A semisynthetic carbohydrate-lipid vaccine that protects against S. pneumoniae in mice.

Severe forms of pneumococcal meningitis, bacteraemia and pneumonia result in more than 1 million deaths each year despite the widespread introduction of carbohydrate-protein conjugate vaccines against Streptococcus pneumoniae. Here we describe a new and highly efficient antipneumococcal vaccine design based on synthetic conjugation of S. pneumoniae capsule polysaccharides to the potent lipid antigen α-galactosylceramide, which stimulates invariant natural killer T (iNKT) cells when presented by the nonpolymorphic antigen-presenting molecule CD1d. Mice injected with the new lipid-carbohydrate conjugate vaccine produced high-affinity IgG antibodies specific for pneumococcal polysaccharides. Vaccination stimulated germinal center formation; accumulation of iNKT cells with a T follicular helper cell phenotype; and increased frequency of carbohydrate-specific, long-lived memory B cells and plasmablasts. This new lipid-carbohydrate vaccination strategy induced potent antipolysaccharide immunity that protected against pneumococcal disease in mice and may also prove effective for the design of carbohydrate-based vaccines against other major bacterial pathogens.

Probing cell-surface carbohydrate binding proteins with dual-modal glycan-conjugated nanoparticles.

Dual-modal fluorescent magnetic glyconanoparticles have been prepared and shown to be powerful in probing lectins displayed on pathogenic and mammalian cell surfaces. Blood group H1- and Le(b)-conjugated nanoparticles were found to bind to BabA displaying Helicobacter pylori, and Le(a)- and Le(b)-modified nanoparticles are both recognized by and internalized into DC-SIGN and SIGN-R1 expressing mammalian cells via lectin-mediated endocytosis. In addition, glyconanoparticles block adhesion of H. pylori to mammalian cells, suggesting that they can serve as inhibitors of infection of host cells by this pathogen. It has been also shown that owing to their magnetic properties, glyconanoparticles are useful tools to enrich lectin expressing cells. The combined results indicate that dual-modal glyconanoparticles are biocompatible and that they can be employed in lectin-associated biological studies and biomedical applications.

3-Allyl-2-hydr-oxy-5,6,8-trimethoxy-naphthalene-1,4-dione.

In the crystal structure of the title compound, C(16)H(16)O(6), a pair of naphthoquinone rings are linked via O-H⋯O-C hydrogen bonds in a nearly orthogonal arrangement. This dimeric unit is linked to a neighbouring dimer by π-π stacking inter-actions between the naphthoquinone rings, where the distance between the mean plane of the naphtoquinone backbones is 3.468 Å, and O-H⋯O-C hydrogen bonds.

Synthesis, Liposomal Formulation, and Immunological Evaluation of a Minimalistic Carbohydrate-α-GalCer Vaccine Candidate.

Fully synthetic glycan-based vaccines hold great potential as preventive and therapeutic vaccines against infectious diseases as well as cancer. Here, we present a two-component platform based on the facile conjugation of carbohydrate antigens to α-galactosylceramide (α-GalCer) to yield fully synthetic vaccine candidates. Formulation of the cancer-associated Tn antigen glycolipid model vaccine candidate into liposomes of different sizes and subsequent immunization of mice generated specific, high-affinity antibodies against the carbohydrate antigen with characteristics of T cell-dependent immunity. Liposome formulation elicited more reproducible glycan immunity than a conventional glycoconjugate vaccine bearing the same glycan antigen did. Further evaluation of the immune response revealed that the size of the liposomes influenced the glycan antibody responses toward either a cellular (Th1) or a humoral (Th2) immune phenotype. The glycolipid vaccine platform affords strong and robust antiglycan antibody responses in vivo without the need for an external adjuvant.