CUBN and influenza: Overall, the IgM antibody responses to the S1 (RBD) and stable S trimer proteins were low in all mice at the 25 dpi experimental end-point, most likely due to immunoglobulin switch class, as we have recently described in DRAGA mice infected with influenza.27 Though only two out of eight mice were able to recover body weight by 25 dpi, statistical analyses indicated significant correlations between body weights and human IgG Abs to S1(RBD) (Spearman’s rs = (+).9047, P = .002) and with total Igs to N protein (rs = (+).