Figure 5. The role of CD4 T cell help in primary and secondary responses during acute versus chronic infection.

1×10³ of each memory (Thy1.1⁺1.2⁺) and naïve (Thy1.1⁺1.2⁻) P14’s were co-transferred with or without 1×10⁶ LCMV-GP61 specific CD4 T cells (Smartas) into naïve mice. The next day mice were infected with either an acute (2×10²) or chronic (2×10⁶) dose of LCMV cl-13.(A) Representative dot plot of naïve and memory P14 T cells in the spleen, liver and lung at day 6.5 p.i. (B) Numbers of naïve and memory P14 T cells in the spleen at day 6.5 p.i. (C) Percent of naïve and memory P14 T cells in blood at day 6.5 p.i. (D) Mice were set-up as in A–D and were treated with MR1 antibody or PBS on day −1,0,3 and 6 p.i. Numbers of naïve and memory P14 T cells in spleen at day 6.5 p.i. In the figures and legends, +CD4 help indicates mice receiving Smarta cells, − CD4 help indicates mice that do not receive Smarta cells. Results are representative of two (D) or three (A–C) independent experiments with 4–6 mice per group. ***p<0.005. Error bars represent SEM.