Effects of ageing and oestrogen on the localization of immunoglobulin-containing cells in the chicken ovary.

Immunoglobulins in the chicken ovary are important for transfer of immunity to chicks through the egg and for protection of the ovary from infection. The aim of this study was to examine the effects of ageing and oestrogen on the population of Ig-containing cells in the chicken ovary. The ovarian tissue of immature, young laying and old laying hens and that of immature birds treated with diethylstilboestrol (DES), progesterone or sesame oil (vehicle) was processed for paraffin wax sections. The sections were stained for IgG, IgM and IgA by an indirect immunostaining method and the population of cells positive for each Ig was analysed under a light microscope. The number of cells positive for IgG, IgM and IgA was significantly greater in the ovarian stromal tissue of young laying hens than in immature or old laying hens (P < 0.01). The number of IgG- and IgM-positive cells in the thecal layer of primary follicles of young laying hens was significantly greater than that in immature and old laying hens (P < 0.01) and there were significantly more (P < 0.05) IgA-positive cells in young laying hens than in immature birds. The number of IgG-, IgM- and IgA-positive cells was significantly (P < 0.01) greater in both the stromal tissue and the thecal layer of DES-treated birds than in the vehicle-treated birds. Progesterone had no significant effect (P < 0.05) on the population of Ig-positive cells. These results indicate that the number of Ig-positive cells increases as chickens mature and decreases with ageing, and that oestrogen may be involved in this process.