Journal of Dental Research, Vol 66, 451-456, Copyright © 1987 by International & American Associations for Dental Research Online Journals
Ontogeny and senescence of salivary immunity
D. J. Smith, M. A. Taubman and J. L. Ebersole
The objective of the present study was to evaluate the capacity for
secretory immune responses throughout life. This was done by measuring, by
single radial immunodiffusion, the concentrations of IgA and IgA1 subclass
in saliva samples of subjects who ranged in age from two months to 91
years. The presence of salivary IgA antibodies to two nearly ubiquitous
mucosal antigens, Streptococcus mutans glucosyltransferase (GTF) and killed
poliovirus (Types 1, 2, and 3), was measured in an enzyme-linked
immunosorbent assay in this population. Whole saliva from 2-5-month-old
infants contained significantly less IgA than did parotid saliva of any
adult group. Also, a significantly higher proportion of the total salivary
IgA was IgA1 in infants' saliva than was found in parotid saliva of adults.
Salivary IgA and IgA1 subclass levels in parotid saliva of young and old
(70-91 years) adults did not differ. Salivary IgA antibody levels to GTF
were negligible in most saliva samples of children less than five years
old, while 40% of children older than one year had detectable levels of
salivary antibody to poliovirus (PV). This differences between response to
GTF and PV antigens may reflect differences in antigenic challenge. Parotid
saliva of the oldest group (70-91 years) had narrowly distributed and
uniformly low levels of IgA antibody to both antigens. Since their IgA
immunoglobulin levels were the same as in younger adults, the low antibody
levels in this oldest group may be associated with changes in the number or
function of T or B lymphocytes or antigen-processing cells, and/or may
result from diminished levels of challenge with these antigens.
