FIG. 3.

Antigen-specific IFN-γ-producing lymphocytes isolated from the colon of female and male BALB/c mice following prime-boost immunization. Female and male mice were primed with either peptide (50 μg) with cholera toxin i.n. or MVA (10⁷ PFU) i.d. All animals were boosted with MVA (10⁷ PFU) i.d. Twenty days after MVA boosting, colon lymphocytes were isolated and assayed for the frequency of P18-specific IFN-γ-producing cells by ELISpot. Due to low yields of cells from individual mice, cells isolated from four mice were pooled. Each bar represents the mean ± standard error of six pooled sets of colon tissue (specimens from 24 mice). Lymphocytes isolated from the colons of females primed with peptide and boosted with rMVA had a significantly higher frequency of IFN-γ SFCs than did lymphocytes isolated from the colons of males primed and boosted via the same regimen (P = 0.05 by ANOVA). (Although ANOVA revealed no significance between females and males receiving rMVA-rMVA, Student's t test showed P values of <0.05).