Figure 4.

HIV-specific T cell responses to poxvirus vaccine prime and boost vaccination regimens. Groups of mice were primed with rLSDV-grttn or rMVA-grttn then boosted on day 28 with either rMVA-grttn or rLSDV-grttn as indicated on the y-axis. Mice in all the groups were killed on day 40, 12 days after the final immunization. Splenocytes pooled from 5 mice per group were used in the immunological assays. (a) IFN-γ ELISPOT assay with Gag and RT CD8 and CD4 peptides. Bars are the mean ± the SD of spot forming unit (sfu) from triplicate reactions for 10⁶ splenocytes after subtraction of background spots in the absence of peptide. (b), splenocytes were also cultured with the individual HIV CD8+ and CD4+ T cell peptides for 48 h and culture supernatants were collected and IFN-γ (pg cytokine/10⁶ splenocytes) content quantified. The sum of IFN-γ produced during stimulation with the individual CD8+ and CD4+ T cell peptides was calculated and is presented as the cumulative total IFN-γ produced by HIV-specific CD8+ T cells or CD4+ T cells, values are indicated on the bars; and (c) IL-2 ELISPOT assay with pooled splenocytes and peptides as used in the IFN-γ ELISPOT assay; (d) pooled splenocytes were also labelled with APC-conjugated H-2D^k pentameric complexes folded with the Gag AMQMLKDTI peptide or the RT peptide VYYDPSKDLIA and PerCP-conjugated anti-CD8α on day 28. Gag and RT -specific MHC class I pentameric complex binding is expressed as a percentage of gated CD8+ T cells, percentages are indicated on the bars. *: p < 0.01; **: p < 0.05. All data are from a representative experiment.