Article

Guy, B. The perfect mix: recent progress in adjuvant research. Nat Rev Microbiol 5: 505-517

Research Department, sanofi pasteur, Campus Merieux, 69280 Marcy l'Etoile, France.
Nature Reviews Microbiology (Impact Factor: 23.57). 08/2007; 5(7):505-17. DOI: 10.1038/nrmicro1681
Source: PubMed

ABSTRACT

Developing efficient and safe adjuvants for use in human vaccines remains both a challenge and a necessity. Past approaches have been largely empirical and generally used a single type of adjuvant, such as aluminium salts or emulsions. However, new vaccine targets often require the induction of well-defined cell-mediated responses in addition to antibodies, and thus new immunostimulants are required. Recent advances in basic immunology have elucidated how early innate immune signals can shape subsequent adaptive responses and this, coupled with improvements in biochemical techniques, has led to the design and development of more specific and focused adjuvants. In this Review, I discuss the research that has made it possible for vaccinologists to now be able to choose between a large panel of adjuvants, which potentially can act synergistically, and combine them in formulations that are specifically adapted to each target and to the relevant correlate(s) of protection.

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Available from: Bruno Guy, Jul 30, 2014
    • "Some authors divided the adjuvants into two groups: immunostimulants (adjuvants that interact with specific receptors of antigen presenting cells) and delivery systems [4]. Particulate delivery systems may act as adjuvants because they can modify the uptake, trafficking and processing of antigens, which results in better and more adequate immune responses [5] [6]. "
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    ABSTRACT: The use of biodegradable nanoparticles as antigen delivery vehicles is an attractive approach to overcome the problems associated with the use of Alum-based classical adjuvants. Herein we report, the design and development of protamine-based nanoparticles as novel antigen delivery systems, using recombinant hepatitis B surface antigen as a model viral antigen. The nanoparticles, composed of protamine and a polysaccharide (hyaluronic acid or alginate), were obtained using a mild ionic cross-linking technique. The size and surface charge of the nanoparticles could be modulated by adjusting the ratio of the components. Prototypes with optimal physicochemical characteristics and satisfactory colloidal stability were selected for the assessment of their antigen loading capacity, antigen stability during storage and in vitro and in vivo proof-of-concept studies. In vitro studies showed that antigen-loaded nanoparticles induced the secretion of cytokines by macrophages more efficiently than the antigen in solution, thus indicating a potential adjuvant effect of the nanoparticles. Finally, in vivo studies showed the capacity of these systems to trigger efficient immune responses against the hepatitis B antigen following intramuscular administration, suggesting the potential interest of protamine-polysaccharide nanoparticles as antigen delivery systems.
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    • "Adults worms of F. hepatica adult worm secrete a variety of molecules that direct the immune response towards a favourable non-protective Th2-mediate/regulatory environment, like the excretory secretory antigens of F. hepatica which have been widely studied by Dalton et al. (2013). Adjuvants can influence the T-helper cell polarisation creating bias towards Th1 or Th2 immune responses (Guy 2007), but some adjuvant substances have toxic or undesirable side effects. Hence, seeking for non-toxic adjuvants is an important task. "
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    ABSTRACT: We have studied the influence of both levamisole (AL) and Freund's adjuvant (AF) on the immunisation of mice with the secretory antigens of adults of the liver fluke Fasciola hepatica Linnaeus, 1758. Total IgG antibodies were detected in all groups where the F. hepatica antigen was administered, been levels of IgG1 increased respect to IgG2a antibodies. During immunisation, IL-4 and IFN-γ were only detected in AL and AF groups, but after infection, IL-4 boosted in all groups. IFN-γ increased two fold in AF and AL groups compared to the saline solution (AS) group. Worm recovering was of 32-35% in groups administered without antigen whereas in AS, AL and AF groups recovering was of 25%, 12% and 8%, respectively. Macroscopical lesions in the liver were scarce in AL and AF groups. Our data suggest that immunisation of mice with antigens of F. hepatica enhances the immune response avoiding both liver damage and worm establishment after challenge infection. The murine model of fasciolosis has appeared to be useful to elucidate the mechanism by which the parasite modulates immune responses toward a Th2 type but also the development of Th1 type-inducing vaccines.
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    • "New adjuvants based on nanospheres, microspheres or microparticles have been developed, and some have induced a good immune response with less damage than associated with oil-based adjuvants [6e9]. Some oil-based adjuvants, such as those formed by Freund's adjuvant , Montanide ISA51 or ISA720, are used to form water-in-oil emulsions in which aqueous droplets containing the antigen are dispersed in the oily phase [10]. These droplets are of different sizes, and the larger ones cannot be phagocytosed and transported from the peritoneal cavity to lymphoid organs [6], remaining at the site of injection until they have disintegrated. "
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