Effect of sublingual administration of interferon-α on the immune response to influenza vaccination in institutionalized elderly individuals

Vaccine Strategies to Elicit Mucosal Immunity

Vaccines are essential tools to prevent infection and control transmission of infectious diseases that threaten public health. Most infectious agents enter their hosts across mucosal surfaces, which make up key first lines of host defense against pathogens. Mucosal immune responses play critical roles in host immune defense to provide durable and better recall responses. Substantial attention has been focused on developing effective mucosal vaccines to elicit robust localized and systemic immune responses by administration via mucosal routes. Mucosal vaccines that elicit effective immune responses yield protection superior to parenterally delivered vaccines. Beyond their valuable immunogenicity, mucosal vaccines can be less expensive and easier to administer without a need for injection materials and more highly trained personnel. However, developing effective mucosal vaccines faces many challenges, and much effort has been directed at their development. In this article, we review the history of mucosal vaccine development and present an overview of mucosal compartment biology and the roles that mucosal immunity plays in defending against infection, knowledge that has helped inform mucosal vaccine development. We explore new progress in mucosal vaccine design and optimization and novel approaches created to improve the efficacy and safety of mucosal vaccines.

Advances in Infectious Disease Vaccine Adjuvants

Vaccines are one of the most significant medical interventions in the fight against infectious diseases. Since their discovery by Edward Jenner in 1796, vaccines have reduced the worldwide transmission to eradication levels of infectious diseases, including smallpox, diphtheria, hepatitis, malaria, and influenza. However, the complexity of developing safe and effective vaccines remains a barrier for combating many more infectious diseases. Immune stimulants (or adjuvants) are an indispensable factor in vaccine development, especially for inactivated and subunit-based vaccines due to their decreased immunogenicity compared to whole pathogen vaccines. Adjuvants are widely diverse in structure; however, their overall function in vaccine constructs is the same: to enhance and/or prolong an immunological response. The potential for adverse effects as a result of adjuvant use, though, must be acknowledged and carefully managed. Understanding the specific mechanisms of adjuvant efficacy and safety is a key prerequisite for adjuvant use in vaccination. Therefore, rigorous pre-clinical and clinical research into adjuvant development is essential. Overall, the incorporation of adjuvants allows for greater opportunities in advancing vaccine development and the importance of immune stimulants drives the emergence of novel and more effective adjuvants. This article highlights recent advances in vaccine adjuvant development and provides detailed data from pre-clinical and clinical studies specific to infectious diseases. Future perspectives into vaccine adjuvant development are also highlighted.

Cytokines and growth factors in a biologic product obtained from patients' urine as immune-modulators to treat autoimmune and allergic diseases

At "Instituto de Alergias y Autoinmunidad Dr. Maximiliano Ruiz Castañeda, A.C." in Mexico City, a non-traditional health care center focused on the treatment of autoimmune and allergic diseases using personalized medicine, an alternative treatment referred to as an "immune-modulator" has been developed. In this study, we will refer to this treatment substance as the "immune-modulator." In brief, a urine sample is collected from the patient and processed to obtain the peptide fraction, which is conditioned and then administered sublingually to the patient. Sample processing involves multiple steps aimed at the removal of toxic compounds and enrichment for cytokines, growth factors, and other immune peptides that may contribute to the function of the immune-modulator. This treatment has been administered for many years, and patients testify that it is useful and reliable. Despite the benefits of this treatment, the molecular mechanisms underlying its effects have not been thoroughly investigated. Therefore, this study aims to identify immunoregulatory peptides, such as cytokines and growth factors, in the immune-modulator. Urine and immune-modulator concentrations of cytokines and growth factors were assessed using a Luminex assay. Twenty-one cytokines and growth factors were identified in immune-modulator samples. MCP-1 was identified in 100% of the samples; MIP-1β, IL-8, RANTES, INF-γ, and IP-10 were identified in approximately 65-70% of samples; IL5, IL-1B, and IL-17 in 50-60%; eotaxin, VEGF, IL-6, and FGF in about 40%; MIP-1α, IL-9, GM-CSF, G-CSF, IL-12, and IL-15 in about 20-30%; and IL-13 and PDGF-bb were identified in <6% of samples. Additionally, patients exhibited significant changes in IL-1β, IFN-γ, and MCP-1 concentrations after treatment with the immune-modulator, whereas healthy individuals showed no significant change in response to the treatment. The immune-modulator is an alternative treatment based on the administration of cytokines and growth factors obtained from the urine of patients. In this study, its composition was characterized. The isolated products could be responsible for the effects of the immune-modulator. Further trials are required to evaluate the effective delivery of these molecules by the administration route described.

Role of type I interferon in inducing a protective immune response: perspectives for clinical applications

Type I IFNs (IFN-I) are antiviral cytokines endowed with many biological effects, including antitumor activity. Over the last 15 years, an ensemble of studies has revealed that these cytokines play a crucial role in the induction of a protective antitumor immune response. Early in vivo studies in mouse models have been instrumental for understanding the IFN-I-induced host-mediated mechanisms. IFN-α is currently recognized as a powerful inducer of the differentiation/activation of dendritic cells (DCs) and today IFN-α-conditioned DCs represent promising DC candidates for the development of therapeutic cancer vaccines. Moreover, data from pilot clinical trials support the concept of using IFN-α as an enhancer of the response of patients to cancer vaccines. Notably, endogenous IFN-I production does also play a critical role in the antitumor response to some chemotherapeutic agents. Thus, we can now envisage new strategies of clinical use of IFN-α, based on the injection of IFN-conditioned cells as well as the usage of these cytokines as cancer vaccine adjuvants, alone or in combination with other treatments (including epigenetic drugs) to induce an immunogenic cell death and a long lasting antitumor response.

Construction of a chimeric secretory IgA and its neutralization activity against avian influenza virus H5N1

Secretory immunoglobulin A (SIgA) acts as the first line of defense against respiratory pathogens. In this assay, the variable regions of heavy chain (VH) and Light chain (VL) genes from a mouse monoclonal antibody against H5N1 were cloned and fused with human IgA constant regions. The full-length chimeric light and heavy chains were inserted into a eukaryotic expressing vector and then transfected into CHO/dhfr-cells. The chimeric monomeric IgA antibody expression was confirmed by using ELISA, SDS-PAGE, and Western blot. In order to obtain a dimeric secretory IgA, another two expressing plasmids, namely, pcDNA4/His A-IgJ and pcDNA4/His A-SC, were cotransfected into the CHO/dhfr-cells. The expression of dimeric SIgA was confirmed by using ELISA assay and native gel electrophoresis. In microneutralization assay on 96-well immunoplate, the chimeric SIgA showed neutralization activity against H5N1 virus on MDCK cells and the titer was determined to be 1 : 64. On preadministrating intranasally, the chimeric SIgA could prevent mice from lethal attack by using A/Vietnam/1194/04 H5N1 with a survival rate of 80%. So we concluded that the constructed recombinant chimeric SIgA has a neutralization capability targeting avian influenza virus H5N1 infection in vitro and in vivo.

Recent developments in buccal and sublingual delivery systems

INTRODUCTION

There have been several advances in the delivery of drugs through the buccal mucosa over the last 5 years, which have resulted in a number of new buccal delivery products appearing on the market.

AREAS COVERED

This review discusses the most recent developments in the area of buccal and sublingual drug delivery, with a focus on marketed drugs. Likely future directions are also considered and reported.

EXPERT OPINION

The future potential of buccal and sublingual delivery systems looks favorable. It is envisaged that in the future, buccal and sublingual delivery technologies will provide a platform for the successful delivery of vaccines and antigens. It is also foreseen that physical means of enhancing drug uptake (e.g., sonophoresis, iontophoresis and electroporation) will be commercialized for buccal delivery, thereby expanding the current drug candidate list for this area. The formulation of delivery systems for photosensitizers in photodynamic therapy is a potential emerging area, while buccal and sublingual delivery, in general, is attractive for the development of intellectual property.

CAF01 potentiates immune responses and efficacy of an inactivated influenza vaccine in ferrets

Trivalent inactivated vaccines (TIV) against influenza are given to 350 million people every year. Most of these are non-adjuvanted vaccines whose immunogenicity and protective efficacy are considered suboptimal. Commercially available non-adjuvanted TIV are known to elicit mainly a humoral immune response, whereas the induction of cell-mediated immune responses is negligible. Recently, a cationic liposomal adjuvant (dimethyldioctadecylammonium/trehalose 6,6'-dibehenate, CAF01) was developed. CAF01 has proven to enhance both humoral and cell-mediated immune responses to a number of different experimental vaccine candidates. In this study, we compared the immune responses in ferrets to a commercially available TIV with the responses to the same vaccine mixed with the CAF01 adjuvant. Two recently circulating H1N1 viruses were used as challenge to test the vaccine efficacy. CAF01 improved the immunogenicity of the vaccine, with increased influenza-specific IgA and IgG levels. Additionally, CAF01 promoted cellular-mediated immunity as indicated by interferon-gamma expressing lymphocytes, measured by flow cytometry. CAF01 also enhanced the protection conferred by the vaccine by reducing the viral load measured in nasal washes by RT-PCR. Finally, CAF01 allowed for dose-reduction and led to higher levels of protection compared to TIV adjuvanted with a squalene emulsion. The data obtained in this human-relevant challenge model supports the potential of CAF01 in future influenza vaccines.

IFN-α as a vaccine adjuvant: recent insights into the mechanisms and perspectives for its clinical use

The IFN-α family are pleiotropic cytokines with the longest record of clinical use. Over the last decade, new biological effects of IFN-α on immune cells, including dendritic cells, have been described, supporting the concept that these cytokines can act as effective vaccine adjuvants. Recently, an important advance in our understanding of the mechanisms of interferon adjuvant activity has been achieved. Some clinical studies have been performed to assess the adjuvant activity in individuals immunized with preventive vaccines, showing variable results depending on interferon/vaccine formulation and vaccinated subjects. In spite of many data in animal models, little information is available on the possible advantage of utilizing IFN-α as an adjuvant for cancer vaccines in humans. Further clinical trials specifically designed to explore vaccine adjuvant activity are needed in order to define the best conditions for using IFN-α or IFN-α-conditioned dendritic cells for the development of therapeutic vaccines.

Low immunogenicity of seasonal trivalent influenza vaccine among patients receiving docetaxel for a solid tumour: results of a prospective pilot study

BACKGROUND

Patients receiving cytotoxic therapy for solid tumours are at risk of severe influenza. However, few data are available regarding the immunogenical efficacy of influenza vaccine in these patients.

METHODS

In this prospective study, 25 patients with breast (n=13) or prostate (n=12) cancer received a trivalent inactivated influenza vaccine along with docetaxel (Taxotere) administration. The influenza virus type A and B antibody titres were measured using haemagglutinin inhibition (Garten et al, 2009) before and 21 days after the vaccination. Seroconversion rate was defined as the percentage of patients with an increase in the serum titres ≥ 4 after vaccination.

RESULTS

Median age was 65 years (range: 33-87 years); 52% were females. Seroconversion rates were low: 28% (95% CI: 23.1-33.3) for H1N1, 8% (95% CI: 7.7-8.3) for H3N2 and 16% (95% CI: 7.7-25) for the B strain. The geometric mean titres ratios were 2.16 (H1N1), 1.3 (H3N2) and 1.58 (B). No serious adverse event (AE) related to the vaccine was reported. All the reported AE were from mild-to-moderate intensity.

CONCLUSION

In the patients receiving docetaxel for solid tumours, influenza vaccine triggers an immune response in only one third. Strategies using more immunogenic influenza vaccines must be evaluated in such patients.

Interferons as potential adjuvants in prophylactic vaccines

IMPORTANCE OF THE FIELD

Vaccines are still one of the best approaches to manage infectious diseases. Despite the advances in drug therapies, prophylactic medicine is still more cost efficient and minimizes the burden in the heath system. Despite all the research in vaccine development, many infectious diseases are still without an effective vaccine. The use of adjuvants in vaccines has been one successful strategy to increase efficacy. IFNs are widely expressed cytokines that have potent antiviral effects. These cytokines are the first line of defense against viral infections and have important roles in immuno surveillance for malignant cells. One of the most promising uses of IFNs is as adjuvants that are co-applied with antigen in vaccines.

AREAS COVERED IN THIS REVIEW

In this review, a cumulative analysis of many of the studies that have used IFN-α, -β, -γ and -λ as adjuvants between 1987 and the present suggests that many do possess the capacity to serve as potent immunoadjuvants for vaccination.

WHAT THE READER WILL GAIN

This review provides a very large collection of studies involving all types of IFNs used as adjuvants in vaccines using different vaccination strategies and various animal models.

TAKE HOME MESSAGE

It is clear that the use of IFNs not only improved the efficacy and safety of most vaccines, but also had important immunomodulatory effect directing T(H)1 immune responses.

Type I interferons as mediators of immune adjuvants for T- and B cell-dependent acquired immunity

Originally identified as antiviral substances produced by infected cells, type I interferons (IFN-I) are now known to have a wide range of additional activities within both the innate and adaptive immune response. Here we review properties of IFN-I contributing to their 'natural immune adjuvant' character, and their important role for the function of complete Freund's adjuvant (CFA) and the TLR9-dependent immune adjuvant IC31. We show data to demonstrate that treatment with IFN-I boosts the ability of vaccine/adjuvant combinations to induce peptide-specific CTL in both young and old mice. We view these findings in the perspective of previous clinical applications of IFN-I for vaccination.

Adjuvant activity of cytokines

The activity of several potent adjuvants, including incomplete Freund's adjuvant, CpG oligodeoxynucleotides, and alum, has been shown to be due at least in part to the induction of cytokines, including type I interferons (IFNs), IFN-gamma, interleukin-2 (IL-2), and IL-12, that play key roles in the regulation of innate and adaptive immunity. The relatively short half-life of recombinant homologues of cytokines has limited their use as vaccine adjuvants. These difficulties have been overcome by encapsulation into liposomes and the use of cytokine expression vectors co-administered with DNA vaccines. Although a number of cytokines including IFN-alpha, IFN-gamma, IL-2, IL-12, IL-15, IL-18, IL-21, GM-CSF, and Flt-3 ligand have been shown to potentiate the immune response to vaccination in various experimental models, the full potential of cytokines as vaccine adjuvants remains to be established.

Humoral and cellular immune responses after influenza vaccination in kidney transplant recipients

It has been speculated that influenza vaccination of renal allograft recipients could be associated with de novo production and/or increased titers of anti-HLA antibodies (HLA-Ab). To directly address this issue, we recruited 66 stable renal transplant recipients and 19 healthy volunteers during the 2005-2006 vaccination campaign. At day 0 and day 30 following vaccination, HLA-Ab were screened and in parallel influenza-specific antibody and T-cell responses were assessed. Humoral postvaccinal responses to A/H1N1 and A/H3N2 strains, but not B strain, were less frequent in transplanted patients than in control subjects. Significant expansion of influenza-specific IFN-gamma-producing T cells was observed at similar frequencies in patients and controls. There was no correlation between cellular and humoral postvaccinal responses. No impact of sex, age or immunosuppressive regimen could be evidenced. Vaccination was not associated with any significant change in preexisting or de novo anti-HLA sensitization. No episode of allograft rejection was recorded in any of the patients. Our results suggest that flu vaccination is safe in stable renal transplanted patients. Larger studies are needed for definitive statistical proof of the safety and effectiveness, with regard to the quality of the immune response, of yearly influenza vaccination in immunosuppressed patients.

Recombinant interferon-alpha2b improves immune response to hepatitis B vaccination in haemodialysis patients: results of a randomised clinical trial

The use of adjuvants capable of improving the deficient immune response to hepatitis B virus (HBV) vaccine in haemodialysis patients is highly needed. Among potential adjuvants, type I interferons deserve a special attention in view of their known effects promoting cellular and humoral immune responses. The aim of the present trial was to evaluate the effects of recombinant interferon-alpha2b (IFN) administered as an adjuvant of HBV vaccine in unvaccinated haemodialysis patients. A significant and early enhancing effect on the antibody response was observed in patients receiving IFN. In addition, a predominance of IgG1 anti-HBs along with a transient normalization of circulating Th1 lymphocytes was only found in patients receiving IFN who achieved an early seroprotection. However, 6 months after the last vaccine dose, no significant differences were observed in the seroprotection rate achieved in patients vaccinated with IFN compared to that in patients receiving HBV vaccine alone. Mild to moderate fever, asthenia, and arthromyalgia were the most common reactions that occurred in vaccinees given IFN. In conclusion, addition of IFN to HBV vaccine, under the conditions used in this trial, is safe and achieves an earlier and higher seroprotection rate improving Th1-dependent immune response in haemodialysis patients.