As espP was identified as one of the potential virulence-associated genes that significantly upregulated in vivo (Mao et al., 2020), it indicates that G. parasuis IgA protease was up-regulated during infection and secretion of IgA-specific protease EspPs may serve G. parasuis to evade IgA-mediated mucosal immunity under physiological conditions. The gene discussed is CD79A; the disease is infection.