Viruses Inactivated by Mustard (Bis(β-chloroethyl) Sulfide) as Vaccines

Abstract

For some years we have been using the rapidly advancing knowledge of protein chemistry in an attempt to find an agent other than formaldehyde that would inactivate viruses without destroying their anti-genic nature. Formaldehyde reacts primarily with amino groups of protein but it also attacks other radicals. While some formal-inized virus preparations are good immunizing agents many are not satisfactory, perhaps because the virus is not present in sufficient quantity. Reagents known to react with amino, tyrosine phenol, or SH groups of protein and several detergents have been used with disappointing results. Either the virus was not completely inactivated or else it failed to immunize animals to the active virus. It has been shown that mustard (Cl— CH₂—CH₂)₂—S reacts with proteins 1 and it is our purpose here to report the tests we have made on the effect of this chemical on a number of viruses.

Eastern equine encephalomyelitis virus, fixed rabies virus, and hog cholera virus have been treated with chemically pure mustard.

For most of our experiments virus-containing suspensions were twice saturated, but in some instances they were half saturated by railing an equalquantity of freshly saturated and centrifuged cold salt solution with the virus material. Care was taken to keep the reaction of the materials between pH 7 and 8 and at 25°C. Contrary to our previous results nith otherchemical reagents. We have had no difficulty in completely inactivating these viruses and all of the inactive preparations have had some immunizingability.