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Isolation of Leukocytes from the Human Maternal-fetal Interface
Published on: May 21, 2015
Immunomorphologic studies of human decidua-associated lymphoid cells in normal early pregnancy
L Mincheva-Nilsson1, V Baranov, M M Yeung
1Department of Immunology, University of Umeå, Sweden.
Insights
Human decidual lymphocytes, including gamma delta T cells, were studied in early pregnancy. Activated immune cells in large lymphoid cell clusters suggest a role in protecting the fetus and modulating maternal immune responses.
Area of Science:
- Immunology
- Cell Biology
- Reproductive Biology
Background:
- The maternal decidua houses a unique immune cell population crucial for successful pregnancy.
- Understanding decidual lymphocyte subsets and their interactions is key to reproductive health.
Purpose of the Study:
- To characterize the ultrastructure and distribution of human decidual lymphocyte subsets in early pregnancy.
- To investigate the morphology and activation status of decidual gamma delta T cells.
Main Methods:
- In situ characterization of decidual lymphocytes using electron microscopy and immunophenotyping.
- Ultrastructural analysis of isolated decidual gamma delta T cells.
Main Results:
- Decidual lymphocytes, primarily T and NK cells, were found in large lymphoid cell clusters (LCC) and as intraepithelial lymphocytes (IEL).
- Activated T cells (TCR-gamma delta+, TCR-alpha beta+, CD4+, CD8+) expressing activation markers and MHC class II antigens were abundant.
- Intraepithelial lymphocytes were predominantly activated TCR-gamma delta+ cells, interacting with glandular epithelial cells expressing heat shock protein 60.
Conclusions:
- Large lymphoid cell clusters serve as sites of immune activation within the decidua.
- Activated decidual lymphocytes, particularly gamma delta T cells, may protect against infection and trophoblast invasion.
- These immune cells likely contribute to maternal immune tolerance of the semi-allogeneic fetus.
Abstract:
Human decidual lymphocytes from early, normal pregnancy were characterized in situ with respect to ultrastructure and distribution of subsets. The ultrastructure of isolated decidual gamma delta T cells was also studied. CD45+ cells comprised 11 +/- 2% of all decidual cells. The majority were localized in large lymphoid cell clusters (LCC), near endometrial glands, or as intraepithelial lymphocytes (IEL) in glandular epithelium. The major cell populations in LCC were CD56+TCR-gamma delta+ cells, CD56+ cells, TCR-alpha beta+CD4+ cells, and TCR-alpha beta+CD8+ cells. All expressed activation markers (CD45RO, Kp43, and/or HML-1) and MHC class II Ag (HLA-DR, HLA-DP, and/or HLA-DQ). No B cells were found. Almost all IEL were activated TCR-gamma delta+ cells (CD56+ and CD56-). The glandular epithelial cells expressed heat shock protein 60 at the basolateral side facing the TCR-gamma delta+ IEL. Decidual lymphocytes displayed cytoplasmic processes, microvilli, characteristic cytoplasmic granules, and had intimate contact with neighboring cells. Lymphocytes in the outer rim of LCC and the stroma showed signs of cellular movement. Two main morphotypes of gamma delta T cells could be distinguished. One had single microvilli, membrane-bound granules, and nuclear inclusions. The other had many microvilli, nonmembrane-bound granules and cytoplasmic multivesicular bodies. Our data suggest that LCC are centers of immune reactivity where T and NK cells become activated. The activated cells may guard against infections and undue trophoblast invasion and/or be involved in modulating the local maternal immune system toward unresponsiveness against the semiallogeneic fetus.
