Generation and Characterization of STING Antibodies

We generated a mouse monoclonal antibody that recognized an epitope within amino acids 322-339 of human STING and within amino acids 321-338 of mouse STING (Fig. S2A-D). A polyclonal antibody against phospho-S365 of mouse STING was generated in rabbits and affinity-purified (Fig. S2E). Polyclonal antibodies against mouse STING, Igα, Igβ, class I MHC heavy chain, and class II MHC α chain were generated in rabbits. An anti-SEL1L polyclonal antibody was also generated in rabbits and affinity-purified. The following antibodies were purchased: XBP1s (Cell Signaling), HRD1 (Abgent), HRD1 (Proteintech), p97 (Fitzgerald), μ (SouthernBiotech), κ (SouthernBiotech), phospho-Syk (Cell Signaling), Syk (Cell Signaling), phospho-Igα (Cell Signaling), TCL1 (Cell Signaling), cleaved caspase 3 (Cell Signaling), cleaved caspase 7 (Cell Signaling), calnexin (Proteintech), and actin (Sigma). LPS and digitonin were purchased from Sigma. Recombinant mouse IFNβ and TNFα were procured from Biolegend. Kifunensine and MG132 were purchased from Cayman. 3’3’-cGAMP was chemically synthesized as described previously.^{28 (link)}