Photodynamic Action of Methylene Blue on Poliomyelitis Virus. ∗

Abstract

Reitz 1 reviewed the effects of the combined action of light and dyes on a number of bacteria, and found that methylene blue, among other dyes, was a very active photodynamic agent. More recently, Tung 2 has also studied the photodynamic effect of methylene blue on a number of microörganisms. Perdrau and Todd 4 have reported on the photodynamic effect of methylene blue on a number of viruses including vaccinia, herpes, and canine distemper. Their method consisted of exposing dilute mixtures of methylene blue and the virus filtrate to the radiation of a 100 c.p. pointolite light, at a distance of 20 cm. from the petri dishes which contained the mixtures in 2 mm. layers. The final methylene blue concentrations used varied from 1:10,000 to 1:100,000 and the exposure times ranged from 5 to 30 minutes. After irradiation, the infectivity of the mixtures was tested in animals. Their results indicated that most of the viruses studied were completely inactivated by the above treatment. Perdrau and Todd 4 furthermore observed that although the virus of canine distemper was inactivated, it remained antigenic, and animals treated with this inactivated virus did not develop signs of the disease but showed considerable resistance to infections with the active virus. Shortt and Brooks, 5 however, could not demonstrate any immunity produced by inoculating animals with photodynamically inactivated rabies virus.

This report deals with the photodynamic action of methylene blue on the virus of poliomyelitis.

The methods employed were essentially those of Perdrau and Todd. 3 , 4 The methylene blue was Grubler's Methlenbalu, f. Bac. Koch, which was autoclaved when made up to twice the required dilution with saline (See Table I). To insure uniformity only small amounts were made up at frequent intervals.