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Induction of systemic and mucosal immunity and maintenance of its memory was investigated in 12 young male cynomolgus monkeys after intranasal instillation of flu vaccine using a new mucosal adjuvant SF-10 derived from pulmonary surfactant constituents. Split-product of influenza virus A/California/7/2009(H1N1)pdm hemagglutinin vaccine (HAv) at 15 μg with or without SF-10 and the adjuvant alone were instilled intranasally three times every 2 weeks. SF-10-adjuvanted HAv (SF-10-HAv) elicited significantly higher HAv-specific IgG and hemagglutinin inhibition (HI) titers in serum and HAv-specific secretory IgA and its neutralizing activities in nasal washes compared with HAv antigen and SF-10 alone. Significant cross-neutralizing activities of nasal washes after the third vaccination to several other H1N1 and H3N2 strains were observed. HI titers in serum and neutralizing activities in nasal washes reached peak levels at 6 weeks after initial vaccination, then gradually decreased after 10 weeks and returned to the baseline levels at 36 weeks. A single intranasal revaccination of SF-10-HAv at 36 weeks rapidly and significantly increased both immunity in serum and nasal washes compared with naïve monkeys. Revaccination by one or two doses achieved almost maximal immunity at 2 or 4 weeks after instillation. Statistically significant adverse effects ( e.g. , body weight loss, elevated body temperature, nasal discharge, change in peripheral blood leukocyte and platelet counts) were not observed for 2 weeks after vaccination of SF-10-HAv, HAv or SF-10 and also during the experimental period. These results in young monkey model suggest the potential of clinical use SF-10 for intranasal flu vaccine. [ABSTRACT FROM AUTHOR]

Background We found previously that bovine pulmonary Surfacten® used in newborns with acute respiratory distress syndrome is a safe and efficacious antigen vehicle for intranasal vaccination. Objectives The objective of this study was to industrially produce a synthetic adjuvant mimicking Surfacten® for clinical use without risk of bovine spongiform encephalopathy. Methods We selected three Surfacten lipids and surfactant protein ( SP)-C as essential constituents for adjuvanticity. For replacement of the hydrophobic SP-C, we synthesized SP-related peptides and analyzed their adjuvanticity. We evaluated lyophilization to replace sonication for the binding of influenza virus hemagglutinin ( HA) to the synthetic adjuvant. We also added a carboxy vinyl polymer ( CVP) to the synthetic adjuvant and named the mixture as SF-10 adjuvant. HA combined with SF-10 was administered intranasally to mice, and induction of nasal-wash HA-specific secretory IgA (s-IgA) and serum IgG with Th1-/Th2-type cytokine responses in nasal cavity and virus challenge test were assessed. Results and Conclusions Intranasal immunization with HA-SF-10 induced significantly higher levels of anti- HA-specific nasal-wash s- IgA and serum IgG than those induced by HA-poly(I:C), a reported potent mucosal vaccine, and provided highly efficient protection against lethal doses of virus challenge in mice. Anti- HA-specific serum IgG levels induced by HA-SF-10 were almost equivalent to those induced by subcutaneous immunization of HA twice. Intranasal administration of HA-SF-10 induced balanced anti- HA-specific IgG1 and IgG2a in sera and IFN-γ- and IL-4-producing lymphocytes in nasal cavity without any induction of anti- HA IgE. The results suggest that HA-SF-10 is a promising nasal influenza vaccine and that SF-10 can be supplied in large quantities commercially. [ABSTRACT FROM AUTHOR]

Abstract: We have reported that Surfacten® (St), a bovine pulmonary surfactant free of antigenic c-type lectins, is a useful mucosal adjuvant for nasal vaccination. To prepare ample supplies a synthetic adjuvant that mimics St, we analyzed essential constituents of St for mucosal adjuvanticity. Intranasal inoculation of influenza virus hemagglutinin (HA) vaccine combined with St free of surfactant protein (SP)-C resulted in failure of HA vaccine delivery to dendritic cells and loss of local and systemic immune responses. Naïve bovine SP-C, synthetic human or bovine SP-C peptide reconstituted with three major St lipids restored delivery activity and local and systemic immune responses to levels similar to those of St and provided almost complete protection against lethal doses of influenza virus challenge in mice. The delivery of fluoresceinated HA vaccine to cultured dendritic cells was significantly enhanced by co-administration of St or synthetic adjuvant, and moderately stimulated the expression of MHC class II and CD86. In addition, both St and synthetic adjuvant markedly sustained HA vaccine and achieved a wide antigen distribution in murine nasal cavity. These results suggest that synthetic mucosal adjuvant reconstituted with SP-C peptide and major St lipids is useful for ample supply of the potent mucosal adjuvant as an antigen delivery vehicle for intranasal vaccination. [Copyright &y& Elsevier]

Abstract: Immune responses and side effects of intranasally administered flu vaccine with the commercial product Surfacten, a modified bovine pulmonary surfactant, were investigated in minipigs. The use of minipigs was based on the anatomical resemblance of nasal lymph nodes, the principal antigen uptake site of respiratory mucosal immunity, between pig and human. Intranasal instillation of HA vaccine adjuvanted with Surfacten elicited significantly higher serum hemagglutination inhibition titers than the antigen alone, with wide cross-neutralizing activities of secretory IgA in nasal washes. No significant induction of inflammatory cytokines or migration of inflammatory cells was observed at the site of immunization or serum after the first immunization. These data suggest the potential usefulness of Surfacten for mucosal vaccination. [Copyright &y& Elsevier]

Influenza A virus (IAV) is one of the most common infectious pathogens in humans. Entry of this virus into cells is primarily determined by host cellular trypsin-type processing proteases, which proteolytically activate viral membrane fusion glycoprotein precursors. Human IAV and murine parainfluenza virus type 1 Sendai virus are exclusively pneumotropic, and the infectious organ tropism of these viruses is determined by the susceptibility of the viral envelope glycoprotein to cleavage by proteases in the airway. Proteases in the upper respiratory tract are suppressed by secretory leukoprotease inhibitor, and those in the lower respiratory tract are suppressed by pulmonary surfactant, which by adsorption inhibits the interaction between the proteases and viral membrane proteins. Although the protease activities are predominant over the activities of inhibitory compounds under normal airway conditions, intranasal administration of inhibitors was able to significantly suppress multi-cycles of viral replication in the airway. In addition, we identified chemical agents that could act as defensive factors by up-regulating the levels of the natural inhibitors and immunoglobulin A (IgA) in airway fluids. One of these compounds, ambroxol, is a mucolytic and anti-oxidant agent that stimulates the release of secretory leukoprotease inhibitor and pulmonary surfactant in the early phase, and IgA in the late phase of infection at an optimal dose, i.e. a dose sufficient to inhibit virus proliferation and increase the survival rate of animals after treatment with a lethal dose of IAV. Another agent, clarithromycin, is a macrolide antibiotic that increases IgA levels through augmentation of interleukin-12 levels and mucosal immunization in the airway. In addition to the sialidase inhibitors, which prevent the release of IAV from infected cells, inhibitors of the processing proteases and chemical agents that augment mucosal immunity and/or levels of the relevant defensive compounds may also ultimately prove to be useful as new anti-influenza agents. [ABSTRACT FROM AUTHOR]