The present invention relates to conjugates of oligosaccharides of formula 1, wherein R is a linker to a carrier protein and optionally comprises up to three further saccharides, 5 and which are useful for vaccination, methods of synthesis of such conjugates, antibodies against this antigen, hybridoma producing monoclonal antibodies against this antigen, assays using these antibodies for the detection of B. anthracis spores and kits comprising these antibodies, and a vaccine for the prevention of B. anthracis infection comprising the conjugates of oligosaccharides of formula 1. Monoclonal antibodies 10 according to the invention selectively bind to B. anthracis, but not to related bacteria such as B. subtilis, B. cereus and other bacteria of this group such as B. thuringiensis.