Figure 7. CVB3 infection induces the in vivo proliferation of virus-specific CD4⁺, but not CD8⁺, transgenic T cells.

(A) Equal numbers (6×10⁵) of P14 and SMARTA cells from uninfected mice were labeled with CFSE, combined, and transferred into uninfected recipients. One day post transfer, mice were infected with rCVB3.6 or LCMV, or were not infected. Eight days later, P14 and SMARTA responses in the spleen were analyzed by flow cytometry. The square gates in the dot plots identify P14 or SMARTA cells, and the numbers shown are the percentages of transgenic cells among mononuclear cells. The histograms of CFSE fluorescence are gated on P14 or SMARTA cells. Data are representative of 3 mice per group. (B) Mice were inoculated with rCVB3.2, 3.3, 3.4, or 3.5. Two days after infection, naïve P14 and SMARTA cells were labeled with CFSE, and 9×10⁵ transgenic T cells (P14 or SMARTA) were injected i.v. into the infected mice. Eight days post transfer (10 days p.i.) the P14 or SMARTA cells were identified by flow cytometry (ovals within dot plots). The histograms show the level of CFSE fluorescence by the donor cells. As a positive control, the CFSE-labeled transgenic T cells were given to uninfected mice; the following day these mice were infected with LCMV, and 7 days later these cells were identified (bottom row, dot plots) and their near-total loss of CFSE-fluorescence was revealed (bottom row, histograms).