Effects of aging and sex steroids on the localization of T cell subsets in the ovary of chicken, Gallus domesticus.

The goal of this study was to determine the effects of aging and sex steroids on the frequency of T cells in hen ovary. Cryostat sections of ovarian tissues of immature and laying hens and those of immature hens treated with or without diethylstilbestrol (DES) or progesterone were immunostained for T cells using mouse anti-chicken CD3 (antigen of mature T cells), CD4 (antigen of helper T cells), and CD8 (antigen of cytotoxic T cells) monoclonal antibodies. Positive cells were observed under a light microscope and counted using a computer-assisted image analyzer. The frequency of CD3(+), CD4(+), and CD8(+) cells in the ovarian stroma and theca of primary follicles was significantly greater in young laying hens than in immature and old laying hens (P < 0.01). The CD4:CD8 ratio was significantly higher in the ovarian stroma of old laying hens than that of immature hens (P < 0.01), which was due to a greater decrease of CD8(+) cells than of CD4(+) cells. The frequency of CD3(+), CD4(+), and CD8(+) cells was significantly greater in the stroma and theca of primary follicles of DES-treated birds than in those of progesterone-treated and control birds (P < 0.01). Progesterone had no significant effect on the population of each subset of T cells. These results suggest that T cell frequency increases in association with sexual maturation and decreases thereafter during aging with an increase of CD4:CD8 ratio. Also, it is likely that estrogen is one of the factors which stimulates the influx of T cells in the hen ovary. Copyright 1999 Academic Press.