Bacteriophages may be useful as surrogates for animal viruses when the virucidal properties of different photosensitizing compounds are initially investigated. We studied photoinactivation of four bacteriophages, phi X174, T7, PRD1, and phi 6, by the dye merocyanine 540 (MC540) (15 micrograms/mL). Merocyanine 540 (MC540) should be most effective with lipid-containing viruses, since it is primarily lipophilic (but also binds to proteins). Two of the phages, PRD1 and phi 6 contain lipid, with only phi 6 having an external lipoprotein envelope. Filtered radiation (450-600 nm) from a 750 W projector was used at 16-100 W/m2. The survival curves of the different viruses clearly demonstrated different levels of sensitivity to photoinactivation by MC540, with phi 6 (Do = 1.5 kJ/m2) being the most sensitive, followed by T7 (21-fold less sensitive). While both PRD1 and phi 6 have lipid components, only phi 6 was photoinactivated by MC540. Thus the internal lipid components of PRD1 were not sufficient to allow photoinactivation by this dye, at fluences up to 300 kJ/m2. For comparison, we also photoinactivated Herpes simplex virus (Do = 0.053 kJ/m2) and found it to be 28-fold more sensitive than phi 6 to photoinactivation by the same concentration of MC540. Thus phi 6 may be used as a surrogate for enveloped human viruses for photoinactivation by lipophilic dyes, but the results may only be useful qualitatively.

This study evaluated bacteriophages 1)X174, T7, PRD1, and 4)6 as possible surrogates for pathogenic human viruses to challenge barrier materials and demonstrated some important factors for their use. Chemical incompatibility with test material was demonstrated when lipid-enveloped 1)6 was inactivated by an aqueous eluate of vinyl gloves, but 0.5% calf serum protected (D6 from the eluate. Low concentrations (2%) of calf serum also prevented the exaggerated binding of the bacteriophages to filters. Recovery of viruses from surfaces decreased with increasing time before recovery. Penetration through punctures displayed different types of kinetics. The combined data indicate that (i) some bacteriophages may serve as surrogate viruses, (ii) experimental conditions determine whether a particular virus is appropriate as a challenge, and (iii) 1)X174 is an excellent choice as a surrogate virus to test barrier materials. The data further indicate that before barrier materials are challenged with viruses, adequate tests should be performed to ensure that the virus is compatible with the test material and test conditions, so that meaningful data will result.

Filters with well-defined holes were used to determine the effective diameters in buffer of human inmunodeficiency virus type 1, herpes simplex virus type 1, and four bacteriophages (+X174, T7, PRD1, and +6), which may serve as surrogate viruses for testing barrier materials. Bacteriophages +6 and PRD1 most closely model human immunodeficiency virus type 1 in filtration size.

The effect of the photosensitizer merocyanine 540 (MC 540) on platelets and on three marker viruses was examined to assess its potential in reducing virus transmission by blood products. The results demonstrated several deleterious effects of MC 540 (4-24 micrograms/mL) on platelet morphology and function in both the absence and presence of light (450-600 nm). Treatment of washed platelets with MC 540 in the dark resulted in a significant release of serotonin in the absence of added agonist, as well as a diminished response to thrombin as measured in vitro. In addition, photosensitization caused spontaneous platelet aggregation and release of 92 percent of the releasable serotonin without the addition of an agonist. Because photo-treatment of blood products is likely to be performed in a protein-rich medium, the influence of albumin on the phototoxic effects on platelets was assessed. Albumin added to the suspension medium at concentrations greater than or equal to 1.0 percent protected the platelets against the effects of MC 540 in the dark, whereas 5-percent albumin was required for protection against the phototoxic effects of MC 540 on the platelet response to thrombin. The antiviral activity of MC 540 and light was examined by using the lipid-containing viruses herpes simplex virus (HSV) and bacteriophages phi 6 and PM2. Of the lipid-enveloped viruses, HSV was 25 times more photosensitive to MC 540 than was phi 6 (15 micrograms/mL). PM2, which has an internal lipid layer, was almost 300 times less sensitive to MC 540 and light than was HSV.(ABSTRACT TRUNCATED AT 250 WORDS)

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