IL-12 (p70) production by M. avium-infected MDM cocultured with CD40L-293 cells. M. avium-infected MDM and uninfected MDM were cultured with medium alone, pcDNA-293 cells, or CD40L-293 cells. On days 1, 3, and 7 after infection, culture supernatants were collected and assayed for IL-12 (p70) by ELISA. Experiments were done in triplicate, and results are expressed as mean ± SD. ∗, P < 0.03 compared to M. avium-infected MDM cultured with pcDNA-293 cells.