Determination of the optimal dosage of MVA-GagM to boost a BCG-GagM prime.

(A) Mice were primed on day 0 with 2 x 107 cfu BCG-GagM (Group 1–3) or BCGE (Group 4–6) and boosted on day 70 with 102 (Group 1 and 4), 104 (Group 2 and 5), or 106 (Group 3 and 6) pfu MVA-GagM. (B) Cumulative IFN-γ ELISPOT CD8+ and CD4+ responses of vaccinated mice to HIV-1 Gag peptides. The ELISPOT assay was carried out using three Gag-specific peptides for stimulation of pooled splenocytes that were isolated 12 days post the MVA-GagM boost. Bars represent the magnitude of net responses to individual peptides, expressed as sfu/106 splenocytes after subtracting the background. (C) and (D) Total frequency of T cells producing IFN-γ, IL-2, and/or TNF-α, after subtracting the background, in response to HIV-1 Gag peptide stimulation following a rBCG prime and an MVA-GagM boost at different doses. Cells were positive for cytokine production if the proportion was ≥0.05% after subtracting the background. These results are from a single experiment using pooled splenocytes.