Attempts to Produce Immunity with Large Quantities of Killed Herpes Virus

Abstract

It has long been agreed and repeatedly stated that one of the principal differences between viruses and bacteria is the fact that apparently no immunity can be produced with a virus which is not living. So far there has not been a single acceptable experiment which would indicate that immunity may be produced with any virus which has been definitely destroyed by heat, chemicals, or any other means. That quite the opposite is true, with at least many bacterial forms, is well known. However, though the immunology of viruses has been studied a great deal, there have been no experiments reported, so far as we are aware, in which attempts to produce immunity with killed virus in very large quantities have definitely ruled out this possibility. It is obvious that if immunity with any virus depends upon quantity of the antigen employed and not upon the living nature of the virus much might be accomplished, with greater safety, by simply concentrating the virus for immunization purposes.

We have sought to test, by critical experiment, this possibility and have employed the L. F. strain of herpes virus for our experiments. Our herpes strain is one which one of us (E. B. McK.) brought to this country from Brussels, Belgium, in 1925, and for nearly 10 years it has been propagated in the brains of rabbits in this country. It regularly kills rabbits within 3 to 5 days when given in doses of 0.25 cc. of a 10% suspension of infected rabbit brain by the intraspinous route. For our experiment we selected 3 potent, whole, recently herpes-infected rabbit brains and emulsified these brains in 75 cc. of saline. The virus suspension was then heated at between 65 and 68.5°C. in a water bath for one hour.