CGAS and infection: Moreover, although B2 (encoded by the B2R gene) was identified as a cGAMP nuclease19, VACV∆B2R infection did not induce IFN-β secretion from WT BMDCs (Fig. 1d), suggesting the presence of other viral inhibitors of the cGAS/STING/IFNB pathway in VACV∆B2R.