FIG. 2.

Cellular immune responses stimulated in mice using cdiGMP as a mucosal adjuvant. (A) Proliferative responses stimulated in mice immunized using cdiGMP as an adjuvant. Spleen cells from vaccinated animals were restimulated with different concentrations of β-Gal for 96 h. Cellular proliferation was assessed by the determination of the [³H]thymidine incorporated into the DNA of replicating cells. Results are averages of triplicates, and they are expressed as counts per minute (cpm). The results obtained in cdiGMP-vaccinated animals were statistically significant with respect to those observed in mice receiving β-Gal alone, at a P value of <0.05 (*). Data from one representative experiment out of four independent experiments are shown. (B) Assessment of the effect of coadministration of cdiGMP on CTL responses as measured by the VITAL assay (in vivo CTL) (see Materials and Methods). Lysis of CFSE⁺ Ova peptide-loaded splenocytes was monitored relative to that of unloaded splenocytes in spleens taken from mice that had been immunized three times with 50 μg of Ova alone or coadministered with 5 μg cdiGMP by intranasal application 4 weeks after the last immunization. The percentage of specific lysis for each group of two animals is shown.