Fig 3. Measurement of opsonophagocytic killing of monoclonal antibodies VH4E and VH8 and the mouse anti-lipoteichoic monoclonal antibody against (A) MRSA strain LAC and (B) E. faecalis 12030.

The opsonophagocytic assay was performed using baby rabbit serum as complement source and rabbit sera raised against purified LTA from E. faecalis 12030. VH4E and VH8 show high opsonic killing against both strains in a dose dependent manner and are clearly more efficient than the mouse anti-lipoteichoic monoclonal antibody, which showed modest killing against LAC at very high concentrations (i.e. 1,000x). Opsonophagocytic killing activity was compared to controls from which leukocytes were omitted. Statistical analysis was done by ANOVA with Dunnett post test. * p<0.05, ** p<0.01, *** p<0.001. Error bars represent standard error of the mean.