-like receptor-4 activation by lipopolysaccharide (LPS) induces the expression of interferon-beta (IFN-beta) in a MyD88-independent manner. Here we report that mice devoid of the JAK protein tyrosine kinase family member, Tyk2, were resistant to shock induced by high doses of LPS. Basal and LPS-induced expression of IFN-beta and IFN-alpha4 mRNA in Tyk2-null macrophages were diminished.