Shigella flexneri 2a and sonnei I vaccine with two attenuating markers: construction, tolerability and immunogenicity in 143 children aged 3-17 years.

The vaccine candidates were constructed through stepwise incorporation of weakly attenuated purine auxotrophy with subsequent rifampicin resistance (RNA polymerase) mutation to yield optimal attenuation. These strains showed a maintained invasiveness for conjunctival epithelia. Therefore, while not causing keratoconjunctivitis, they were excreted for a short but marked period and provided partial protection in the Sereny test.

Live Shigella flexneri 2a and Shigella sonnei I vaccine candidate strains with two attenuating markers. II. Preliminary results of vaccination of adult volunteers and children aged 2-17 years.

Shigella flexneri 2a and Shigella sonnei I vaccine candidate strains were tested for tolerance in 14 adults as well as for tolerance and immunogenicity in children aged 2-17 years. For fresh culture material, the limit for side effects fading within 36 h such as meteorism, loose stools, tenesmus and slight temperature, and tolerated by volunteers was 3 x 10(9) colony-forming units (c.f.

Live Shigella flexneri 2a and Shigella sonnei I vaccine candidate strains with two attenuating markers. I. Construction of vaccine candidate strains with retained invasiveness but reduced intracellular multiplication.

Live Shigella flexneri 2a and Shigella sonnei Phase I vaccine candidate strains with two virulence-reducing markers were constructed through stepwise incorporation of weakly attenuating purine auxotrophy with subsequent rifampicin-resistance (RNA polymerase) mutation to yield optimal attenuation. These vaccine candidate strains showed an unaltered plasmid profile; did not cause keratoconjunctivitis in the Sereny test, while being excreted for a short but still marked period and providing partial protection from wild-strain infection; exhibited for guinea-pig conjunctival epithelia, HeLa cells and rat enterocytes a maintained invasiveness with reduced intracellular multiplication with little, if any, reversible cell damage; and produced, just as their ultrasonic lysates, no exudative reaction in the rabbit gut loop test.