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Abstract: A novel vaccine development platform that enables the site-specific conjugation of synthetic lipid adjuvants to recombinant proteins was produced. This technology facilitates the simple and efficient production of homogeneous, chemically-defined, semisynthetic lipoprotein vaccines. Using a polytope ‘string-of-beads’ approach, a synthetic gene incorporating seven Streptococcus pyogenes M protein strain-specific antigens, and a conserved M protein antigen (J14) was produced, expressed, and attached to a lipoamino acid based adjuvant (lipid core peptide; LCP). Nanoparticles (40nm diameter) of an optimal size for stimulating antibody-mediated immunity were formed upon the addition of these lipoproteins to aqueous buffer (PBS). Systemic antigen-specific IgG antibodies were raised against all eight antigens in C57BL/6J mice, without the need to formulate with additional adjuvant. These antibodies bound cell surface M proteins of S. pyogenes strains represented within the polytope sequence, with higher antibody levels observed where a dendritic cell targeting peptide (DCpep) was incorporated within the LCP adjuvant. From the Clinical Editor: In this study, a novel vaccine development system is presented, combining adjuvants with recombinant protein antigens, and presenting the antigen in a nanoparticle system optimized for antibody production. They demonstrate efficient vaccination in a murine model system without the need for additional adjuvants. [Copyright &y& Elsevier]

Abstract: The immunogenicity and protective efficacy in mice of intranasally (i.n.) administrated influenza subunit antigens together with lipid-based adjuvants (Eurocine®) were compared to those of subcutaneous (s.c.) immunisation. Influenza hemagglutination inhibition (HAI) and ELISA IgG titers were similar in the group''s vaccinated s.c. and after i.n. vaccination with adjuvants. The virus-specific IgA levels in serum were higher after vaccination i.n. with adjuvant than after s.c immunisation. Virus-specific IgA was measurable in nasal washings only after i.n vaccinations, with and without adjuvants. Thus, i.n. vaccination with the endogenous non-toxic, lipid adjuvants induced equal or stronger antibody responses as compared to s.c. immunisation with the same antigen. We further analysed the protective efficacy against virus challenge in a mouse model. A subunit antigen preparation of the A/New/Caledonia/20/99 strain was used for vaccination of NMRI mice with different combinations of adjuvants. The mice were challenged i.n. with 6.5 tissue culture infectious doses50 of homologous virus and sacrificed 3 days later. Since the virus is not lethal in mice, the protective efficacy was measured by quantitative, real-time PCR on pulmonary tissue, obtained at autopsy. The mice treated with only adjuvant and the group of naïve mice clearly had the highest mean viral RNA copy numbers (19.200 and 11.000, respectively). All vaccinated groups had significantly lower copy numbers, especially the mice that received the L3A i.n. (−median 120; i.n. L3B−median 2.200; and non-adjuvanted s.c. vaccination−median 2.600). Our findings prompt further investigations of the effect of the formulations in ferrets, monkeys and man. [Copyright &y& Elsevier]

The immunogenicity and protective efficacy of inactivated rotavirus vaccine administered intramuscularly with lipid adjuvants; MPL® (monophosphoryl lipid A from Salmonella minnesota) or L3® (monooleate/lauric acid) was evaluated in an infant mouse model. Purified and formalin-inactivated rhesus rotavirus (I-RRV) combined with one of the adjuvants were administered to female balb/c mice at 0, 4 and 8 weeks. High serum IgG antibody titers developed in all vaccinated groups; I-RRV (GMT 45,524±9,819), I-RRV-MPL® (GMT 190,637±64,250) and I-RRV-L3® (GMT 126,266±27,553). The formalin-inactivation procedure preserved neutralizing epitopes and elicited high neutralizing antibody titers; I-RRV (GMT 43,053 S.E.M.±4,189), I-RRV-MPL® (GMT 66,398 S.E.M.±20,202) and I-RRV-L3® (GMT 60,887 S.E.M.±10,750). All offsprings to immunized dams were protected against clinical diarrhea upon oral challenge with RRV. The IgG1/IgG2a ratio was in all immunized groups ∼1 suggesting development of a balanced Th1/Th2 response. [Copyright &y& Elsevier]

The radiation-resistant bacterium, Deinococcus radiodurans contains a variety of phospho-, glyco- and phosphoglycolipids, the structures of which appear to be largely unique in nature. We show here that such lipids are immunogenic when administered as liposomes intranasally in mice, as evidenced by the induction of serum antibodies which recognize D. radiodurans lipids but not other lipids by thin layer chromatographic immunostaining. By modifying a liposomal vaccine against respiratory syncytial virus (RSV) we find that vaccine efficacy is markedly enhanced by the inclusion of lipids isolated from D. radiodurans. Using dioleoylphosphatidylcholine (DOPC) or D. radiodurans lipids, liposomes were prepared which encapsulated a soluble fragment of the RSV G protein (G128–188) fused with a portion of the bacterial thioredoxin (Trx) protein. Mice immunized intranasally with D. radiodurans liposomes showed markedly greater protection against RSV challenge over mice immunized with DOPC liposomes. Enhanced vaccine efficacy was achieved using liposomes prepared from either whole D. radiodurans lipids or from a single isolated phosphoglycolipid previously identified as α-galactosylphosphatidylglyceroylalkylamine (lipid 7). Mice immunized and protected against RSV challenge were free of pulmonary eosinophilic infiltration, an undesirable consequence of many RSV vaccines. The results provide further support for liposome-based vaccines for RSV and underline the importance of lipid composition in liposome formulations. [Copyright &y& Elsevier]

A novel vaccine development platform that enables the site-specific conjugation of synthetic lipid adjuvants to recombinant proteins was produced. This technology facilitates the simple and efficient production of homogeneous, chemically-defined, semisynthetic lipoprotein vaccines. Using a polytope 'string-of-beads' approach, a synthetic gene incorporating seven Streptococcus pyogenes M protein strain-specific antigens, and a conserved M protein antigen (J14) was produced, expressed, and attached to a lipoamino acid based adjuvant (lipid core peptide; LCP). Nanoparticles (40 nm diameter) of an optimal size for stimulating antibody-mediated immunity were formed upon the addition of these lipoproteins to aqueous buffer (PBS). Systemic antigen-specific IgG antibodies were raised against all eight antigens in C57BL/6J mice, without the need to formulate with additional adjuvant. These antibodies bound cell surface M proteins of S. pyogenes strains represented within the polytope sequence, with higher antibody levels observed where a dendritic cell targeting peptide (DCpep) was incorporated within the LCP adjuvant., From the Clinical Editor: In this study, a novel vaccine development system is presented, combining adjuvants with recombinant protein antigens, and presenting the antigen in a nanoparticle system optimized for antibody production. They demonstrate efficient vaccination in a murine model system without the need for additional adjuvants., (Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.)