Shanti Rywkin

Inactivation of viruses in blood with aluminum phthalocyanine derivatives

The inactivation of viruses added to whole blood and a red cell concentrate with aluminum phthalocyanine and its sulfonated derivatives was studied. A cell‐free form of vesicular stomatitis virus (VSV), used as a model, was completely inactivated (greater than 10(4) infectious units; TCID50) on treatment of whole blood with 10 microM (10 mumol/L) aluminum phthalocyanine chloride (AIPs) and visible light dosage of 88 to 176 J per cm2. At 44 J per cm2, complete VSV inactivation was achieved on raising the concentration of AIPc to 25 microM (25 mumol/L). Results at least as good were achieved on similar treatment of a red cell concentrate. Also inactivated were a cell‐associated form of VSV and both cell‐free and cell‐associated forms of human immunodeficiency virus; encephalomyocarditis virus, used as a model for non‐lipid‐enveloped viruses, was not inactivated by this procedure. This inactivation of cell‐free VSV suggests that a similar degree of inactivation could be achieved with a lower concentration of the sulfonated forms of aluminum phthalocyanine. Throughout the above studies, red cell integrity was well maintained, as judged by the absence of hemoglobin release (less than or equal to 2%) during the course of treatment or on subsequent storage. Red cell osmotic fragility was decreased on treatment of whole blood with AIPc. This study indicates that AIPc may be a promising method for the inactivation of viruses in cellular blood products.

IMPORTANCE OF TYPE I AND TYPE II MECHANISMS IN THE PHOTODYNAMIC INACTIVATION OF VIRUSES IN BLOOD WITH ALUMINUM PHTHALOCYANINE DERIVATIVES

The relative importance of type I and type II mechanisms in the photodynamic treatment of red blood cell concentrates (RBCC) to inactivate viruses was studied using aluminum phthalocyanine tetrasulfonate (AlPcS4), visible light and quenching or enhancing agents of reactive forms of oxygen. Treatment of a human RBCC with 10–13 μM AlPcS4 and 25–26 rnW/cm2 visible light resulted in the rapid and complete inactivation of added vesicular stomatitis virus (VSV). The addition of mannitol, glycerol, reduced glutathione (GSH), or superoxide dismutase (SOD), known quenching agents of type I mechanisms, had little to no effect on the rate of inactivation of VSV. Significant inhibition of VSV kill was observed on addition of tryptophan or sodium aide, known quenchers of type II mechanisms. Additionally, the rate of VSV kill was enhanced in the presence of D2O. Taken together, these results indicate a predominant role of singlet oxygen in the inactivation of VSV on photodynamic treatment of RBCC.

Virus inactivation in red cell concentrates by photosensitization with phthalocyanines : protection of red cells but not of vesicular stomatitis virus with a water-soluble analogue of vitamin E.

BACKGROUND: Photodynamic treatment of red cells (RBCs) with phthalocyanines and red light inactivates lipid‐enveloped viruses, such as vesicular stomatitis virus (VSV) and human immunodeficiency virus. To protect RBCs from photodynamic damage, type I free radical quenchers, such as mannitol, which did not affect virus inactivation, were added.