1. Departamento de Inmunologı́ a, Instituto de Investigaciones Biomé dicas, UNAM, Apartado Postal 70228, 04510 México DF, Mexico1
2. GBF, German National Research Center for Biotechnology, 38124 Braunschweig, Germany2
3. Hospital General de México, SSA , Mexico3
4. MRC Tuberculosis and Related Infections Unit, Clinical Sciences Centre, Hammersmith Hospital, Du Cane Road, London, UK 4