Means (± standard deviation) of relative expression of cell-mediated immune-response-related genes CD8+ mRNA expression (A,B); Granzyme A mRNA expression (C,D) and Perforin-1 mRNA expression (E,F) in trachea (A,C,E) and kidney (B,D,F) samples, observed at 1, 5, and 11 dpi of negative control (NC) group, nonvaccinated and challenged (NV) group, vaccinated with AvCoV-CS and challenged (Nano) group, vaccinated with H120 strain and AvCoV-CS and challenged (L+Nano) group, vaccinated with AvCoV-O and challenged (Oil) group, and vaccinated with H120 strain and AvCoV-O and challenged (L+Oil) group. Significantly (p ≤ 0.05) different values are shown as different letters.