FIG. 7.

MHC class I presentation of SIINFEKL is not inhibited by lactacystin and is partly TAP independent in BMDC and splenic dendritic cells. We treated 10⁵ BMDC for 3 h with 10 μM lactacystin or left them untreated and then infected them in 96-well plates with M. bovis BCG-OVApet at a multiplicity of infection of 1, 10, 50, or 100 for 2 h at 37°C or pulsed them with SIINFEKL peptide. The remaining extracellular bacteria were killed by a 2-h treatment with 200 μg of amikacin per ml at 37°C. Dendritic cells were then washed in PBS and cocultured with 10⁵ B3Z cells for 16 h at 37°C. Supernatants were assayed for IL-2 by solid-phase ELISA (A). We infected 10⁵ BMDC (B and C) or splenic dendritic cells (D) from C57BL/6 or TAP1^−/− mice with M. bovis BCG-OVApet or pulsed them with SIINFEKL peptide, and presentation of SIINFEKL to B3Z cells was determined as described above. A statistically significant decrease or increase in presentation following lactacystin treatment or the use of TAP1^−/− dendritic cells is indicated by * (P < 0.05, Student t test).