CANDIDATE LIVE ORAL CHOLERA VACCINE STRAINS PRODUCE A NEW CHOLERA-TOXIN

When six candidate live oral cholera vaccine strains deleted for one o r all known virulence factors are tested for enterotoxin production, t wo of them caused fluid accumulation in the initial rabbit ileal loop (RIL) test, the others did so after 1-3 serial passages through RIL, C ulture filtrates also showed similar secretory response. Ten times con centrated culture filtrates of these strains gave precipitin band agai nst anti-new cholera toxin showing reaction of identity. These observa tions clearly indicate that vaccine strains produce a secretogen antig enically similar to the new cholera toxin.