Most notably, no specific IgA was detected in the respiratory mucosa of all groups of mice, which contradicts the findings of Ding et al. [36] and Zhuo et al. [37] in their research on influenza A and SARS-CoV-2 viruses, which may be attributed to the antigen characteristics and tissue tropism of the PEDV-S protein [16]. This evidence concerns the gene CD79A and influenza.