Therefore, Saracatinib supplier neither La nor Lb infection significantly altered TCR Vβ diversity in draining LN- and lesion-derived CD4+ T cells, although Lb infection showed greater increase in cell numbers. Because the percentages of IFN-γ-producing CD4+ T cells correlate with the disease outcomes in La- and Lb-infected mice (5), we collected draining LN cells at 4 weeks post-infection and performed intracellular IFN-γ staining, gating on each TCR Vβ+ subpopulation. It was evident that Lb infection triggered significantly stronger IFN-γ responses than did La infection, as judged by their frequencies of Vβ4-, 6- and 8.1/8.2–bearing

IFN-γ+ CD4+ T cells. For example, 0.78% of Vβ8.1/8.2–bearing CD4+ T cells produced IFN-γ in Lb-infected mice, whereas only 0.47% of these cells produced IFN-γ in La-infected mice (Figure 2a). However, neither La nor Lb infection changed the relative frequencies of Vβ+ IFN-γ+ cells among total IFN-γ+ cells (Figure 2b), and

Vβ 8.1/8.2–and Vβ4-bearing cells contributed to ∼20% and ∼8% of total IFN-γ production in all three groups check details of mice, respectively. Notably, draining LN from Lb-infected mice contained higher numbers of IFN-γ-producing TCR Vβ+ CD4+ T subsets than those from La-infected mice (Figure 2c). Therefore, although the relative contributions of individual Vβ+ CD4+ T cells to total IFN-γ production were comparable in both infection models, Lb infection apparently induced a higher magnitude of CD4+ T-cell activation and IFN-γ production than did

La infection. To confirm these flow cytometric Pembrolizumab research buy data, we analysed the oligoclonalities in the CDR3 region of 22 individual TCR Vβ chains by RT-PCR-based assays, in which multiple PCR primer sets were uniquely designed for specific amplification of the Vβ, Dβ or Jβ genes. We found that when compared to naïve controls, CD4+ T cells purified from La- and Lb-infected mice displayed multiple TCR Vβ clonalities based on VDJ rearrangement in the CDR3 region and that TCR Vβ clonalities were evident and strong in CD4+ T cells of Lb-infected mice (Supplemental Figure S1). Our FACS- and PCR-based studies suggest that in contrast to viral infection (23), primary infection with La or Lb parasites does not show a highly focused, selective expansion of particular Vβ population. We have previously reported that Lb infection in B6 mice is self-healing, with no signs of disease and detectable tissue parasites at 8 weeks (5). To test whether pre-infection with Lb could enhance CD4+ T-cell activation and protect mice against La infection, we infected mice with Lb parasites in one foot for 8 weeks (short-term) or 24 weeks (long-term) and then challenged these healed mice with La parasites in another foot.