A SARS-CoV-2 Wuhan spike virosome vaccine induces superior neutralization breadth compared to one using the Beta spike.

Current SARS-CoV-2 vaccines are effective, but long-term protection is threatened by the emergence of virus variants. We generated a virosome vaccine containing the Beta spike protein and compared its immunogenicity in mice to a virosome vaccine containing the original Wuhan spike. Two administrations of the virosomes induced potent SARS-CoV-2 neutralizing antibodies in both vaccine groups. The level of autologous neutralization in Beta-vaccinated mice was similar to the level of autologous neutralization in Wuhan-vaccinated mice. However, heterologous neutralization to the Wuhan strain in Beta-vaccinated mice was 4.7-fold lower than autologous neutralization, whereas heterologous neutralization to the Beta strain in Wuhan-vaccinated mice was reduced by only 1.9-fold compared to autologous neutralization levels. In addition, neutralizing activity against the D614G, Alpha and Delta variants was also significantly lower after Beta spike vaccination than after Wuhan spike vaccination. Our results show that Beta spike vaccination induces inferior neutralization breadth. These results are informative for programs aimed to develop broadly active SARS-CoV-2 vaccines.

Intradermal and virosomal influenza vaccines for preventing influenza hospitalization in the elderly during the 2011-2012 influenza season: a comparative effectiveness study using the Valencia health care information system.

BACKGROUND: The use of intradermal vaccination or virosomal vaccines could increase protection against influenza among the vulnerable population of older adults. Studies assessing the comparative effectiveness of these two influenza vaccine types in this age group are lacking. METHODS: We conducted a retrospective cohort study to estimate the comparative effectiveness of intradermal seasonal trivalent-influenza vaccine (TIV) delivered by a microneedle injection system and a virosomal-TIV intramuscularly delivered for prevention of influenza hospitalization in non-institutionalized adults aged ≥65 years. We obtained administrative data on immunization status and influenza hospitalization for the 2011-2012 influenza season, and used Cox regression models to assess comparative effectiveness. We estimated crude and adjusted (age, sex, comorbidity, pharmaceutical claims, recent pneumococcal vaccination and number of hospitalizations for all causes other than influenza between the previous and current influenza seasons) hazard ratios (HR). RESULTS: Overall, 164,021 vaccinated subjects were evaluated. There were 127 hospitalizations for influenza among 62,058 subjects, contributing 914,740 person-weeks at risk in the virosomal-TIV group, and 133 hospitalizations for influenza among 101,963 subjects, contributing 1,504,570 person-weeks at risk in the intradermal-TIV group. The crude HR of intradermal-TIV relative to virosomal-TIV was 0.64 (95% confidence interval (CI): 0.50-0.81), and the adjusted Cox estimated HR was 0.67 (95% CI: 0.52-0.85). CONCLUSIONS: During the 2011-2012 influenza season the risk of hospitalization for influenza was reduced by 33% in non-institutionalized elderly adults who were vaccinated with intradermal-TIV compared with virosomal-TIV.

A virosomal formulated Her-2/neu multi-peptide vaccine induces Her-2/neu-specific immune responses in patients with metastatic breast cancer: a phase I study.

We have previously shown in mice that vaccination with three Her-2-peptides representing B-cell epitopes of the extracellular domain of Her-2/neu induces Her-2/neu-specific IgG antibodies with strong anti-tumor activity in vitro and in vivo. We have now finalized a phase I clinical trial with an anti-Her-2/neu vaccine-construct of immunopotentiating reconstituted influenza virosomes with the three peptides in patients with metastatic breast cancer (MBC). Ten MBC patients with low protein overexpression of Her-2/neu of MBC (+ or ++ upon immunohistochemistry, FISH negative) and positive hormone receptor status were enrolled in a single center phase I study. The virosomal formulated vaccine, consisting of 10 microg/peptide, was intramuscularly applied three times on days 1, 28, and 56. The primary endpoint of the study, which lasted 12 weeks, was safety, the secondary endpoint immunogenicity. Local erythema at the injection site was the only vaccine-related side effect occurring in four patients. In 8 of 10 patients an increase in peptide-specific antibody titer measured by ELISA was found. Importantly, the induced antibodies were also directed against the native Her-2/neu protein. Cellular immune responses, as measured by in vitro production of IL-2, IFN-c, and TNF-a of PBMCs showed a marked increase after vaccination in the majority of vaccinees. Notably, the number of CD4+CD25+Foxp3+T regulatory cells, which were significantly increased compared to healthy controls prior to vaccination, was markedly reduced following vaccination. In all, the immunological responses after vaccination indicated that the patients in stage IV of disease were immunocompetent and susceptible to vaccination. The Her-2/neu multipeptide vaccine was safe, well tolerated and effective in overcoming immunological tolerance to Her-2/neu. The induction of anti-Her-2-specific antibodies could result in clinical benefit comparable to passive anti-Her-2 antibody therapy.

Eleven years of Inflexal V-a virosomal adjuvanted influenza vaccine.

Since the introduction to the Swiss market in 1997, Crucell (former Berna Biotech Ltd.), has sold over 41 million doses worldwide of the virosomal adjuvanted influenza vaccine, Inflexal V. Since 1992, 29 company sponsored clinical studies investigating the efficacy and safety of Inflexal V have been completed in which 3920 subjects participated. During its decade on the market, Inflexal V has shown an excellent tolerability profile due to its biocompatibility and purity. The vaccine contains no thiomersal or formaldehyde and its purity is reflected in the low ovalbumin content. By mimicking natural infection, the vaccine is highly efficacious. Inflexal V is the only adjuvanted influenza vaccine licensed for all age groups and shows a good immunogenicity in both healthy and immunocompromised elderly, adults and children. This review presents and discusses the experience with Inflexal V during the past decade.

Anti-angiogenetic effects of immune-reconstituted influenza virosomes assembled with parathyroid hormone-related protein derived peptide vaccine.

BACKGROUND: C-IRIV/PTR-4 is a novel anticancer vaccine construct composed of immune-reconstituted influenza virosomes (IRIV) assembled with the PTH-rP derived peptide (PTR)-4, a synthetic CTL epitope with HLA-A(*)02.01 amino acid binding motifs. This peptide is able to generate a human PTH-rP specific CTL response with anti-tumor activity in vitro and in mice. MATERIALS AND METHODS: We have investigated the immunological and preventive anti-tumor activity of C-IRIV/PTR-4 compared with the soluble PTR-4 peptide, in HHD mice inoculated with autologous PTH-rP+ tumor cells. RESULTS: Peptide vaccination with either a soluble and an IRIV formulation showed similar immunological activity and the ability to purge the tumor tissue of tumor cell clones able to produce the target antigen (PTR-rP). The most efficient protection from tumor growth was however observed in animals vaccinated with C-IRIV/PTR-4 in which an additional IRIV related anti-angiogenetic effect was detected in the tumor tissue. CONCLUSIONS: These results confirm the immunological activity of PTR-4 vaccination and suggest a more efficacious therapeutic potential of C-IRIV/PTR-4 against bone metastases and malignancies like breast, prostate and lung which very often over-express PTH-rP.

Vaccination against IL-17 suppresses autoimmune arthritis and encephalomyelitis.

Interleukin 17 is a T cell-derived cytokine that induces the release of pro-inflammatory mediators in a wide range of cell types. Recently, a subset of IL-17-producing T helper cells (Th17) distinct from Th1 and Th2 cells has been described, which constitutes a new T cell polarization state. Aberrant Th17 responses and overexpression of IL-17 have been implicated in a number of autoimmune disorders including rheumatoid arthritis and multiple sclerosis. Molecules blocking IL-17 such as IL-17-specific monoclonal antibodies have proved to be effective in ameliorating disease in animal models. Hitherto, active immunization targeting IL-17 is an untried approach. Herein we explore the potential of neutralizing IL-17 by active immunization using virus-like particles conjugated with recombinant IL-17 (IL-17-VLP). Immunization with IL-17-VLP induced high levels of anti-IL-17 antibodies thereby overcoming natural tolerance, even in the absence of added adjuvant. Mice immunized with IL-17-VLP had lower incidence of disease, slower progression to disease and reduced scores of disease severity in both collagen-induced arthritis and experimental autoimmune encephalomyelitis. Active immunization against IL-17 therefore represents a novel therapeutic approach for the treatment of chronic inflammatory diseases.

Neutralization of IL-17 by active vaccination inhibits IL-23-dependent autoimmune myocarditis.

The most common reason for heart failure in young adults is dilated cardiomyopathy often resulting from myocarditis. Clinical studies and animal models provide evidence that an autoimmune response against heart myosin is the underlying reason for the disease. IL-12 has been suggested to play a key role in development of experimental autoimmune myocarditis (EAM), as IL-12p40 and IL-12Rbeta1 knockouts are protected from disease. In this study, we have compared IL-12p40-/- mice, IL-12p35-/- mice and mice treated with a neutralizing IL-23 antibody in EAM and found that in fact IL-23, not IL-12, is responsible for inflammatory heart disease. However, these cytokines appear to have redundant activity for priming and expansion of autoreactive CD4 T cells, as specific T cell proliferation was only defective in the absence of both cytokines. IL-23 has been suggested to promote a pathogenic IL-17-producing T cell population. We targeted IL-17 by capitalizing on an active vaccination approach that effectively breaks B cell tolerance. Neutralization of IL-17 reduced myocarditis and heart autoantibody responses, suggesting that IL-17 is the critical effector cytokine responsible for EAM. Thus, targeting of IL-23 and IL-17 by passive and active vaccination strategies holds promise as a therapeutic approach to treat patients at risk for development of dilated cardiomyopathy.

Immune-reconstituted influenza virosome containing CD40L gene enhances the immunological and protective activity of a carcinoembryonic antigen anticancer vaccine.

The correct interaction of a costimulatory molecule such as CD40L with its contrareceptor CD40 expressed on the membrane of professional APCs, provides transmembrane signaling that leads to APC activation. This process can be exploited to significantly improve the efficacy of cancer vaccines and the outcome of a possible cancer vaccine-induced, Ag-specific CTL response. Therefore, we investigated whether a novel intranasal delivery of immune-reconstituted influenza virosomes (IRIV), assembled with the CD40L gene (CD40L/IRIV), could be used to improve protective immunity and the Ag-specific CTL response against carcinoembryonic Ag (CEA) generated with a novel vaccine constituted of IRIV assembled with the CEA gene (CEA/IRIV). Our results suggest that CD40L/IRIV was able to augment CEA-specific CTL activity and CEA-specific protective immunity induced by CEA/IRIV most likely through the induction of a CTL response associated with a Th1 phenotype. In conclusion, we provide evidence that CD40L/IRIV, by acting through the CD40L/CD40 signaling pathway, acts as an immune-adjuvant that could increase the efficacy of a CEA-specific cancer vaccine, which could provide an efficacious new strategy for cancer therapy.

Cytotoxic T-cell response against steroidogenic acute regulatory protein using DNA vaccination followed by vaccinia virus infection in a mouse adrenal carcinoma model.

Adrenocortical carcinoma (ACC) is still one of the most devastating human tumors with a five year survival as low as 20 %. In a previous study, we showed that DNA vaccination followed by vaccinia virus was able to break immune tolerance against murine steroidogenic acute regulatory (mStAR). Prophylactic vaccination in syngenic mice resulted in protective immunity against Sp2-0 tumor cells expressing mStAR. However, approximately a third of the animals developed tumors despite vaccination. This prompted us to investigate whether vaccination failure is responsible for this phenomenon. BALB/cBALB/c mice (in groups of 6 - 9 animals) were vaccinated intramuscularly by injection of cDNA expression vectors encoding mStAR three times at weekly intervals. This was followed by a recombinant vaccinia virus (rVV-mStAR) infection to boost immune response. Ten days after the last vaccination, Sp2-mStAR or parental Sp2-0 cells (as controls) were injected s. c. Tumor development was monitored by daily palpation. Approximately two weeks later, the animals were sacrificed and the spleens removed. After restimulation with the cell lines expressing mStAR, the splenocytes were tested for presence of mStAR self-reactive cytotoxic T-lymphocytes using ELISPOT analysis. With this approach, we were able to show that those animals protected from tumor growth had a specific T-cell response against StAR whereas mice without a specific T-cell response developed Sp2-mStAR tumors. Our data demonstrate that vaccination failure, probably due to the low antigenicity of mStAR, is responsible for tumor growth in our model system.

New technology platforms in the development of vaccines for the future.

The desire for improved quality of life in both industrialised and under-developed nations has led to the quest for greater understanding and subsequent prevention and treatment of diseases. Here we discuss some of the latest of modern medicine's approaches to vaccination and disease treatment. Our main subject of discussion being the novel antigen delivery systems termed immunopotentiating reconstituted influenza virosomes (IRIVs) and their use as vaccines. Particular attention is paid to the currently licensed Epaxal and Inflexal V, good examples of the improvements being made in vaccinology. Alternative uses of virosomes such as peptide delivery, cytosolic drug delivery and gene delivery are also considered, highlighting the flexibility of the IRIV formulation and method of action. The paper concludes with consideration of alternative novel approaches to vaccinology including bacterial carriers for DNA vaccines, recombinant MV vaccines and polysaccharide-protein conjugates.

Inflexal V a trivalent virosome subunit influenza vaccine: production.

Inflexal V, a novel virosome-based trivalent influenza vaccine, has been shown to be highly immunogenic and well tolerated in children, young adults, and the elderly. Here we discuss the techniques for the manufacture of Inflexal V, highlighting the purity and consistency of the manufacturing process. Key factors to be taken into account in the construction of Inflexal V are the retention of the natural presentation of antigens, its biodegradability and the presentation of few adverse events. The constituents of the vaccine were also carefully considered based on suitability for human use, adjuvanticity and an innate lack of toxicity.

Efficacy of intranasal virosomal influenza vaccine in the prevention of recurrent acute otitis media in children.

To evaluate the efficacy of an intranasal, inactivated, virosomal subunit influenza vaccine for prevention of new episodes of acute otitis media (AOM) in children with recurrent AOM, 133 children aged 1-5 years were randomized to receive the vaccine (n=67) or no vaccination (n=66). During a 6-month period, 24 (35.8%) vaccine recipients had 32 episodes of AOM; 42 (63.6%) control subjects had 64 episodes. The overall efficacy of vaccination in preventing AOM was 43.7% (95% confidence interval, 18.6-61.1; P=.002). Children vaccinated before influenza season had a significantly better outcome than did those vaccinated after the onset of influenza season. The cumulative duration of middle ear effusion was significantly less in vaccinated children than in control subjects. Data suggest that the intranasal virosomal influenza vaccine might be considered among the options for the prevention of AOM in children <5 years old with recurrent AOM.

Perspectives: towards a peptide-based vaccine against hepatitis C virus.

Hepatitis C virus (HCV) is a widespread infectious disease in humans with the negative implication of becoming chronic in most persons. Patients infected with HCV are at risk of liver cirrhosis or hepatocellular carcinoma at later stages. In contrast to hepatitis A and hepatitis B, there is no immunization yet available, neither prophylactic nor therapeutic. Thus, there is an urgent need to develop a safe, protective vaccine against this fatal disease. Developing countries are even more at risk for HCV. There are currently a number of scientific approaches aimed towards solving this problem. Taking both risks and costs of immunization into consideration, a peptide-based vaccine may be a reasonable prophylactic protection. Also, it might be of therapeutic use in already infected patients by increasing a specific CTL response against HCV. In our lab, we are focusing on immunopotentiating reconstituted influenza virosomes (IRIVs) as carriers for immunogenic HLA-A2-restricted core epitopes to induce peptide-specific cytotoxic T lymphocytes (CTLs). The IRIVs are similar to liposomes, but in addition contain influenza-derived hemagglutinin and neuraminidase on their outer surface which makes them fusogenic, thus, permitting antigen delivery to host cells. So far, virosomes have been successfully used for vaccine development and as a result a virosomal vaccine against both influenza virus (Inflexal) BERNA) and hepatitis A virus (HAV) (Epaxal) BERNA) already exist on the market. This paper focuses on the importance of development of a successful vaccine against HCV and, more specifically, we discuss the use, advantages and disadvantages of a peptide-based vaccine. A brief report of our latest findings will be included.