Figure 1.

aDC depletion at 48 h p.i. results in reduced numbers of IAV-specific CD8 T cells in the lungs on days 4 and 5 p.i. (A) Groups of mice were infected with either a sublethal dose of IAV, influenza type B, or the A2 strain of RSV. One group of mice remained uninfected. On day 4 p.i., the mice were sacrificed and their lungs were analyzed by flow cytometry for the frequencies of influenza NP₁₄₇-specific and RSV M2₈₂-specific tetramer⁺ CD8 T cells. Representative FACS plots are gated on CD3⁺CD8⁺ T cells. Data are representative of one experiment (n = 2–3 mice/group). (B and C) Groups of BALB/c mice were infected with a sublethal dose of IAV. Half of the mice were aDC depleted at 48 h p.i. (aDC depleted), whereas the other half remained nondepleted (control). On days 4 and 5 p.i., the frequency (B) and number (C) of antigen-specific tetramer⁺ CD8 T cells in the lungs were enumerated. Representative FACS plots are gated on CD3⁺CD8⁺ T cells. Numbers of tetramer⁺ CD8 T cells in the lungs were determined by subtracting background staining using the media control (B, top). Data are pooled from two separate experiments and represent means ± SEM (n = 5–9 mice/group). (D and E) Influenza-specific, CD90.2⁺ CL-4 T cells were adoptively transferred to groups of CD90.1⁺ BALB/c mice as described in Materials and methods. 24 h later, mice were infected with a sublethal dose of IAV. Half of the mice were aDC depleted at 48 h p.i. (aDC depleted), whereas the other half remained nondepleted (control). On days 4 and 5 p.i., the frequency (D) and number (E) of CD90.2⁺, adoptively transferred CL-4 T cells were determined by flow cytometry. Representative FACS plots are gated on CD3⁺CD8⁺ T cells. Data are representative of three separate experiments and represent means ± SEM (n = 3–4 mice/group).