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Selective expression of CD8 alpha (Ly-2) subunit on activated thymic gamma/delta cells
H R MacDonald1, M Schreyer, R C Howe
1Ludwig Institute for Cancer Research, University of Lausanne, Epalinges, Switzerland.
European Journal of Immunology
|April 1, 1990
Summary
Most T cell receptor (TcR) gamma/delta cells are CD4-CD8-, but some express CD8. Activated mouse thymic gamma/delta cells express CD8 alpha as a homodimer, unlike conventional alpha/beta T cells.
Area of Science:
- Immunology
- T cell biology
- Cellular immunology
Background:
- Most T cell receptor (TcR) gamma/delta cells lack CD4 and CD8 co-receptors.
- A subset of gamma/delta T cells can express CD8, but the specific subunits and their assembly are not fully characterized.
Purpose of the Study:
- To investigate the expression and composition of CD8 on activated mouse thymic gamma/delta T cells.
- To compare CD8 expression in gamma/delta T cells with conventional alpha/beta T cells.
Main Methods:
- In vitro activation of mouse thymic T cells using concanavalin A.
- Flow cytometry staining with monoclonal and polyclonal antibodies against CD8 alpha (Ly-2) and CD8 beta (Ly-3) subunits.
- Immunoprecipitation and reduced/nonreduced gel electrophoresis to analyze CD8 subunit composition.
Main Results:
- Activated mouse thymic gamma/delta T cells express CD8.
- These cells exclusively express the CD8 alpha subunit.
- CD8 alpha is expressed as a homodimer (CD8 alpha/alpha) on activated gamma/delta T cells.
- In contrast, activated alpha/beta T cells express the conventional CD8 alpha/beta heterodimer.
Conclusions:
- Mouse thymic gamma/delta T cells can be induced to express CD8 upon activation.
- Activated gamma/delta T cells utilize a unique CD8 alpha homodimer, distinct from the alpha/beta T cell CD8 alpha/beta heterodimer.
- This finding highlights heterogeneity in CD8 co-receptor usage between different T cell lineages.