Amplification of superoxide anion generation in phagocytic cells by HIV-1 infection.

Amplification of superoxide (O2-) generation by HIV-1 infection was examined in two human myeloid-monocytic cell lines. The level of O2- generation in HL-60 after infection became significantly higher than that of the steady-state. A similar phenomenon was also shown in U937, but only after acquisition of O2- generation ability by differentiation to macrophages. By means of the NADPH oxidase-coupled responses in infected cells, we reconstituted the O2(-)-generating machinery in cell-free system. The results suggested that cytosolic factor(s) exerted by infection might be responsible for the amplification of O2- generation. Thus, HIV-1 infection could elevate the level of oxidative stress in macrophages which might play an important role in disease progression.