An invertebrate STING from shrimp activates an innate immune defense against bacterial infection

It has been proposed that invertebrate stimulators of interferon genes (STINGs) do not take part in the innate immune response to infection. Herein, we identified a new STING homolog from pacific white shrimp Litopenaeus vannamei (LvSTING). Some amino acids crucial for recognizing cyclic dinucleotides in mammals are highly conserved in LvSTING. Moreover, LvSTING expression can be robustly induced by challenge with the Gram-negative bacteria Vibrio parahaemolyticus. Silencing of LvSTING contributes to decreased expression of the antimicrobial peptide PEN4 and renders shrimp more susceptible to V. parahaemolyticus infection, while coinjection with the recombinant LvSTING protein can rescue PEN4 expression in vivo and confer shrimp with more resistance to infection. Taken together, these results suggest that LvSTING is involved in the innate immune response to bacterial infection.