FIG. 6.

Bactericidal activity of normal bovine serum against H. somnus strain 738-lob2A1::Km, which is deficient in the terminal Galβ-(1-3)-GlcNAc disaccharide on its LOS. Log-phase bacteria were incubated for 3 h with (solid line) or without (dashed line) CMP-NeuAc and then incubated with various concentrations of normal calf serum for 1 h, as described in Materials and Methods. Bactericidal activity was determined by viable plate count at time zero and 60 min after incubation. Error bars indicate standard deviations.