β-1,2-Oligomannan phosphorylase-mediated synthesis of potential oligosaccharide vaccine candidates.

β-(1,2)-Mannan antigens incorporated into vaccines candidates for immunization studies, showed that antibodies raised against β-(1,2)-mannotriose antigens can protect against disseminated candidiasis. Until recently, β-(1,2)- mannans could only be obtained by isolation from microbial cultures, or by lengthy synthetic strategies involving protecting group manipulation. The discovery of two β-(1,2)-mannoside phosphorylases, Teth514_1788 and Teth514_1789, allowed efficient access to these compounds. In this work, Teth514_1788 was utilised to generate β-(1,2)-mannan antigens, tri- and tetra-saccharides, decorated with a conjugation tether at the reducing end, suitable to be incorporated on a carrier en-route to novel vaccine candidates, illustrated here by conjugation of the trisaccharide to BSA.