Fig. 1.

LLO118 T cells have a better primary response, whereas LLO56 T cells have a better secondary response to L. monocytogenes infection. (A) CD4⁺ T cells from LLO118-Ly5.1 or LLO56-Thy1.1 mice were purified by negative selection and 3 × 10³ cells were transferred to C57BL/6 recipient mice. The mice were subsequently infected with 1 × 10⁴ CFU of L. monocytogenes and cell numbers were measured 7 d later by flow cytometery. (B) On day 35 after the primary infection recipient mice were infected with 1 × 10⁵ CFU of L. monocytogenes. Four days after the secondary infection cell numbers were determined by flow cytometry. Data are representative of three independent experiments with at least three mice per group each experiment. **P < 0.01 (Student t test).