PHOTOSENSITIZED DECONTAMINATION OF BLOOD WITH THE SILICON PHTHALOCYANINE PC-4 - NO ACTIVATION OF THE HUMAN-IMMUNODEFICIENCY-VIRUS PROMOTER

Photochemical decontamination of red blood cell concentrates (RBCC) wi th the silicon phthalocyanine Pc4 and red light is being studied to en hance the viral safety of blood transfusion. Recent reports indicate t hat treatments with radiation and various phototsensitizing agents can activate the promoter of human immunodeficiency virus (HIV). This rai ses the possibility that an inadequate, sublethal photochemical treatm ent of RBCC could induce HIV in latently infected cells, This question has been addressed using HeLa cells stably transfected with the chlor amphenicol acetyl transferase gene under the control of the HIV promot er. In control studies, 8-methoxypsoralen (8-MOP) excited by UVA light caused activation of the HIV promoter in a dose- and time-dependent m anner. At 0.1 mu g/mL of 8-MOP, maximal activation occurred with 18 J/ cm(2), 30 h after light exposure. With Pc 4 at 20 nM, over 90% of HeLa cells were killed after 24 h when exposed to 1 J/cm(2) of red light. During that time interval and over a wide range of light doses no acti vation of the HIV promoter occurred. It is concluded that RBCC sterili zation with Pc 4 and red light is unlikely to induce HIV production in latently infected cells.