In B6 mice, the prevalent DbPA224-specific clonotypes utilize Jβ1.1 or 2.6 and a 6 or 7 aa CDR3β 13, whereas clonotypes in the CD8+DbPAVβ7+ populations from A7 animals generally utilized sequences characterized by a 6 aa CDR3β loop and Jβ1.1, the pattern that is also dominant in the wt DbPACD8+ response. Thus, learn more though DbPAVβ7+CD8+ responses in A7 transgenics are less diverse, the overall TCRβ characteristics are conserved. To determine the extent of Vα2 expression, DbNPCD8+ and DbPACD8+ T cells obtained from the spleens and BAL populations of influenza-infected mice were stained for Vα2, tetramer,

and CD8. Although the DbNPCD8+ and DbPACD8+ T cells from B6 mice showed no evidence of Vα2 expression, the tetramer-specific CD8+ T cells from the A7 were Vα2+ (Fig. 4). However, since some (∼30%) of naïve TCRα transgenic T cells can rearrange their TCRα locus and express an endogenous Vα 26, we performed PCR analysis on DbNPCD8+ and DbPACD8+ T cells to determine whether any of these cells expressed additional Vα. Analysis of a panel of Vα elements showed transgenic Vα2 (CDR3α sequence SDNYQL) expression in DbNPCD8+ and DbPACD8+ T cells derived from six

different mice. The DbPACD8+ T cells did not express any additional Vα chains, whereas the DbNPCD8+ set expressed additional Vα1 sequences in two-thirds of mice (Supporting Information Table 1). This further supports our observations that TCRβ diversity of DbPACD8+ but not DbNPCD8+ T cells contributes to the ability to pair with an irrelevant Vα2. The published evidence suggests that only some (∼30%) naïve TCRα transgenic selleck products T cells rearrange their TCRα locus and express Kinase Inhibitor Library cost an endogenous Vα 26. Given the limited spectrum of TCRβ clonotypes identified for antigen-specific DbNPCD8+ (2.1±1.5 clonotypes/mouse) T cells and DbPACD8+ (5.3±3.4 clonotypes/mouse) T cells in A7 transgenics, the identification of endogenously rearranged Vα only in DbNPCD8+ T cells from two-thirds of mice tested is not altogether unexpected. Furthermore, our analysis of Vα elements was performed for 19 of the 23 Vα families studied. It is possible that some endogenous rearrangements

may have been missed. However, the emphasis of this analysis was to show that other Vα elements (such as Vα17, a preferred Vα element used by DbNPCD8+ cells and included in our analysis) are not directing TCR specificity. Though the A7 mice are still able to generate DbNPCD8+ and DbPACD8+ T-cell responses, the spectrum of CDR3β diversity is dramatically decreased for both populations. Do such reductions in TCRβ diversity and the “forced” pairing in transgenic A7 mice have any functional consequences for influenza-specific CD8+ T-cell responses? Assessment of tetramer staining (Fig. 1C–D, G–H) revealed that the mean fluorescence intensity (MFI) was lower for both the DbNPCD8+ and the DbPACD8+ sets from the A7 versus B6 mice (Fig.