Fig. 5
In vivo immune responses of oral UC peptides and complement activity of immunized serum. (a) BALB/c mice (n = 5) were orally administered 3 doses of 200 µg UC-100 14 days apart. (b–d) The serum of UC-100 mice was collected pre-(Day-1) and posttreatment (Day 41) and tested in duplicate and represented as the mean for the levels of (b) total IgG; (c) specific IgG against UC-100 peptide; (d) specific IgG against SARS-CoV-2 spike trimer protein; (e) The antibody-mediated complement activity was tested in duplicate and represented as the mean for pre- and postserum of mice vaccinated with UC-100. The complement activity was expressed as the IC50 of cytotoxicity. (f,g) The serum of UC-100 mice was collected pre-(Day-1) and posttreatment (Day 41) and tested in duplicate and represented as the mean for the levels of (f) total IgA and (g) specific IgA against UC-100 peptide. Significant differences are indicated by asterisks (unpaired one-tailed Student’s t test; *p < 0.05, **p < 0.01, ***p < 0.001).
