Safety and antigenicity of typhoid-Shigella sonnei vaccine (strain 5076-1C).

The form-1 antigen of Shigella sonnei was transferred to the avirulent Salmonella typhi strain 21a and the resulting 5076-1C transconjugate strain was tested for safety and immunogenicity as a candidate oral vaccine. The transconjugant strain was shown to be well tolerated and safe in 19 human volunteers who were fed from 1 X 10(7) to 1 X 10(10) organisms. Only two of 10 volunteers tested had developed a rise in antibody titer to the lipopolysaccharide of the hybrid 5076-1C strain.