Thermostability and Alcohol Solubility of Vi Antigen

Abstract

The present investigation was suggested by an unpublished observation made by one of us several years ago while working on Vi antigens and antibodies. An antiserum prepared against a motile Vi positive typhoid strain, H-484, was adsorbed 3 times with Salmonella ballerup. No drop in titer occurred for either O-901, H-484 or its nonmotile Vi positive variant, O-484. However, a marked prozone, increasing with the number of adsorptions, developed against 0-484 (Table I). When S. ballerup was washed in several changes of saline before being used for adsorption, the prozone against 0-484 failed to appear. It would seem that the Vi antigen was related to this prozone since it was the only component common to 0-484 and S. ballerup. The present work is an attempt to explain this reaction.The growth of S. ballerup was removed from plates using 5 ml of saline for every 2 plates. The mixture was shaken several times, centrifuged after 30 minutes and the supernatant fluid used to harvest more plates. The procedure was...