The infection of SupT1 cells with pNL4–3 F2A-MHC-I-Flag Nef and subsequent Western blotting demonstrated that the presence of Nef does not alter the protein expression levels of MHC-I, confirming that Nef does not direct MHC-I to degradative lysosomal compartment, consistent with previous experiments (Fig. 5e)7, 22. Here, S100B is linked to infection.