MVATG18598 immunization triggers Mtb antigen-specific cells producing IFNγ and induces cells with antigen-specific cytolytic activity.

<p>IFNγ ELISpot responses specific to Mtb antigens following injection of MVATG18598 in <b>(A)</b> BALB/c and <b>(B)</b> C57BL/6 mice. Mice were immunized once with MVATGN33.1 (grey) or MVATG18598 (orange). Results are shown as the number of IFNγ-producing cells per 10⁶ splenocytes (spots/10⁶ cells) following stimulation or not (Medium) with either an irrelevant peptide (Irrelevant) or individual pools of peptides (P) of Mtb antigens expressed by MVATG18598. Each symbol represents individual mice and black lines represent median values of each group (5 or 7 mice/group). The dotted line represents the cut-off value, above which a response was considered as positive (91 and 102 spots/10⁶ cells in (A) and (B), respectively). For each mouse strain, results are representative of independent experiments. <b>(C)</b> CTL killing response to the antigen peptide-pulsed targets in mice immunized with MVATG18598. CB6F1 mice were immunized with either MVATGN33.1 or MVATG18598. Results are expressed as mean ± S.D. of the percentage (%) of specific killing of target cells present in MVATG18598-vaccinated mice minus to those in the MVATGN33.1-vaccinated mice. For each antigen peptide pool (P), statistically significant lysis is indicated by * using a permutation resampling test. <i>p</i> value<0.05.