HAdV-5 vaccine vectors elicit higher CD8+ T cell and antibody responses and deliver superior transgene expression in vivo compared to ChAdOx1 vectors.
BALB/c mice (5/group) were vaccinated intramuscularly with 108 infectious units (ifu) HAdV-5 or ChAdOx1 expressing Photinus luciferase. Two weeks post vaccination, (A) splenic CD8+ T cell responses against dominant Luc160-168 epitope GFQSMYTFV were measured by IFN-γ ELISpot and (B) anti-luciferase IgG titers were assessed in serum by endpoint ELISA. Statistical analyses performed by student T-test. (C) Prior to termination of the experiment, luciferase expression in vivo was measured in the same animals by bioluminescence imaging on day, 1, 3, 7 and 14, post vaccination. Graph shows mean total flux units per second (p/s) ± range. (D) Overlay image indicating the location of the bioluminescence signal 24 h post vaccination in both HAdV-5 and ChAdOx1 vaccinated groups. Intensity of signal indicated, where red is most intense (108 p/s) and violet is least intense (107 p/s).