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Functional consequences of anti-sense RNA-mediated inhibition of CD8 surface expression in a human T cell clone
J E Hambor1, M L Tykocinski, D R Kaplan
1Institute of Pathology, Case Western Reserve University, Cleveland, Ohio 44106.
Abstract:
An experimental approach for defining the function of CD8 has been developed by linking anti-sense RNA mutagenesis and T cell cloning technologies. We have transfected an anti-sense CD8 episomal expression vector into a CD8+ nontransformed human T cell clone that is specific for the human class I alloantigen HLA-B35. Expression of CD8 on this T cell clone, JH.ARL.1, was selectively and efficiently inhibited. Stimulation of this CD8- variant with specific alloantigen resulted in a marked loss of a number of functional responses, including cytotoxicity, proliferation, IL-2 secretion, and IL-2-R expression. However, these same functional responses could be elicited with stimuli that do not require antigen recognition to activate the T cell (anti-CD3 mAbs, PHA). The results of our study support the hypothesis that CD8 is required for recognition of class I MHC alloantigens that results in activation of T cell functional responses.
Insights
This study demonstrates that the CD8 molecule is essential for human T cell recognition of foreign class I MHC alloantigens. Inhibiting CD8 function impairs T cell responses like cytotoxicity and proliferation.
Area of Science:
- Immunology
- Molecular Biology
- Cell Biology
Background:
- The CD8 molecule is a co-receptor on T cells crucial for recognizing antigens presented by MHC class I molecules.
- Understanding the precise role of CD8 in T cell activation and function is vital for immunology research.
Purpose of the Study:
- To investigate the specific function of CD8 in T cell responses to human class I MHC alloantigens.
- To elucidate the role of CD8 in antigen recognition and subsequent T cell activation.
Main Methods:
- Utilized anti-sense RNA mutagenesis to selectively inhibit CD8 expression in a human T cell clone (JH.ARL.1).
- Employed T cell cloning technologies for precise genetic manipulation and functional assays.
- Stimulated CD8-deficient T cells with specific alloantigens and non-antigen-specific stimuli (anti-CD3 mAbs, PHA).
Main Results:
- Selective inhibition of CD8 expression was achieved using an anti-sense CD8 episomal expression vector.
- CD8-deficient T cells exhibited significantly reduced cytotoxicity, proliferation, IL-2 secretion, and IL-2-R expression upon specific alloantigen stimulation.
- Functional responses were restored when T cells were activated by non-antigen-specific stimuli, indicating CD8's role in antigen recognition.
Conclusions:
- CD8 is indispensable for the recognition of class I MHC alloantigens by human T cells.
- The co-receptor CD8 plays a critical role in mediating T cell activation and downstream functional responses during alloantigen recognition.