Kinetics of antigen expression control lentivector-induced secondary CD8⁺ T-cell response.

<p>(<b>A</b>) B6 mice were primed, or primed and boosted intradermally with 5×10⁶ TU of Lv-OVA/Luc, and luciferase expression was determined <i>in vivo</i> using whole body imagining. The mean relative light unit (RLU) values expressed by a group of 4 mice ± SE are presented. (<b>B</b>) Immunization site of Lv-OVA (5×10⁶ TU) homologously boosted mice was removed on days 2, 4 or 6 following immunization, and the magnitude of OVA-specific CD8⁺ T cells was analyzed. Data are showed as the mean percentage ± SE of CD8⁺ tetramer⁺ T cells. n = 3 mice per group for each time point. (<b>C</b>) Mice were primed with Lv-OVA and 7 weeks later were boosted with Lv-OVA (Lv-Lv) or Ad-OVA (Lv-Ad). In parallel, other groups of naïve mice were primed with Lv-OVA (Lv prime) or Ad-OVA (Ad prime) using the same viral vector employed for boosting to allow adequate comparison. Two weeks after immunization tetramer analysis was performed on blood samples obtained from the mice (n = 4 to 5 mice for each group). The graph represents the fold increase in the magnitude of OVA-specific CD8⁺ T cells, Lv-Lv versus Lv prime, and Lv-Ad versus Ad prime. Results described in this figure are representative of two independent experiments. *, <i>P</i><0.01, prime versus boost response at the indicated time points. #, <i>P</i><0.05, compared to control uncut boosted group.