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Inhibition of gamma delta T cell recognition by receptors for MHC class I molecules
H Nakajima1, H Tomiyama, M Takiguchi
1Department of Tumor Biology, University of Tokyo, Japan.
Insights
Gamma delta T cells, like NK cells, possess inhibitory receptors for MHC class I molecules. These receptors regulate immune responses by controlling T cell cytotoxicity against target cells.
Area of Science:
- Immunology
- Cellular Biology
Background:
- Natural Killer (NK) cells utilize receptors for Major Histocompatibility Complex (MHC) class I molecules to inhibit their cytotoxic activity.
- Gamma delta T cells represent a distinct T cell subset with unique immune surveillance functions.
Purpose of the Study:
- To investigate whether gamma delta T cells also possess inhibitory receptors for MHC class I molecules.
- To determine the role of these receptors in regulating gamma delta T cell-mediated cytotoxicity.
Main Methods:
- Utilized gamma delta T cell clones and C1R cells (a target cell line).
- Assessed cytotoxicity inhibition by polymorphic Human Leukocyte Antigen (HLA) class I molecules on target cells.
- Employed blocking with anti-HLA class I monoclonal antibodies (mAbs) to investigate receptor involvement.
Main Results:
- Expression of polymorphic HLA class I molecules on target cells inhibited cytolysis mediated by gamma delta T cell clones.
- Blocking these HLA class I molecules with anti-HLA class I mAbs restored gamma delta T cell cytotoxicity.
- Demonstrated heterogeneity in the types of receptors for HLA class I molecules expressed on gamma delta T cells.
Conclusions:
- Gamma delta T cell recognition and cytotoxicity are negatively regulated by receptors for MHC class I molecules.
- These inhibitory receptors on gamma delta T cells are diverse.
- Immune responses to various antigens may be modulated through these inhibitory receptors on both T cells and NK cells.
Abstract:
NK cells have receptors for MHC class I molecules that inhibit cytotoxicity against target cells. We show that recognition of gamma delta CTL is negatively regulated by receptors for MHC class I molecules. Cytolysis of C1R cells by gamma delta CTL clones was inhibited by the expression of polymorphic HLA class I molecules on target cells and was restored by blocking with anti-HLA class I mAb, suggesting the presence of inhibitory receptors for HLA class I molecules. The receptors for HLA class I molecules on gamma delta T cells were heterogenous. The immune responses to various Ags may be regulated via these inhibitory receptors on T cells and NK cells.