Cultivation of Herpes Virus,and Use of the Mouse in its Titration

Abstract

Parker and Nye 1 attempted, unsuccessfully, to cultivate the herpes virus. Rivers 2 and his coworkers, using rabbit cornea embedded in rabbit plasma, were, however, more successful, and later, Gildemeis-ter 3 and his associates grew 7 the virus over 22 successive generations, their medium being rabbit testicle in rabbit plasma. The most recently published work in this connection has been that of An-drewes, 4 who reported successful cultivation of the herpes virus over 23 successive generations.

We have recently successfully cultivated the H. F. strain of herpes virus through 25 generations. The medium used has been similar to that of Andrewes. Three cc. of Tyrode's solution and 1 cc. of normal rabbit serum were placed in small River's flasks, to which were added fragments of finely minced fresh rabbit testicle. The original inoculum was 0.2 cc. of a 10% emulsion of brain from a rabbit which had succumbed to typical herpetic encephalitis. In making subsequent transfers from one generation to another, 0.2 cc. of the preceding culture was inoculated into freshly prepared flasks. These flasks were incubated for 4 days.

In testing for the presence of virus, corneal inoculations were used. Inasmuch as it is desirable to have confirmation of growth other than extended numbers of passages, it was deemed pertinent to attempt the use of mice as a means of titration. The susceptibility of mice has, of course, been known for some time. Blanc and Caminopetros, 5 Doerr and Schnabel, 6 and Flexner and Amoss 7 first showed that a fatal encephalitis in mice followed appropriate intracranial inoculations. The most recently reported work with mice has been that of Andervont. 8 , 9

Preliminary experiments with our cultures revealed that the cultivated virus produced an encephalitis in mice in dilutions up to 1:500.