The cell pellets were harvested, lysed, protein levels quantified (12.5 μg loaded per lane) and analyzed, using Western blot, for the presence of markers of cell death (i.e., Poly [ADP-ribose] polymerase 1 (PARP-1) and Bcl-2-associated X protein (Bax)) that would suggest decreased cell viability, and virus (i.e., Nef) to validate for productive viral infection. Here, S100B is linked to viral infectious disease.