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Published on: August 9, 2019
Immunoelectron microscopy of cell populations in regional and central lymph of sheep
Y Otsuki1, S Magari, A Rolinson
1Department of Anatomy, Osaka Medical College, Japan.
Insights
This study examined sheep lymphocyte populations in lymph using monoclonal antibodies. Results reveal distinct immune cell distributions across different lymph sites, with unique findings in pregnant uterine lymph.
Area of Science:
- Immunology
- Cell Biology
- Veterinary Science
Background:
- Understanding lymphocyte distribution in lymph is crucial for immune response studies.
- Sheep lymphocytes play a key role in immune surveillance and response.
Purpose of the Study:
- To investigate the immunoreactivity and ultrastructural localization of lymphocyte subpopulations in sheep lymph.
- To analyze the distribution of T cells (CD4, CD8, CD5) and B cells in various lymph compartments.
Main Methods:
- Utilized monoclonal antibodies (SBU-T1, SBU-T4, SBU-T8, SBU-II, E53) conjugated with colloidal gold.
- Examined cells from thoracic duct, popliteal, mesenteric, and uterine prenodal lymph.
- Performed ultrastructural localization using electron microscopy.
Main Results:
- CD5+ lymphocytes were abundant in all examined lymph regions.
- CD4+ cells outnumbered CD8+ cells, with CD8+ cell immunoreactivity varying by region.
- A CD5+, CD4-, CD8- T cell subpopulation was identified.
- Uterine prenodal lymph in pregnant sheep showed a high percentage of CD8+ cells and abnormal eosinophils.
Conclusions:
- Lymphocyte distribution varies significantly depending on the lymph's organ site of origin.
- Specific immune cell profiles exist in different lymph compartments, including unique findings in pregnant uterine lymph.
- The study highlights regional differences in immune cell populations within the sheep lymphatic system.
Abstract:
The immunoreactivity and the ultrastructural localization of monoclonal anti-sheep lymphocyte antibodies conjugated with colloidal gold particles were examined in free-floating cells of sheep central lymph from the thoracic duct, postnodal lymph draining either the popliteal nodes or the mesenteric nodes, and prenodal lymph draining the pregnant uterus. The monoclonal antibodies used in this study were SBU-T1 (CD5), SBU-T4 (CD4), SBU-T8 (CD8), SBU-II (anti DR antibody), and E53 which are reported to be sheep homologues of human T1, T4, T8, HLA-DR, and pan B cell antibodies, respectively. Colloidal gold particles were evenly distributed or segmentally aggregated on the surfaces of lymphocytes and macrophages incubated with monoclonal antibodies and in vesicles in the cytoplasm of anti DR antibody labeled macrophages. Not only did CD5 labeled cells show a high percentage in each regional lymph examined, but the percentage of CD4 labeled cells was consistently higher than that of CD8 labeled cells. Moreover, the immunoreactivity of CD8 labeled cells was specific among lymph from the different regions. The sum of the percentages of CD4 and CD8 labeled cells was less than the percentage of CD5 labeled cells, indicating the presence of a minor T cell subpopulation which was CD5+, CD4-, and CD8-. A characteristic finding was a high percentage of CD8 labeled cells and many abnormal eosinophils in uterine prenodal lymph in pregnant sheep. Taken together the results showed that variously labeled immunoreactive cells are distributed somewhat differently in lymph derived from different organ sites.
