Abstract
2'3'-cyclic GMP-AMP (2'3'-cGAMP) and 3'2'-cGAMP activate STING-dependent antiviral immunity in Drosophila melanogaster but fail to control infection by C virus in some fly species. In this issue of Immunity, Cai et al. reveal that Drosophila produces multiple cyclic di-nucleotides (CDNs) in response to viral infection. One of these CDNs-2'3'-c-di-GMP-is a very potent STING activator capable of promoting antiviral immunity in otherwise susceptible flies.
