Figure 4.

Kinetics of accumulation of interferon-γ (IFN-γ)-producing CD4 cells in the lungs of mice infected via the airborne route, intravenous (i.v.) route, or both routes. (a) Mice infected via the i.v. route alone showed a substantial increase in the percentage of CD4 T cells in the lungs between days 6 and 15 of infection. Mice infected via both routes showed a large increase between days 6 and 20. By contrast, mice infected via the airborne route alone did not show a progressive increase until after day 15. (b) As with the increase in percentage, a progressive increase in the total number of IFN-γ-producing CD4 cells per lung was evident between days 6 and 15 in the case of mice infected via the i.v. route alone, between days 6 and 20 in mice infected via both routes, but not until after day 15 in mice infected via the airborne route. Means ± SD of four mice per group per time point.