Dietary Neu5Gc does not elicit anti-Neu5Gc antibodies. (A and B) WT (open bars, n = 8) and Cmah^−/− (filled bars, n = 8) were fed ∼1 mg/kg/day Neu5Gc (from normal chow) after weaning (4–6 wk total), immunized with human RBC ghosts (WT, n = 4; Cmah^−/−, n = 4), or immunized with chimpanzee RBC ghosts (WT, n = 4; Cmah^−/−, n = 4). Sera were analyzed by ELISA for IgM (A; note the broken y axis) and IgG (B) antibodies against Neu5Gcα-PAA and shown as mean absorbance values at OD₄₀₅ ± SEM. Statistical analysis was performed using an unpaired two-tailed Student’s t test. n.s, not significant, *, P < 0.05; **, P < 0.01. Data are representative of greater than three independent experiments.