On the biochemical formation of the free Vi antigen, by the resting or acetone-killed typhoid organism.

Abstract

1) When the acetone killed cell suspension of Vi-O and Vi-R type typhoid bacilli was shaken with glucose and phosphate solution at 37'C, the cell free.Vi antigen was formed in the medium and this formation reached its maximum in 3 hours. 2) In spite of the repetition of the shaking incubations using the same cells, the Vi activity of the cells did not decrease. The cells metab-olized glucose and inorganic phosphorus accompanying Vi formation. 3) The O-antigen formation by means of the same method was titrated very faintly at the later stage of the incubation. It was revealed that glucose and phosphate did not participate to O-formation. 4) Cell quantities, the optimum concentration of sugar and the suitable kind of the sugars were investigated. 5) Glucosamine was the most active in the Vi formation. 6) The Vi-formation was inhibited perfectly by iodoacetate and this inhibition was recovered immediately by adding pyruvate.