[Photodynamic inactivation of model virus in human plasma by methylene blue and its influence on plasma proteins].

OBJECTIVE

To determine whether photochemical method can inactivate viruses in human plasma efficiently, and to what extent it affects the protein in human plasma.

METHODS

Vascular stomatitis virus (VSV) Indiana strain was used as the indicating virus. It was inoculated on Vero cell monolayer, incubated in 37 degrees C for 24 hours, microtitered by cytopathogenic effect. Small amount experiments were carried out to observe virus inactivation and the influence on plasma proteins.

RESULTS

Methylene blue (MB) in combination with visible light can inactivate the model virus in human plasma efficiently. The dye in very low concentration combined with light was sufficient to achieve a reduction of VSV titer of more than 6 log10 TCID50. Compared with the untreated plasma, neither the activities of blood clotting factors nor the immunological properties of the plasma proteins and the blood albumin were reduced significantly. In this experiment, the dose of MB used for photoinactivation of the virus was very low, about a hundred fold lower than that of methemoglobinemia used in clinical treatment. Furthermore, heat of the light and photochemical reaction are two import factors for decreasing of clotting factor's activity.

CONCLUSIONS

The results of this preliminary study suggest the potential application of MB-photodynamic inactivation of plasma virus is an useful approach in clinical practice.