Abstract
We discovered that some S. typhi (V type) produced strong soluble protective antigen (SPA) that did not contain any toxity in TSA media.
It is not O-antigen because it is not produced from W-type and Schwartzman reaction is negative; moreover it is not assumed to be Vi-antigen or heat-labil-protective antigen as Jenkins, because it is not produced from B. Ballerup containing Vi-antigen in common with S. typhi.
We assume it to be a kind of soluble antigen of a new type, different from the well-known somaticprotective-antigen.
