Fig 2: cGAMP-STING?TM tetramer promotes robust antigen-specific T cell responses.(A) Groups of C57BL/6 mice (n = 7) were immunized with 50 µg of OVA alone or OVA mixed with 1 µg of cGAMP or 40 µg of STING?TM (or 40 µg of S365A STING?TM) on days 0 and 7. On day 14, PBMCs were collected and CD8+ T cells were analyzed by CD8 OVA epitope SIINFEKL tetramer staining (B) or stimulated ex vivo with CD8 OVA epitope SIINFEKL and analyzed by intracellular cytokine staining of IFN-? (C) and TNF-a (D). (E) Groups of C57BL/6 mice (n = 5) were immunized with 50 µg of OVA alone or OVA mixed with 1 µg of cGAMP or 40 µg of STING?TM (or 40 µg of S365A STING?TM) on days 0 and 14. On day 21, PBMCs and lymphocytes in dLN and splenocytes were collected and CD8+ T cells were analyzed by CD8 OVA epitope SIINFEKL tetramer staining. Among CD8+ SIINFEKL tetramer+ T cells, effector memory precursors TEMP were gated by CD27+ CD62L- and KLRG1- [(F) in dLN lymphocytes, (H) in PBMCs, and (I) in splenocytes], and central memory precursors TCMP were gated by CD27+ CD62L+ and KLRG1- [(G) in dLN lymphocytes and (J) in splenocytes, TCMP was generally not found in PBMCs]. Values are reported as means ± SEM. ***P < 0.001, **P < 0.01, and *P < 0.05, as analyzed by one-way ANOVA.