Localization and enumeration of T and B lymphocytes in the reproductive tract of laying hens.

Distribution and the relative frequencies of subclasses of T and B lymphocytes in the 360-d-old, healthy laying hens were studied. Avidin-Biotin-Peroxidase Complex (ABC) method was used to detect T cells, whereas Indirect Immunofluorescent Technique (IFT) was applied to detect B cells. Both T and B cells were scattered throughout the ovaries and oviducts. Small lymphoid nodules were found in the upper regions of the oviducts. More T lymphocytes were found in the vagina, ovary, and infundibulum than in the other portions examined, whereas B lymphocytes were mainly found in magnum, uterus, and isthmus. The IgG-containing (B) cells were not found in the ovary. The CD8+ cells were found more close to the lining epithelium or in between epithelial cells, whereas CD4+ cells were found mainly in the lamina propria. The behavior of these cells in certain infectious diseases in which the ovaries and oviducts are major predilection sites would be very important in assessing or determining local immune responses.