Demonstration of specificity of in vivo CP immune responses in mice challenged with <i>S</i>. <i>aureus</i> isolates.

CP5 antibody titers in mice challenged with CP5 S. aureus isolates (MSSA strain Reynolds, two USA300 MRSA isolates PFESA0029 [CDC3] and PFESA0119, PFESA0119 Δcap5HIJK ermC capsule knock-out strains). CD1 mice (7–9 weeks of age, 10 per group) were administered three IP injections of ~ 2x106 CFU/animal in 0.5 mL at 0, 6 and 14 weeks, and bled two weeks after the final inoculation. CP5 antibody responses were measured using a CP5 specific cLIA assay. CP5 antibody responses were detected in mice infected with strain Reynolds, and PFESA0029 and PFESA0119 isolates, while the capsule knockout mutant was not able to induce a CP5 antibody response. GMT fold change over the antibody titer of the capsule knockout mutant was calculated for all tested isolates.