Molecular analysis of skewed Tcra-V gene use in T-cell receptor β-chain transgenic mice

As a consequence of the peptide specificity of intrathymic positive selection, mice transgenic for a rearranged TCR β-chain derived from conventional αβ T lymphocytes frequently carry mature T cells with significant skewing in the repertoire of the companion α-chain. To assess the generality of such an influence, we generated transgenic (Tg) mice expressing a β-chain derived from nonclassical, NK1.1+ αβ T cells, the thymus-derived, CD1.1-specific DN32H6 T cell hybridoma. Results of the sequence analysis of genomic DNA from developing DN32H6 β Tg thymocytes revealed that the frequency of the parental α-chain sequence, in this instance the Vα14-Jα281 canonical α-chain, is specifically and in a CD1.1-dependent manner, increased in the postselection thymocyte population. In accordance, we found phenotypic and functional evidence for an increased frequency of thymic, but interestingly not peripheral, NK1.1+ αβ T cells in DN32H6 β Tg mice, possibly indicating a thymic determinant-dependent maintenance. Thus, in vivo expression of the rearranged TCR β-chain from a thymus-derived NK1.1+ Vα14+ T cell hybridoma promotes positive selection of thymic NK1.1+ αβ T cells. These observations indicate that the strong influence of productive β-chain rearrangements on the TCR sequence and specificity of developing thymocytes, which operates through positive selection on self-determinants, applies to both classical and nonclassical αβ T cells and therefore represents a general phenomenon in intrathymic αβ T lymphocyte development.

mentioning

confidence: 78%

A NK1.1+ Thymocyte-Derived TCR β-Chain Transgene Promotes Positive Selection of Thymic NK1.1+ αβ T Cells

Viret

Lantz

et al. 2000

“…Alternatively, the prevalence of particular TCRab combinations could arise through enrichment of particular TCRs during the process of thymic positive selection (34,(60)(61)(62) and creating MHC-specific TCRs (37). Biased ab-chain pairing is observed in peripheral TCR repertoires from a number of singlechain TCR transgenic mice (60,63,64), suggesting that constraints on ab pairing may be a key determinant in shaping the composition of TCR repertoires.…”

Section: Discussionmentioning

confidence: 99%

Fixed Expression of Single Influenza Virus–Specific TCR Chains Demonstrates the Capacity for TCR α– and β–Chain Diversity in the Face of Peptide–MHC Class I Specificity

Clemens

Doherty

Gruta

et al. 2015

The characteristics of the TCR repertoire expressed by epitope-specific CD8+ T cells can be an important determinant of the quality of immune protection against virus infection. Most studies of epitope-specific TCR repertoires focus solely on an analysis of TCR β-chains, rather than the combined TCRαβ heterodimers that confer specificity. Hence, the importance of complementary α- and β-chain pairing in determining TCR specificity and T cell function is not well understood. Our earlier study of influenza-specific TCR repertoires in a C57BL/6J mouse model described a structural basis for preferred TCRαβ pairing that determined exquisite specificity for the DbPA224 epitope from influenza A virus. We have now extended this analysis using retrogenic mice engineered to express single TCR α- or β-chains specific for the DbNP366 or DbPA224 epitopes derived from influenza A virus. We found that particular TCRαβ combinations were selected for recognition of these epitopes following infection, indicating that pairing of certain α- and β-chain sequences is key for determining TCR specificity. Furthermore, we demonstrated that some TCRαβ heterodimers were preferentially expanded from the naive repertoire in response to virus infection, suggesting that appropriate αβ pairing confers optimal T cell responsiveness to Ag.

“…These took advantage of a propensity of the ␤-chain to pair with ␣-chains similar to that with which it was paired in the hybridoma of origin (15,23). This identifies a stage that can be referred to as ␣ selection.…”

Section: Analysis Of Tcr V ␣-Chain Genes During Thymocyte Maturationmentioning

confidence: 99%

Thymocyte Maturation: Selection for In-Frame TCR α-Chain Rearrangement Is Followed by Selection for Shorter TCR β-Chain Complementarity-Determining Region 3

Yassai

Gorski

2000

Thymocyte maturation consists of a number of stages, the goal of which is the production of functioning T cells that respond to foreign antigenic peptides using their clonotypic receptors. Selection of a productively rearranged TCR β-chain is the first stage in the process and occurs at the double-negative to double-positive (DP) transition. Later maturation stages are based on changes in markers such as CD5, CD69, or IL-7R. A stage in which α-chains are selected has also been identified using β-chain transgenic mice. Here we identify two additional selection stages in human thymocytes based on characteristics of the TCR. α selection is measured directly by identification of in-frame rearrangements and is associated with the appearance of CD3 on the DP thymocyte surface. The next stage has not yet been described and involves selection of thymocytes that express shorter TCR β-chain complementarity-determining region 3 (CDR3). This stage is associated with the acquisition of high levels of CDR3 by DP cells and the transition to SP thymocytes. The extent of CDR3 length selection observed is a function of the TCR V and J genes. We propose that CDR3 length selection is based on recognition of the MHC. Thus, there exist limitations on the allowable length of that portion of the TCR most intimately in contact with MHC and peptide. This may be a physical representation of positive selection.