Effects of Ageing and Gender on Naturally Acquired Antibodies to Pneumococcal Capsular Polysaccharides and Virulence-Associated Proteins

Abstract

Elderly individuals are susceptible to pneumococcal infections. Although factors contributing to the increased susceptibility of the elderly to bacterial infections may be several, compromised immune function, a consequence of normal human ageing, is widely accepted to play a role. We evaluated the effect of ageing on the concentrations of naturally acquired antibodies to pneumococcal capsular polysaccharides (PPS) and protein antigens. The concentrations of immunoglobulin G (IgG) and IgM antibodies to the PPS of serotypes 3, 4, 6B, 9V, 14, and 23F and IgG antibodies to the pneumococcal virulence-associated proteins CbpA, LytC, PhtD and its C-terminal fragment (PhtD C), NanA, PspA fam1, and PspA fam2 were measured by enzyme immunoassay in the sera of younger (30 to 64 years of age) and elderly (65 to 97 years of age) adults. The concentrations of anti-PPS IgG against serotypes 3 and 6B, of anti-PPS IgM against serotypes 3, 4, 6B, 9V, and 23F, and of anti-protein IgG against all tested antigens were significantly lower in the elderly than in younger adults. A stronger decline in anti-PPS antibody concentrations was seen with age in women compared to men, while anti-protein antibody concentrations were mainly similar between the genders. Age, gender, and the nature of the antigen have substantial and varying effects on the antibody concentrations in the sera of adults.

Plasma biomarkers of mouse aging

“…It is possible that increased immunoglobulins indicate an increased inflammatory state at old age. However, in contrast to a general increase in immunoglobulins, specific antibodies raised against pathogens such as Streptococcus pneumoniae are actually decreased in older people compared to the younger generation (Simell et al 2008), indicating a weakened immune system at old age. Also, the immune system has been shown to be affected by aging in mice (Richard et al 2005).…”

Persistent Sex Disparities in Invasive Pneumococcal Diseases in the Conjugate Vaccine Era

“…Estrogen receptors are found on a variety of immune cells, including T cells, B cells, dendritic cells, and macrophages [27]. Some studies suggest that females tend to resemble males immunologically as they age [28], which may explain why sex disparities were less pronounced than in younger adults. In addition, sex-related behaviors, such as smoking and exposure to young and school-aged children who are likely to be colonized with pneumococcus, are probably important drivers of IPD risk, especially among adults, but these are difficult to measure and account for.…”

The Capsular Serotype ofStreptococcus pneumoniaeIs More Important than the Genetic Background for Resistance to Complement

“…None of the subjects had been immunized with a pneumococcal vaccine. The concentrations of existing IgG to the corresponding capsular and protein antigens PspA (family 1 and 2), PspC (CbpA), and PhtD were measured by using enzyme immunoassay (EIA) as previously described (45). Each strain was also analyzed once with an agammaglobulinemic human serum (AGS) with nondetectable antibody concentrations to the relevant capsular antigens.…”