Related Experiment Videos
Differential inactivation of surrogate viruses with merocyanine 540
C D Lytle1, A P Budacz, E Keville
1Center for Devices and Radiological Health, FDA, Rockville, MD 20857.
Abstract:
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.
Insights
Bacteriophages like phi 6 can serve as surrogates for enveloped viruses in studies of photoinactivation. Merocyanine 540 (MC540) dye effectively inactivates enveloped viruses, but not those with internal lipids.
Area of Science:
- Virology
- Photochemistry
- Antiviral research
Background:
- Bacteriophages are viruses that infect bacteria and can be used as models for animal viruses.
- Photosensitizing compounds, like merocyanine 540 (MC540), are investigated for their virucidal properties.
- Lipophilic dyes like MC540 are expected to be more effective against lipid-containing viruses.
Purpose of the Study:
- To evaluate the effectiveness of merocyanine 540 (MC540) in photoinactivating different bacteriophages.
- To determine if bacteriophages can serve as surrogates for enveloped animal viruses in photoinactivation studies.
- To assess the relationship between viral lipid content and susceptibility to MC540-mediated photoinactivation.
Main Methods:
- Four bacteriophages (phi X174, T7, PRD1, phi 6) were exposed to merocyanine 540 (MC540) and filtered light (450-600 nm).
- Viral survival curves were analyzed to determine sensitivity to photoinactivation.
- Herpes simplex virus was used as a reference for comparison.
Main Results:
- Bacteriophage phi 6, with an external lipoprotein envelope, was the most sensitive to MC540 photoinactivation (Do = 1.5 kJ/m2).
- Bacteriophage T7 showed significantly lower sensitivity, being 21-fold less sensitive than phi 6.
- PRD1, despite having internal lipids, was not photoinactivated by MC540, indicating external lipid envelopes are crucial.
- Herpes simplex virus was 28-fold more sensitive than phi 6.
Conclusions:
- Bacteriophage phi 6 can serve as a qualitative surrogate for enveloped human viruses in photoinactivation studies using lipophilic dyes like MC540.
- The presence of an external lipoprotein envelope is critical for effective photoinactivation by MC540.
- Internal lipid components alone do not confer susceptibility to MC540-mediated photoinactivation.