Fig. 4

Ad5 neutralizing Abs limit GUCY2C responses in humans. a-e) patient serum samples collected prior to vaccination (day 0) were analyzed for Ad5 neutralizing antibodies (NAbs) employing an in vitro Ad5-GFP reporter virus inhibition assay (a). The Ad5 NAb titer was calculated as the dilution of serum that produced 50% inhibition of GFP reporter expression. b patients were rank-ordered by Ad5 NAb titers and patients with titers < 200 were designated as Ad5 NAb Low, while those with titers > 200 where designated Ab5 NAb High (dotted line indicates a titer of 200). c-e antigen-specific responses to GUCY2C (c), PADRE (d), and Ad5 (e) were compared in Ad5 NAb Low and High patient populations by IFNγ-ELISpot (mixed effect model). # P = 0.052, *** P < 0.001