Specific immunoglobulin-class antibody responses in the elderly before and after 14-valent pneumococcal vaccine.

Using an enzyme-linked immunosorbent assay for measuring IgG-, IgA-, and IgM-class antibodies to pneumococcal capsular polysaccharides, we studied responses of debilitated patients 71 to 95 years of age (average, 85 years) in nursing homes to 14-valent pneumococcal vaccine. A control group consisting of normal adults 23 to 41 years of age (average, 27 years) was used for comparison. Normal adults at 28 days postvaccination showed rises in IgG-, IgA-, and IgM-class antibodies to nearly all capsular polysaccharides. The IgG- and IgA-class antibody responses of the elderly patients did not differ significantly from those of the normal adults in most instances. IgM-class responses of the elderly subjects were poor and were significantly lower than those of the control group for six of 14 serotypes. Overall, these studies demonstrate that elderly patients, like healthy younger adults, mount a polyclonal antibody response to pneumococcal polysaccharide vaccine.