TABLE 1.

IgA, IgG, and IgM antibodies against serotypes 14, 18C, and 23F among young and elderly adults

ParameterValuea
Serotype 23FSerotype 18CSerotype 14
YoungOldPYoungOldPYoungOldP
Concn of antibodyb
    IgG3.17 (2.34-4.30)2.71 (1.93-3.81)0.474.67 (3.45-6.33)4.92 (3.50-6.91)0.811.85 (8.74-16.06)7.00 (4.98-9.84)0.14
    IgA0.54 (0.40-0.73)0.27 (0.19-0.38)<0.01NDNDNDND<0.01
    IgM0.2 (0.15-0.27)0.09 (0.06-0.13)<0.010.46 (0.34-0.62)0.19 (0.13-0.27)<0.011.04 (0.77-1.41)0.35 (0.24-0.5)<0.01
Opsonic indexc752 (554-1,019)186 (132-260)<0.011,149 (848-1,558)698 (497-981)0.184,939 (3,643-6,695)1,102 (784-1,548)<0.01
Antibody potencyd250.73 (184.95-339.89)80.23 (57.09-112.73)<0.01243.35 (179.01-330.82)157.22 (111.89-220.93)0.16381.29 (280.48-518.35)160.24 (114.03-225.17)<0.01
  • a Values in parentheses are 95% confidence intervals. ND, not determined.

  • b Geometric mean concentration, in micrograms per milliliter.

  • c Geometric mean opsonophagocytic index.

  • d Geometric mean antibody potency (OI/[IgG]).