Related Experiment Video
Updated: Jul 14, 2026

Use of Single Chain MHC Technology to Investigate Co-agonism in Human CD8+ T Cell Activation
Published on: February 28, 2019
CD8alpha/alpha homodimers fail to function as co-receptor for a CD8-dependent TCR
Anne-Marie McNicol1, Gavin Bendle, Angelika Holler
1Department of Immunology and Molecular Pathology, University College London, London, UK.
T-cell receptor (TCR) genes dictate CD8 dependence in cytotoxic T lymphocytes (CTLs). CD8beta-chain is crucial for CD8-dependent TCR function, highlighting differences between CD8alpha/beta and CD8alpha/alpha dimers.
Area of Science:
- Immunology
- Molecular Biology
- Cellular Biology
Background:
- Cytotoxic T lymphocytes (CTLs) play a critical role in adaptive immunity.
- CD8 co-receptor function is essential for efficient CTL activation and effector functions.
- The molecular basis for varying CD8 dependence among CTLs recognizing the same antigen is not fully understood.
Purpose of the Study:
- To investigate the molecular mechanisms underlying CD8 dependence in high and low avidity CTL clones.
- To determine if CD8 dependence is an intrinsic property of the T-cell receptor (TCR) or influenced by other cellular factors.
- To elucidate the distinct roles of CD8alpha/beta heterodimers and CD8alpha/alpha homodimers in CTL function.
Main Methods:
- Utilized anti-CD8alpha and anti-CD8beta antibodies to assess CTL cytotoxicity and IFN-gamma production.
- Isolated TCR genes from high and low avidity CTL clones.
- Employed retroviral gene transfer to express TCRs in primary T cells from wild-type and CD8beta-deficient mice.
Main Results:
- High avidity CTLs exhibited strong CD8 dependence for cytotoxicity and IFN-gamma production, unlike low avidity CTLs.
- CD8 dependence/independence was transferable with the TCR, indicating TCR intrinsic control.
- TCR from CD8-dependent CTLs required the CD8beta-chain for function in CD8beta-deficient T cells, while the CD8-independent TCR functioned without it.
Conclusions:
- TCRs intrinsically determine CD8 dependence in CTLs.
- The CD8beta-chain is essential for the function of CD8-dependent TCRs.
- CD8alpha/beta heterodimers provide co-receptor function for CD8-dependent TCRs, whereas CD8alpha/alpha homodimers do not.
More Related Videos
09:53Using X-ray Crystallography, Biophysics, and Functional Assays to Determine the Mechanisms Governing T-cell Receptor Recognition of Cancer Antigens
Published on: February 6, 2017
10:13Tailoring In Vivo Cytotoxicity Assays to Study Immunodominance in Tumor-specific CD8+ T Cell Responses
Published on: May 6, 2019
Related Concept Videos
T Cell Activation and Clonal Selection
Naive T cells that have not yet encountered an antigen express two primary CD...
Diversity of Antigen Receptors
Before encountering any antigen, lymphocytes express these receptors. On B cells, the antigen receptor is a membrane-bound antibody molecule called BCR; on T cells, it is a T cell receptor or TCR. B and T cell receptors are composed of two...
Cytotoxic T Cells-mediated Immune Response
Immunological surveillance is the ability of immune cells to monitor and eliminate infected cells with intracellular pathogens, neoplastically transformed cells, and cells with non-self antigens. Cytotoxic T cells and NK...
T Cell Types and Functions
Th1 cells stimulate dendritic cells to express necessary co-stimulatory molecules on their surfaces for...
Antigens Involved in Adaptive Immunity
Complete Antigens
Complete antigens possess both immunogenicity and reactivity.
Cells of the Adaptive Immune Response