HYPERICIN AS AN INACTIVATOR OF INFECTIOUS VIRUSES IN BLOOD COMPONENTS

Background: Hypericin is a potent virucidal agent with activity agains t a broad range of enveloped viruses and retroviruses. The effective v irucidal activity emanates from a combination of photodynamic and lipo philic properties. Hypericin binds cell membranes (and, by inference, virus membranes) and crosslinks virus capsid proteins. This action res ults in a loss of infectivity and an inability to retrieve the reverse transcriptase enzymatic activity from the virion. Study Design and Me thods: Since hypericin is devoid of adverse action in most blood compo nents and blood analyses, it is investigated as an additive with poten tial to inactivate infective viruses in blood components intended for transfusion. Results: Complete inactivation of 10(6) tissue culture-in fective doses of human immunodeficiency virus was obtained in whole bl ood and in diluted packed red cells after illumination with fluorescen t light for 1 hour, Loss of viral infectivity to cultured CEM cells ha s been monitored by use of a detection assay for human immunodeficienc y virus p55 in enzyme-linked immunosorbent assay and cytopathic assays . In physiologic media, hypericin interacts with albumin and lipoprote ins, retaining the virucidal activity in bound form. The molecule is n egatively charged and forms organic and inorganic monobasic salts (ion pairs) in physiologic pH, Various ion pairs differ in virucidal effic acy. Conclusion: The apparent transfusibility of hypericin, taken toge ther with the efficacy of the virucidal activity, the broad range of e nveloped viruses affected, and the absence of adverse effects on store d red cells, may render hypericin useful for inactivation of infectiou s viruses in red cells.