TARGET STRUCTURES FOR HIV-1 INACTIVATION BY METHYLENE-BLUE AND LIGHT

In a photodynamic virus inactivation procedure for human fresh frozen plasma the plasma is exposed to visible light in the presence of 1 mu M methylene blue. This procedure is known to inactivate HIV-1 by at le ast 10(6.32) TCID50/ml within 10 minutes. To elucidate the mechanism o f photodynamic inactivation of HIV-1 by methylene blue/light treatment , reverse transcriptase (RT), the HIV-1 associated protein p24, and vi ral RNA were examined. In the dark, methylene blue up to 10 mu M has n o inhibitory effect on recombinant RT. In the presence of light, recom binant RT inactivation was dependent on illumination time and the conc entration of methylene blue. After photoinactivation of the whole viru s by methylene blue/light treatment, RT activity was also almost compl etely inhibited. Simultaneously, it was found by Western blotting that HIV-1 p24 and gp120 are altered in size, possibly due to protein cros s-linking. In addition, it was shown by polymerase chain reaction (PCR ) inhibition assay that HIV-1 inactivation leads to destruction of its RNA. In summary, methylene blue/light treatment acts on HIV-1 at diff erent target sites: the envelope and core proteins, and the inner core structures RNA and RT. (C) 1995 Wiley-Liss, Inc.