In vivo immunogenicity showed that the delivery of 2′3′-cGAMP after viral infection (by means of co-expressing it as a transgene) enhanced the CD8+ T cell immunogenicity against Pb9 and eGFP200-208 (Mann–Whitney test: **p = 0.0070 and *p = 0.0467, respectively), but not the CD4+ T cell immunogenicity against P15 (p > 0.05) (Fig. 4a–c). Here, CD4 is linked to viral infectious disease.