CD4 and infection: Trafficking and maturation of phagosomes in which pathogenic mycobacteria reside is manipulated to prevent lysosomal killing and degradation.20 Surprisingly, in spite of overwhelming infection, macrophages and DCs in the early granuloma are inefficient in presenting M. tuberculosis antigens in the early granuloma to CD4+ T-cells.21 Efficient MTB Antigen (Ag)-presentation only takes place later in the lymphnode.22 Mycobacteria, as exemplified by the zebrafish-M.