Fig 2. In vivo cellular immunogenicity of MVA deletion mutants, lacking fifteen genes, with TIP antigen.

Two groups of female BALB/c mice (n = 10) were immunized (i.m.) with MVAwt with TIP model antigen (MVA-TIP), or MVA deletion mutant (lacking 15 genes) ∆15-MVA-TIP at the dose of 1x10⁶ pfu/ml. Seven days post immunization (top), ex vivo ELISpot was performed to determine the percentage of IFN-γ-secreting CD8⁺ splenocytes in response to in vitro re-stimulation with pb9 peptide (A), or with MVA vector-specific peptides (B and C) (all three peptides are CD8⁺ T cell specific). 28 days (middle), or 84 days (bottom) post immunization, five mice were sacrificed and spleens collected for intracellular cytokine staining and flow cytometry to determine the percentage of IFN-γ-secreting CD8⁺ T splenocytes in response to in vitro re-stimulation with pb9 peptide (A), or with MVA vector-specific peptides (B and C). These values are presented after subtracting the values of unstimulated cells for every mouse (sample). The mean of each group with the SEM error bars are shown. Data is representative of two independent experiments. * P = 0.0331 using Mann Whitney test.