Fig. 5.
T cell activation is reduced in the presence of high numbers of T cells. Recipient mice were immunized by footpad injection of 1.5 × 106 SNARF-labeled DCs pulsed with either 100 nM (a) or 10 nM (b) Dby peptide. After 2–4 h, recipients were adoptively transferred with 1 × 106 or 10 × 106 CFSE-labeled naïve Marilyn CD4 T cells. At various time points, popliteal lymph nodes were harvested and lymph node cells were analyzed by flow cytometry. Data are gated on CD4+CD45.1+ cells. At high T cell precursor frequency, T cell activation and proliferation were markedly reduced on a per-cell basis. Results are representative of three independent experiments.