Novel Synthetic (Poly)Glycerolphosphate-Based Antistaphylococcal Conjugate Vaccine

Abstract

g Staphylococcal infections are a major source of global morbidity and mortality. Currently there exists no antistaphylococcal vaccine in clinical use. Previous animal studies suggested a possible role for purified lipoteichoic acid as a vaccine target for eliciting protective IgG to several Gram-positive pathogens. Since the highly conserved (poly)glycerolphosphate backbone of lipoteichoic acid is a major antigenic target of the humoral immune system during staphylococcal infections, we developed a synthetic method for producing glycerol phosphoramidites to create a covalent 10-mer of (poly)glycerolphosphate for potential use in a conjugate vaccine. We initially demonstrated that intact Staphylococcus aureus elicits murine CD4؉ T cell-dependent (poly)glycerolphosphate-specific IgM and IgG responses in vivo. Naive mice immunized with a covalent conjugate of (poly)glycerolphosphate and tetanus toxoid in alum plus CpG-oligodeoxynucleotides produced high secondary titers of serum (poly)glycerolphosphate-specific IgG. Sera from immunized mice enhanced opsonophagocytic killing of live Staphylococcus aureus in vitro. Mice actively immunized with the (poly)glycerolphosphate conjugate vaccine showed rapid clearance of staphylococcal bacteremia in vivo relative to mice similarly immunized with an irrelevant conjugate vaccine. In contrast to purified, natural lipoteichoic acid, the (poly)glycerolphosphate conjugate vaccine itself exhibited no detectable inflammatory activity. These data suggest that a synthetic (poly)glycerolphosphate-based conjugate vaccine will contribute to active protection against extracellular Gram-positive pathogens expressing this highly conserved backbone structure in their membrane-associated lipoteichoic acid.

Lipoteichoic Acid Synthesis and Function in Gram-Positive Bacteria

“…To increase the immunogenicity of LTAs, the production of conjugate vaccines is currently being pursued. Recent studies have reported on the synthesis of a conjugate between synthetic type I LTA and the immunogenic tetanus toxin protein or between type V LTA of C. difficile with E. coli enterotoxin or a Pseudomonas exotoxin (13,18,25). Much effort has gone into the use of type I LTA-specific antibodies in passive immunization studies (118,129,130).…”

Teichoic acids: synthesis and applications

“…58 They applied a synthetic strategy that involves benzoyl protected glycerol phosphoramidite 153 (Scheme 13). 58 They applied a synthetic strategy that involves benzoyl protected glycerol phosphoramidite 153 (Scheme 13).…”

Synthesis of E. faecium wall teichoic acid fragments

“…To a cooled (-40°C) solution of 13 (0.17 g, 0.5 mmol) in dry DMF (2 ml 4, 134.0, 129.2, 128.4, 127.9, 85.4, 72.3, 71.8, 69.8, 66.7, 62.1, 27.6, 27.3 2, 134.5, 133.4, 133.2, 129.4, 129.2, 128.6, 128.5, 128.3, 128.0, 127.9, 127.8, 126.7, 126.4, 126.3, 126.1, 125.9, 125.6, 85.9, 78.8, 71.0, 70.5, 70.3, 67.0, 59.8, 28.0, 27.4 4, 133.3, 133.2, 133.1, 129.3, 128.7, 128.2, 128.1, 127.9, 127.1, 126.5, 126.5, 125.7, 84.7, 78.8, 72.3, 72.2, 67.2, 62.8, 60.3 3,137.9,135.0,134.8,133.4,133.2,129.1,128.5,128.4,128.1,127.9,127.8,127.7,126.6,126.3,126.2,125.7,85.5,80.3,75.0,73.5,73.2,72.5,72.0,68.4,61.2;HRMS: [C 37 138.0,137.9,137.4,137.1,135.0,134.9,133.2,133.1,132.9,128.3,128.2,128.1,128.0,127.9,127.8,127.7,127.,127.3,126.8,126.4,126.3,…”

“…Novel ways to combat these bacteria are urgently needed and therefore different vaccination strategies are currently being developed. 3,4 Teichoic acids (TAs), polyalditol phosphate based glycopolymers, are major components of the cell wall of Grampositive bacteria, accounting for up to 70% of the dry weight of the bacterial cell wall. Two types of TAs are commonly present in the Gram-positive cell wall.…”