BALB/c mice (7 per group) were immunized i.p. with 2 × 108 CFU of heat- inactivated intact M1883 or purified MCPS in saline, and boosted i.p. with the same dose on day 21. Serum titers of MCPS-specific IgM, IgG, and IgG subclasses (IgG3, IgG1, IgG2b and IgG2a) were determined. Significance (*) p≤0.05 between MenC and MCPS.