Changes in the population of lymphocytes expressing CD4 and CD8 during the process of atresia of white follicles in hens

2004

Animal Science Journal

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The current paper describes aspects of local immunity in the ovary and oviduct, and the significance of immunity to reproductive functions in hens. The immunocompetent cell populations in the ovary and oviduct change with a positive correlation to sexual activity, and gonadal steroid is one of the key factors in the increase. Local immune responses mediated by major histocompatibility complex class II and T cell subsets occur in response to infection by Salmonella enteritidis , which may contaminate eggs. In the ovary, immunocompetent cells are also suggested to play roles in the regulation of ovarian functions. Macrophages and T cells are likely to enhance the regression of atretic follicles to maintain the ovarian tissue microenvironment. Autoantibodies to ovarian tissues appeared in the hens with low egg laying frequency, suggesting that the auto-antibodies may be one of the factors in the decline of egg production. In the oviduct, local immunity possibly has a role in the selection of sperm, though the immunoreactions may also affect sperm survival leading to the decline in fertility. The concentration of yolk IgY, which plays a role in maternal immunity transmission, significantly decreases with the aging of birds, whereas it is significantly increased by estrogen. Therefore, the immune system plays significant roles not only in defense against infection, but also in the functions of reproductive organs. Investigations on the local immune system in the reproductive organs and factors affecting it are of importance for the production of sterile eggs and improvement of reproductive functions.

Section: Significance Of Immunity To Ovarian Functionsmentioning

confidence: 99%

Section: Significance Of Immunity To Ovarian Functionsmentioning

confidence: 99%

Significance of local immunity in hen reproductive organs

2004

Animal Science Journal

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Ovarian Cell-Mediated Immune Response to Salmonella enteritidis Infection in Laying Hens (Gallus Domesticus)

Barua

2004

Poultry Science

The aim of this study was to examine the response of cell-mediated ovarian immunity against Salmonella infection in hens. Laying hens were injected intraperitoneally with PBS (control) or Salmonella enteritidis (SE). Ovarian stroma containing stromal follicles, small white follicles (SWF), and third largest (F3) and the largest (F1) follicles were collected 12 or 24 h after inoculation and fixed in periodate-lysine-paraformaldehyde. Frozen sections were stained first for CD3+, CD4+, or CD8+ T cells and then for SE by a double immunostaining method. Immunoreaction products for SE were detected in the ovarian stroma, theca of stromal follicles, SWF, F3, and F1 at 12 and 24 h after inoculation. Immunopositive T-cell subsets were localized in the stroma and theca of follicles in birds inoculated with or without SE. The populations of CD3+, CD4+, and CD8+ T cells were significantly greater in the stroma and the theca of follicles 12 h after SE inoculation than in those of control birds (P< 0.01). Their frequencies were further increased in those tissues 24 h after inoculation (P < 0.01). Injection of SE did not cause significant differences in the CD4+:CD8+ T-cell ratio as both subsets increased proportionately. The current results indicate that the population of T-cell subsets increases in the ovarian stroma and the follicular tissues in response to SE invasion within 12 h of inoculation. Thus, cell-mediated immune response against SE, their products, or both may be induced in the hen ovary.

Changes in Localization of T Cell Subsets in the Ovarian Follicles during Follicular Growth and Ovulation in Hens

Subedi

2005

J. Poult. Sci.

Changes in the localization of helper and killer T cells (CD. ῌ and CD2 ῌ T cells, respectively) in hen ovarian follicles with follicular growth and ovulation were examined in this experiment. White follicles (WF), the largest and the third largest preovulatory follicles (F+ and F-, respectively) and the largest postovulatory follicle (POF) were collected from birds after / hrs of oviposition. Cryostat sections were prepared and immunostained for T cells using antibodies to CD. (antigen of helper T cells) and CD2 (antigen of cytotoxic T cells). Populations of positive cells were observed under a light microscope and counted using a computer assisted image analyzer. The CD. ῌ and CD2 ῌ T cells were localized in the theca interna and externa of all examined follicles. The frequencies of CD. ῌ and CD2 ῌ T cells in the theca interna were similar among each type of follicles. The frequency of CD. ῌ T cells in the theca externa was significantly decreased in Fand F+ compared with WF, with a further decrease in POF (P῍*.*/), and that of CD2 ῌ T cells was lower in F-, F+ and POF than WF (P῍*.*+). The ratio of CD. ῌ /CD2 ῌ T cells in the theca interna was similar among each type of follicles but significantly lower in the theca externa of POF than WF, Fand F+ (P῍*.*/). These results suggest that the T cell subsets, responsible for cell mediated immunity, are reserved in the theca layer of ovarian follicles, whereas their population decreases with follicular growth in theca externa.