Phenotypic and functional cellular differences between human CD3- decidual and peripheral blood leukocytes

Area of Science:

• Immunology
• Cell Biology
• Reproductive Immunology

Background:

• Human decidualized endometrial tissue contains CD3- leukocyte clones with distinct phenotypes compared to peripheral blood lymphocyte (PBL) clones.
• These decidual granulated leukocyte (DGL) clones possess natural killer (NK) cell activity, but their functional characteristics, particularly in relation to target cell expression of MHC molecules, require detailed investigation.

Purpose of the Study:

• To compare the characteristics of CD3- DGL clones with CD3- PBL clones.
• To investigate the NK cell activity of DGL clones against various target cells, including those expressing specific HLA molecules.
• To examine the immunomodulatory effects of DGL on mixed lymphocyte reactions (MLR).

Main Methods:

• Isolation and characterization of CD3- leukocyte clones from human decidualized endometrial tissue and peripheral blood.
• Assessment of cytotoxic activity against NK-resistant cell lines and target cells with varying HLA expression.
• Evaluation of the effects of CD3- DGL on one-way mixed lymphocyte reactions (MLR).

Main Results:

• CD3- DGL clones were predominantly CD16- CD56+, unlike CD3- PBL clones (mostly CD16+ CD56+).
• Both DGL and PBL clones displayed MHC-nonrestricted NK cell activity.
• CD3- DGL clones showed potent cytotoxicity against HLA-negative cells, but HLA-G expression on target cells reduced killing. DGL also suppressed MLR.

Conclusions:

• CD3- DGL clones possess significant MHC-nonrestricted cytotoxic activity, particularly against HLA-deficient cells.
• Expression of HLA-G by target cells confers protection against DGL-mediated lysis.
• CD3- DGL may play a role in immune suppression within the maternal-fetal interface, potentially modulating allogeneic responses.