Salivary Functional Antibody Secretion Is Reduced in Older Adults: A Potential Mechanism of Increased Susceptibility to Bacterial Infection in the Elderly

Research output: Contribution to journalArticle

Abstract

Background. Bacterial infections in the elderly are common and associated with high morbidity and mortality, with pneumonia the second commonest cause of death. Reductions in antibodies against specific bacterial antigens in saliva and serum could contribute to infection risk in older adults, although they have yet to be examined in relation to age.

Method. IgG, IgA and IgM antibody levels in paired saliva and serum samples were measured against 12 pneumococcal, 4 meningococcal and haemophilus polysaccharide antigens and diphtheria and tetanus toxoids in healthy younger (n = 28, 21–34 years) and older (n = 44, 60–80 years) adults.

Results. Older adults had lower antibody concentrations in saliva than young adults, with the most striking differences observed for salivary antibody secretion rates. In serum, older adults registered lower concentrations for only a minority of antibodies. Young adults who had previously received a polysaccharide pneumococcal vaccination (PPV23) had higher levels of anti-pneumococcal antibodies in serum and in saliva. Only minor differences were observed in antibody levels between older adults who had/had not received PPV23, and there was no evidence of memory in saliva.

Conclusions. Age differences were much greater in salivary antibodies than in serum; older adults had reduced salivary secretion rates of antibodies across bacterial antigens. This decline in local immunity may contribute to increased infection risk in the elderly. The poor memory from pneumococcal vaccination in serum and saliva suggests that PPV23 may be ineffective in older adults for both systemic and local protection.

Details

Original languageEnglish
Pages (from-to)1578-1585
Number of pages8
JournalThe journals of gerontology. Series A, Biological sciences and medical sciences
Volume70
Issue number12
Early online date31 Aug 2015
Publication statusPublished - 2015

Keywords

  • Immune Function, Infection, Bacteria