Leiden University Scholarly Publications

Enotarpi J., Tontini M., Balocchi C., Es D. van der, Auberger L., Balducci E., Carboni F., Proietti D., Casini D., Filippov D.V., Overkleeft H.S., Marel G.A. van der, Colombo C., Romano M.R., Berti F., Costantino P., Codeé J.D.C., Lay L., Adamo R. 2020

A stabilized glycomimetic conjugate vaccine inducing protective antibodies against Neisseria meningitidis serogroup A

Article / Letter to editor

open access

Neisseria meningitidis serogroup A capsular polysaccharide (MenA CPS) consists of (1 → 6)-2-acetamido-2-deoxy-α-D-mannopyranosyl phosphate repeating units, O-acetylated at position C3 or C4.... Show moreNeisseria meningitidis serogroup A capsular polysaccharide (MenA CPS) consists of (1 → 6)-2-acetamido-2-deoxy-α-D-mannopyranosyl phosphate repeating units, O-acetylated at position C3 or C4. Glycomimetics appear attractive to overcome the CPS intrinsic lability in physiological media, due to cleavage of the phosphodiester bridge, and to develop a stable vaccine with longer shelf life in liquid formulation. Here, we generate a series of non-acetylated carbaMenA oligomers which are proven more stable than the CPS. An octamer (DP8) inhibits the binding of a MenA specific bactericidal mAb and polyclonal serum to the CPS, and is selected for further in vivo testing. However, its CRM197 conjugate raises murine antibodies towards the non-acetylated CPS backbone, but not the natural acetylated form. Accordingly, random O-acetylation of the DP8 is performed, resulting in a structure (Ac-carbaMenA) showing improved inhibition of anti-MenA CPS antibody binding and, after conjugation to CRM197, eliciting anti-MenA protective murine antibodies, comparably to the vaccine benchmark. Show less