T cell populations in the lacrimal gland during aging

Abstract

The present study examined the influence of age and gender on T cell populations in the lacrimal gland. Lacrimal (exorbital) glands were obtained from male and female rats at 19 days (pre-puberty), 9 weeks (adult) and 14 months (mid-life) of age and tissues were processed for T cell subset identification. In females, the density of total (W3/13+ and OX 19+), helper/inducer (W3/25+) and suppressor/cytotoxic (OX 8+) T cells underwent a significant increase in tissues from before, to after puberty. Following this rise, the density of all T cell populations decreased in glands from young adult to midlife females. This pattern of accumulation contrasted with the T cell profile presented by glands from males: T cell densities appeared unaffected from 19 days to 9 weeks of age, and then either declined (OX 19+, W3/25) or remained unchanged (W3/13+, OX 8+) in tissues of 14 months rats. An influence of gender on the distribution of T cells was also apparent if results were corrected for age-associated variations in lacrimal gland weight. Thus, the absolute number of all T cell populations rose dramatically in glands of both sexes from pre- to post-puberty. However, from 9 weeks to 14 months of age, the total content of W3/13+, OX 19+, W3/25+ and OX 8+ lymphocytes decreased 2-fold in glands of females, but did not vary in tissues of males. Of interest, the number of W3/25+ and OX 8+ cells was analagous in all age groups examined. Moreover, the combined total of W3/25+ and OX 8+ cells was greater than that of W3/13+ or OX 19+ cells at every age. Overall, these results demonstrate that age has a significant impact on the lymphocytic density in the lacrimal gland. In addition, our findings show that gender may influence the lymphocyte profile in lacrimal tissue.