FIG 4.

Opsonic activity of serum antibodies generated by immunization with CP5-CRM or CP8-CRM against S. aureus strains. The test mixture contained diluted sera, S. aureus, guinea pig serum as a complement source (concentration, 1%), and differentiated HL60 cells. (A and B) Pooled mouse serum (A) or rabbit serum (B) was tested at a 1:40 dilution. Controls lacking antibody, HL60 cells, and complement were included in each assay, as shown in panel A. (C and D) Serially diluted rabbit serum was analyzed against S. aureus serotype 5 strains Newman (C) and USA100 (D). The results are expressed as percent change in the number of CFU/ml at 2 h compared to the number of CFU/ml at time zero. The data shown are means (± standard errors) of two or more experiments. *, P < 0.05; **, P < 0.01.