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Selection of dual Valpha T cells
1Transplantation Biology Group, MRC Clinical Sciences Centre, Imperial College School of Medicine, Hammersmith Hospital, London, GB. jielliot@rpms.ac.uk
European Journal of Immunology
|August 6, 1998
Summary
Dual Valpha T cells arise from incomplete TCRa gene rearrangement. Thymic selection influences their frequency and expression, with inefficiently selected Valpha chains increasing co-expression likelihood.
Area of Science:
- Immunology
- T cell biology
- Gene rearrangement
Background:
- Incomplete allelic exclusion during T cell receptor alpha (TCRa) gene rearrangement can lead to dual Valpha T cells.
- The frequency and thymic selection of these dual Valpha T cells remain incompletely understood.
Purpose of the Study:
- To investigate the frequency and thymic selection mechanisms of dual Valpha T cells.
- To determine if both co-expressed Valpha chains participate in thymic selection processes.
Main Methods:
- Utilized lymphocytes from mice hemizygous at the TCRa locus as background controls.
- Analyzed the frequency and relative expression levels of co-expressed Valpha chains.
- Examined differences in Valpha chain expression between CD4 and CD8 T cell subsets.
Main Results:
- Dual Valpha T cell frequency and Valpha chain expression levels are variable and thymic selection-dependent.
- Inefficient positive selection of one Valpha chain increases the probability of co-expression of a second Valpha chain.
- Dual Valpha T cells do not appear to be frequent among immature thymocytes, contrary to prior reports.
Conclusions:
- Thymic selection plays a critical role in regulating the generation and expression profiles of dual Valpha T cells.
- The co-expression of Valpha chains is influenced by their individual selection efficiencies and T cell subset.
- Dual Valpha T cells are not a predominant population in immature thymocytes.