In Salmonella-infected mice, serum IgG3 and IgG2c concentrations were significantly increased, by an average of threefold to fivefold over those in uninfected controls, in both mouse strains (Figures S4A,B in Supplementary Material), while no significant changes in serum IgG1 concentrations were observed upon infection with Salmonella in both mouse strains. Here, IGHG3 is linked to infection.