Intradermal Administration of the Type II Heat-Labile Enterotoxins LT-IIb and LT-IIc of Enterotoxigenic Escherichia coli Enhances Humoral and CD8+ T Cell Immunity to a Co-Administered Antigen
Figure 6
LT-IIb exhibits superior clearance of rLM-OVA and CD8+ T cell recall.
Mice immunized with OVA +/− HLT adjuvants were challenged with 5×106 CFU of recombinant OVA-expressing Listeria monocytogenes (rLM-OVA) 30 days post-vaccination. (A) CFU enumerated from homogenized spleens 3 days post rLM-OVA challenge of mice immunized with OVA and adjuvanted with 1.0 µg of HLT and (B) OVA-specific CD8+ T cell secondary recall 3 days post challenge. Cells gated on live OVA dextramer+TCRβ+CD8+ cells. (C) Splenic CFU and (D) OVA-specific CD8+ T cell recall as before in mice immunized OVA and 0.1 µg of HLT adjuvant. Data shown (n = 8) as a representative of two independent experiments. Statistical analysis: One-way ANOVA with Bonferroni post-test compared to OVA alone unless otherwise noted. *P≤0.05; **P≤0.01; ***P≤0.001. Results shown as the geometric (A, C) or arithmetic (B, D) mean with error bars denoting SEM.