Aging and the immune response to the Haemophilus influenzae type b capsular polysaccharide: retention of the dominant idiotype and antibody function in the elderly

Abstract

Anti-Haemophilus influenzae b polysaccharide (Hib PS) antibodies elicited in elderly subjects following conjugate vaccination expressed a light-chain variable-region (VL)-associated idiotype and had functional activities similar to those previously observed in children and younger adults. These findings indicate that advanced age is not accompanied by shifts in the major VL component of the Hib PS-specific repertoire or by diminution of the protective function of antibodies.

FIG. 1

Expression of HibId-1 by anti-Hib PS antibodies in sera from elderly individuals vaccinated with either Hib PS-OMP or HbOC vaccines. Each filled circle represents the value for an individual serum. A subject was considered positive for HibId-1 if ≥20% (dotted line) of the serum antibody expressed HibId-1. Nine of 15 (60%) and 12 of 15 (80%) of subjects were positive for HibId-1 in the Hib PS-OMP and HbOC groups, respectively. The dashed lines indicate the mean HibId-1 percentage in elderly subjects considered positive for HibId-1. The hatched boxes labelled A, B, C, and D indicate previously determined mean percentages of HibId-1: A, 6-month-old infants vaccinated three times with Hib PS-OMP (4); B, 2-month-old infants vaccinated once with Hib PS-OMP (7); C, adults (mean age = 32 years) vaccinated once with Hib PS-OMP (7); and D, 6-month-old infants vaccinated three times with HbOC (4).