FIG. 4.

Passive immunization with antibodies to CP5 and ClfA reduced the intramammary bacterial load 96 h after intramammary challenge. Each bar indicates the mean log₁₀ CFU S. aureus/gland, and the error bars indicate the standard errors of the means (six to eight mice/group). The dotted line indicates the limit of detection by culture (0.7 log CFU/gland). *, significant difference in the number of CFU at 96 h after challenge between mice inoculated with immune serum and the corresponding controls. The levels of significance were as follows: for mice passively immunized with ClfA MAbs versus the control, P < 0.01; for mice passively immunized with CP5 antiserum versus the control, P < 0.01; and for mice passively immunized with ClfA MAbs plus CP5 antiserum versus either control group, P < 0.001.