Back to the future: Immunization with M-001 prior to trivalent influenza vaccine in 2011/12 enhanced protective immune responses against 2014/15 epidemic strain.

We previously reported a 2011/12 study in elderly showing that immunization with the universal influenza vaccine candidate, M-001, three weeks before administering trivalent influenza vaccine (TIV) enhanced seroconversion of Hemagglutination Inhibition (HAI) antibodies against known influenza vaccine strains circulating at that time. We now report that those subjects primed with M-001 prior to TIV in 2011 also showed, in their 2011 sera, significantly more HAI antibodies with improved seroprotection and seroconversion against strain A/Switzerland/9715293/2013(H3N2-like) that caused the 2014/15 influenza epidemic and that wasn't known to circulate in 2011/12. These data indicate that M-001 can provide broadened enhanced immunity extending even to influenza strains destined to circulate in future years. The fact that M-001 stimulates T cell activation and is devoid of HA hypervariable epitopes indicates that such broadened HAI responses effected by M-001 priming is due to extensive T cell priming.

Intranasal Protollin-formulated recombinant SARS S-protein elicits respiratory and serum neutralizing antibodies and protection in mice.

The feasibility of developing a prophylactic vaccine against SARS was assessed by comparing the immune responses elicited by immunizing mice with a recombinant SARS spike glycoprotein (S-protein) formulated with different adjuvants, given by different routes. In both young and aged mice, an intranasal Protollin-formulated S-protein vaccine elicited high levels of antigen-specific IgG in serum, comparable to those elicited by an intramuscular Alum-adsorbed S-protein vaccine. Serum antibodies were shown to be virus neutralizing. Intranasal immunization of young mice with the Protollin-formulated vaccine elicited significant levels of antigen-specific lung IgA in contrast to mice immunized with the intramuscular vaccine in which no antigen-specific lung IgA was detected. Following live virus challenge of aged mice, no virus was detected in the lungs of intranasally immunized mice, in contrast to intramuscularly immunized mice whose lung virus titers were comparable to those observed in control mice.

Intranasal administration of a proteosome-influenza vaccine is well-tolerated and induces serum and nasal secretion influenza antibodies in healthy human subjects.

Two randomized, blinded, active comparator-controlled trials of a prototype monovalent A/Beijing/262/95 (H1N1) - proteosome vaccine delivered by intranasal spray were performed in healthy adults. Overall, the intranasal proteosome-adjuvanted vaccine was well-tolerated with only mild stuffy nose and rhinorrhea seen more frequently in recipients of vaccine than in recipients of intranasal saline, and there were no serious adverse events. The intranasal proteosome-adjuvanted vaccine induced serum hemagglutination inhibiting (HAI) and nasal secretory IgA (sIgA) responses specific for the influenza antigen. Serum HAI responses were most influenced by the dosage level, whereas mucosal sIgA responses, although demonstrable with both single-dose and two-dose vaccine regimens, appeared to be greater in response to two-dose regimens (regardless of dose level). Further evaluation of mucosal influenza immunization using the proteosome adjuvant/delivery system is clearly warranted.

Intranasal Protollin/F1-V vaccine elicits respiratory and serum antibody responses and protects mice against lethal aerosolized plague infection.

F1-V is a recombinant plague antigen comprising the capsular (F1) and virulence-associated (V) proteins. Given intramuscularly with Alhydrogel, it protects mice against challenge, but is less effective in non-human primates against high-dose aerosolized Yersinia pestis challenge, perhaps because it fails to induce respiratory immunity. Intranasal immunization of mice with F1-V formulated with a Proteosome-based adjuvant (Protollin), elicited high titers of specific IgA in lungs whereas intranasal F1-V alone or intramuscular Alhydrogel-adsorbed F1-V did not. The Protollin-adjuvanted F1-V vaccine also induced high serum titers of specific IgG, comparable to those induced by intramuscular Alhydrogel-adsorbed F1-V. Mice immunized intranasally with Protollin-F1-V were 100% protected against aerosol challenge with 170 LD50 of Y. pestis and 80% against 255 LD50.

Safety and immunogenicity of a Proteosome -trivalent inactivated influenza vaccine, given nasally to healthy adults.

We studied the safety and immunogenicity of a nasally administered vaccine comprising three monovalent inactivated influenza antigens (A/New Caledonia/20/99 (H1N1), A/Panama/2007/99 (H3N2), and B/Guangdong/120/2000) non-covalently associated with outer membrane proteins of Neisseria meningitidis (Proteosome) in normal, healthy adults. In a randomized, double-blind trial participants (n = 78) were allocated to placebo or a single nasal dose of vaccine containing 15, 30, or 45 microg of each of the three HA antigens, or two nasal doses containing 30 microg of each HA, separated by 2 weeks. The vaccine was generally well tolerated in all doses tested, and in a one or two-dose schedule. A shallow vaccine reactogenicity dose-response was seen. The most common local reaction was nasal congestion, which occurred in up to 48.3% of vaccine recipients in days 0-6 after vaccine but was mild and self-limiting; this reaction was not significantly more common among active vaccine recipients than placebo recipients. Mild to moderate headache was the most commonly reported systemic reactogenicity complaint in all treatment groups, and was the only solicited complaint to increase significantly in frequency after a second active dose. No severe systemic reactions occurred. A positive and statistically significant antibody response was observed, in serum and in nasal secretions, to increasing dose for all three antigens. Serum HAI titre responses and nasal secretory IgA immune responses were elicited against all three antigens. Further testing of this nasal influenza vaccine is warranted to determine its safety and immunogenicity in these populations and its efficacy in the prevention of clinical illness.

A novel intranasal Protollin-based measles vaccine induces mucosal and systemic neutralizing antibody responses and cell-mediated immunity in mice.

Protollin-MV is a vaccine produced by mixing split measles virus (MV) antigen with the novel adjuvant Protollin (Neisseria meningitidis outer membrane proteins non-covalently complexed with Shigella flexneri 2a lipopolysaccharide). Intranasal immunization of mice with two or three doses of Protollin-MV induces both serum IgG and mucosal IgA with strong neutralizing activity. There is a dose-dependent shift towards lower IgG1:IgG2a ratios and MV-specific IFNgamma production in splenocytes. Intranasal Protollin-MV can therefore induce systemic and mucosal neutralizing antibody responses as well as elicit a balanced TH1/TH2-type response.

Toward the development of an antidisease, transmission-blocking intranasal vaccine for group a streptococcus.

Infection with group A streptococcus (GAS) may result in a number of clinical conditions, including the potentially life-threatening postinfectious sequelae of rheumatic fever and rheumatic heart disease. As part of the search for a vaccine to prevent GAS infection, a conformationally constrained and minimally conserved peptide, J14, from the M protein of GAS has been defined. In the present study, J14 was formulated with bacterial outer membrane proteins (proteosomes) and then intranasally administered to outbred mice without additional adjuvant. Such immunization led to high titers of J14-specific serum immunoglobulin (Ig) G and mucosal IgA. After upper respiratory tract GAS challenge, immunized mice demonstrated increased survival and reduced GAS colonization of the throat.

Protollin: a novel adjuvant for intranasal vaccines.

Protollin is a novel adjuvant comprising Proteosomes non-covalently complexed with LPS. Intranasal immunization of mice with Protollin combined with detergent-split influenza antigens (HA) or recombinant influenza hemagglutinin (rHA) enhanced serum IgG and mucosal IgA levels by up to 250-fold compared with immunization with the antigens alone. IFN-gamma responses were also enhanced compared to the levels produced by splenocytes from mice immunized with antigen alone, while production of IL-5 was abrogated. Mice immunized with Protollin-rHA were completely protected against lethal challenge with influenza virus, demonstrating that Protollin is an effective mucosal adjuvant for prophylactic vaccines.

Intranasal immunization with multivalent group A streptococcal vaccines protects mice against intranasal challenge infections.

We have previously shown that a hexavalent group A streptococcal M protein-based vaccine evoked bactericidal antibodies after intramuscular injection. In the present study, we show that the hexavalent vaccine formulated with several different mucosal adjuvants and delivered intranasally induced serum and salivary antibodies that protected mice from intranasal challenge infections with virulent group A streptococci. The hexavalent vaccine was formulated with liposomes with or without monophosphorylated lipid A (MPL), cholera toxin B subunit with or without holotoxin, or proteosomes from Neisseria meningitidis outer membrane proteins complexed with lipopolysaccharide from Shigella flexneri. Intranasal immunization with the hexavalent vaccine mixed with these adjuvants resulted in significant levels of antibodies in serum 2 weeks after the final dose. Mean serum antibody titers were equivalent in all groups of mice except those that were immunized with hexavalent protein plus liposomes without MPL, which were significantly lower. Salivary antibodies were also detected in mice that received the vaccine formulated with the four strongest adjuvants. T-cell proliferative assays and cytokine assays using lymphocytes from cervical lymph nodes and spleens from mice immunized with the hexavalent vaccine formulated with proteosomes indicated the presence of hexavalent protein-specific T cells and a Th1-weighted mixed Th1-Th2 cytokine profile. Intranasal immunization with adjuvanted formulations of the hexavalent vaccine resulted in significant levels of protection (80 to 100%) following intranasal challenge infections with type 24 group A streptococci. Our results indicate that intranasal delivery of adjuvanted multivalent M protein vaccines induces protective antibody responses and may provide an alternative to parenteral vaccine formulations.

A nasal Proteosome influenza vaccine containing baculovirus-derived hemagglutinin induces protective mucosal and systemic immunity.

The potential for enhancing the immunogenicity of recombinant (baculovirus-derived) influenza hemagglutinin (rHA) was investigated by comparing the immune responses elicited in mice by an intranasal (i.n.) rHA formulated with Proteosomes, with those induced by intramuscular (i.m.) or i.n. rHA alone. The Proteosome-rHA vaccine induced mucosal responses in the respiratory tract, as well as high serum IgG and hemagglutination inhibition (HAI) titers. In contrast, rHA alone given i.m. induced serum IgG without mucosal responses and was ineffective at inducing either mucosal or systemic responses when given i.n. Only mice immunized with the Proteosome-rHA vaccine were completely protected from both death and acute morbidity following live virus challenge, indicating that the i.n. Proteosome-rHA vaccine induced more complete protective immunity than the same doses of unformulated rHA given i.n. or i.m.