The present invention relates to compounds derived from sugars which reproduce the epitopes of Shigella flexneri serotypes 3a and X and to the use thereof for the preparation of vaccine compositions. More specifically, the subject matter of the present invention relates to novel glycoconjugated compounds comprising oligosaccharides or polysaccharides described hereinafter, to the method for synthesizing these oligosaccharides or polysaccharides and glycoconjugates, to derivatives of these oligosaccharides or polysaccharides, to compositions containing same, and also to the use of the glycoconjugates for vaccination purposes. Finally, the present invention relates to methods for diagnosing a Shigella flexneri infection using one or more oligosaccharides or polysaccharides or conjugates thereof.
