Development and approval of live attenuated influenza vaccines based on Russian master donor viruses: Process challenges and success stories

Influenza is a viral infection that affects much of the global population each year. Vaccination remains the most effective tool for preventing the disease. Live attenuated influenza vaccine (LAIV) has been used since the 1950s to protect humans against seasonal influenza. LAIVs developed by the Institute of Experimental Medicine (IEM), Saint Petersburg, Russia, have been successfully used in Russia since 1987.In 2006, the World Health Organization (WHO) announced a Global action plan for influenza vaccines (GAP). WHO, recognizing potential advantages of LAIV over the inactivated influenza vaccine in a pandemic situation, included LAIV in the GAP.BioDiem Ltd., a vaccine development company based in Melbourne, Australia which held the rights for the Russian LAIV, licensed this technology to WHO in 2009. WHO was permitted to grant sub-licenses to vaccine manufacturers in newly industrialized and developing countries to use the Russian LAIV for the development, manufacture, use and sale of pandemic and seasonal LAIVs. To date, WHO has granted sub-licenses to vaccine manufacturers in China (Changchun BCHT Biotechnology Co., Ltd.), India (Serum Institute of India Pvt. Ltd.) and Thailand (Government Pharmaceutical Organization). In parallel, in 2009, IEM signed an agreement with WHO, under which IEM committed to supply pandemic and seasonal candidate vaccine viruses to the sub-licensees.This paper describes the progress made by collaborators from China, India, Russia and Thailand in developing preventive measures, including LAIV against pandemic influenza.     

Vaccination evokes gender-dependent protection against tularemia infection in C57BL/6Tac mice

Francisella tularensis (Ft) is a Category A biothreat agent for which there currently is no FDA-approved vaccine. Thus, there is a substantial effort underway to develop an effective tularemia vaccine. While it is well established that gender can significantly impact susceptibility to primary infection, the impact of gender on vaccine efficacy is not well established. Thus, development of a successful vaccine against tularemia will require an understanding of the impact gender has on vaccine-induced protection against this organism. In this study, a role for gender in vaccine-induced protection following Ft challenge is identified for the first time. In the present study, mucosal vaccination with inactivated Ft (iFt) LVS elicited gender-based protection in C57BL/6Tac mice against respiratory challenge with Ft LVS. Specifically, vaccinated male mice were more susceptible to subsequent Ft LVS challenge. This increased susceptibility in male mice correlated with increased bacterial burden, increased tissue inflammation, and increased proinflammatory cytokine production late in post-challenge infection. In contrast, improved survival of iFt-vaccinated female mice correlated with reduced bacterial burden and enhanced levels of Ft-specific Abs in serum and broncho-alveolar lavage (BAL) fluid post-challenge. Furthermore, vaccination with a live attenuated vaccine consisting of an Ft LVS superoxide dismutase (SodB) mutant, which has proven efficacious against the highly virulent Ft SchuS4 strain, demonstrated similar gender bias in protection post-Ft SchuS4 challenge. Of particular significance is the fact that these are the first studies to demonstrate that gender differences impact disease outcome in the case of lethal respiratory tularemia following mucosal vaccination. In addition, these studies further emphasize the fact that gender differences must be a serious consideration in any future tularemia vaccine development studies.     

The impact of frost-damage on the quality and quantity of the secreted antigen-specific IgG repertoire

Freezing of alum-based vaccines drastically alters their colloidal composition and leads to irreversible cluster formation. The loss of stability is well described, but the impact of frost damage on the functionality of the induced and secreted antibody repertoire has not been studied in detail. We therefore applied our single-cell measurement platform to extract the frequencies of Immunoglobulin G-secreting cells in combination with individual secretion rates and affinities. We showed that, frost-damaged or not, the tested vaccine was able to generate similar frequencies of total and antigen-affine IgG-secreting cells. Additionally, the frost-damaged vaccine stimulated a similar T-cell cytokine secretion pattern when compared to the regularly stored vaccine. However, frost-damaged vaccines induced no efficient affinity maturation and a complete collapse of the affinity distribution was observed. This study unveiled the impact of frost-damage to alum-based vaccines on the induced secreted antibody repertoire, and illustrated the power of functional single-antibody analysis.     

Recurrent respiratory papillomatosis in northern Sweden: Clinical characteristics and practical guidance

Conclusion: Recurrent respiratory papillomatosis (RRP) patients with high surgical treatment frequency (≥ 1/year, HF) were significantly younger and had a more widespread laryngeal disease compared to a low frequency treated group (< 1 treatment/year, LF). This study confirms the existence of a clinical RRP group, not primarily related to HPV sub-type, but more care-intensive and in need of more vigilant follow-up. Objectives: RRP is associated with high morbidity due to its influence on breathing and voice. The purpose of this study was to characterize RRP patients in northern Sweden and investigate possible predictor factors affecting therapeutic needs. Method: Patients from the regional referral area (northern Sweden) were categorized for age, disease duration, juvenile or adult onset, profile of disease development, number of surgical sessions in relation to disease duration, laryngeal deposition of papilloma, gender, and HPV sub-types, in order to identify patients with increased need for frequent surgical treatment. Results: The median age of the RRP patients (n = 48) was 44.5 years; 34 (71%) were males and 14 (29%) females, most were infected with HPV 6. Patients with high surgical treatment frequency/year were significantly younger and showed more widespread papillomatous vegetation in the larynx, compared to the low frequency treated group.     

Near-infrared fluorescence imaging improves the nodal yield in neck dissection in oral cavity cancer – A randomized study

IntroductionLymph node yield (LNY) in neck dissection has been identified as a prognostic factor in oral cavity cancer. The purpose of this study was to investigate the impact of additional use of optical imaging on LNY in therapeutic ND in oral cancer.MethodsConsecutive patients with oral squamous cell carcinoma with clinical neck metastasis planned for primary tumor resection were randomized to conventional neck dissection or near-infrared fluorescence (NIRF)-guided neck dissection, respectively. In the intervention group, patients were injected with ICG-Nanocoll prior to surgery. Intraoperatively, an optical hand-held camera system was used for lymph node identification. Also, NIRF imaging of the neck specimen was performed, and optical signals were pinned with needle markings to guide the pathological examination. The endpoint of the study was LNY per neck side in levels Ib-III.Results31 patients were included with 18 neck sides in the control group and 18 neck sides in the intervention group for evaluation. During NIRF-guided ND, individual lymph nodes could be identified by a bright fluorescent signal and individual tumor-related drainage patterns could be observed in the neck. The LNY in the intervention group was significantly higher compared to the control group (p = 0.032) with a mean of 24 LN (range: 12–33 LN in levels Ib-III compared to 18 LN (range: 10–36 LN) in the control group, respectively.ConclusionsNIRF-guided ND significantly improved the nodal yield compared to the control group. Intraoperative real-time optical imaging enabled direct visualization of tumor-related drainage patterns within the neck lymphatics.     

Immunization with PhtD truncated fragments reduces nasopharyngeal colonization by Streptococcus pneumoniae

Despite the undeniable success of polysaccharide vaccines against Streptococcus pneumoniae infections, there is a consensus on the scientific field that this approach should be revised in order to overpass the problems related with these formulations, such as serotype replacement and high production costs. The study of conserved pneumococcal proteins or its truncated fragments has emerged as a serotype independent alternative. In this work, we have characterized the immune response elicited by systemic immunization of mice with the Histidine triad protein D (PhtD) and its’ amino and carboxyl terminal fragments. The proteins were shown to be immunogenic and protective against pneumococcal colonization, with increased IL-17 production, and induction of antibodies able to limit pneumococcal adhesion to human respiratory cells. Antiserum against PhtD_Nter, but not C_ter or PhtD, promoted an increase in bacterial phagocytosis in vitro. Interestingly, antibodies against the PhtD_Nter displayed cross-reactivity with two other pneumococcal proteins, PspA and PspC, due to sequence similarities in the proline rich region of the molecules. On a whole, our results support the inclusion of PhtD, and more specifically, its N-terminal fragment, in a multicomponent serotype independent vaccine.     

Durability of humoral immune responses to rubella following MMR vaccination

BackgroundWhile administration of the measles-mumps-rubella (MMR-II®) vaccine has been effective at preventing rubella infection in the United States, the durability of humoral immunity to the rubella component of MMR vaccine has not been widely studied among older adolescents and adults.MethodsIn this longitudinal study, we sought to assess the durability of rubella virus (RV)-specific humoral immunity in a healthy population (n = 98) of adolescents and young adults at two timepoints: ~7 and ~17 years after two doses of MMR-II® vaccination. Levels of circulating antibodies specific to RV were measured by ELISA and an immune-colorimetric neutralization assay. RV-specific memory B cell responses were also measured by ELISpot.ResultsRubella-specific IgG antibody titers, neutralizing antibody titers, and memory B cell responses declined with increasing time since vaccination; however, these decreases were relatively moderate. Memory B cell responses exhibited a greater decline in men compared to women.ConclusionsCollectively, rubella-specific humoral immunity declines following vaccination, although subjects’ antibody titers remain well above the currently recognized threshold for protective immunity. Clinical correlates of protection based on neutralizing antibody titer and memory B cell ELISpot response should be defined.     

Evaluation of protection induced by a dengue virus serotype 2 envelope domain III protein scaffold/DNA vaccine in non-human primates

We describe the preclinical development of a dengue virus vaccine targeting the dengue virus serotype 2 (DENV2) envelope domain III (EDIII). This study provides proof-of-principle that a dengue EDIII protein scaffold/DNA vaccine can protect against dengue challenge. The dengue vaccine (EDIII-E2) is composed of both a protein particle and a DNA expression plasmid delivered simultaneously via intramuscular injection (protein) and gene gun (DNA) into rhesus macaques. The protein component can contain a maximum of 60 copies of EDIII presented on a multimeric scaffold of Geobacillus stearothermophilus E2 proteins. The DNA component is composed of the EDIII portion of the envelope gene cloned into an expression plasmid. The EDIII-E2 vaccine elicited robust antibody responses to DENV2, with neutralizing antibody responses detectable following the first boost and reaching titers of greater than 1:100,000 following the second and final boost. Vaccinated and naïve groups of macaques were challenged with DENV2. All vaccinated macaques were protected from detectable viremia by infectious assay, while naïve animals had detectable viremia for 2–7 days post-challenge. All naïve macaques had detectable viral RNA from day 2–10 post-challenge. In the EDIII-E2 group, three macaques were negative for viral RNA and three were found to have detectable viral RNA post challenge. Viremia onset was delayed and the duration was shortened relative to naïve controls. The presence of viral RNA post-challenge corresponded to a 10–30-fold boost in neutralization titers 28 days post challenge, whereas no boost was observed in the fully protected animals. Based on these results, we determine that pre-challenge 50% neutralization titers of >1:6000 correlated with sterilizing protection against DENV2 challenge in EDIII-E2 vaccinated macaques. Identification of the critical correlate of protection for the EDIII-E2 platform in the robust non-human primate model lays the groundwork for further development of a tetravalent EDIII-E2 dengue vaccine.     

Influenza vaccination and the endurance against air pollution among elderly with acute coronary syndrome

ObjectiveAir pollution, weather condition and influenza are known risk factors of acute coronary syndrome (ACS) among elderly people. The influenza vaccine (IV) has been shown to reduce major cardiovascular events. The purpose of this study was to compare resistance to air pollution and weather factors causing ACS between vaccinated and less-vaccinated elderly people.MethodsA case–crossover design was applied to 1835 elderly ACS patients who were obtained from the 1-million sample of Taiwan National Health Insurance Research Data with inclusion criteria: (1) the first diagnosis of ACS was in cold season and at age 68 or more, (2) had received the free IV program at least once during the period 3 years before the ACS. They were stratified into two groups: 707 had received flu vaccinations for all the 3 years and the remaining 1128 had not. The measurements of air pollutants, temperature, and humidity corresponding to each of the 3 days prior to the ACS diagnosis date were retrieved from the data banks of the Taiwan Environmental Protection Administration and Central Weather Bureau.FindingsIncreases in air pollution concentrations of CO, NO₂, PM₁₀ or PM_2.5 and decreases in temperature significantly influenced the risk of ACS for the non-continuously vaccinated elderly population; however, less significant effects were observed for the continuously vaccinated population.ConclusionConsecutive influenza vaccination may potentially offer resistance against the detrimental effects of air pollution and changes in temperature in frail elderly adults with ACS. Future studies are needed to directly assess the interaction effect between the vaccination and environmental factors on ACS.     

Immune responses against hepatitis C virus genotype 3a virus-like particles in mice: A novel VLP prime-adenovirus boost strategy

Chronic hepatitis C virus (HCV) infection represents a major health threat to global population. In India, approximately 15–20% of cases of chronic liver diseases are caused by HCV infection. Although, new drug treatments hold great promise for HCV eradication in infected individuals, the treatments are highly expensive. A vaccine for preventing or treating HCV infection would be of great value, particularly in developing countries. Several preclinical trials of virus-like particle (VLP) based vaccine strategies are in progress throughout the world. Previously, using baculovirus based system, we have reported the production of hepatitis C virus-like particles (HCV-LPs) encoding structural proteins for genotype 3a, which is prevalent in India. In the present study, we have generated HCV-LPs using adenovirus based system and tried different immunization strategies by using combinations of both kinds of HCV-LPs with other genotype 3a-based immunogens. HCV-LPs and peptides based ELISAs were used to evaluate antibody responses generated by these combinations. Cell-mediated immune responses were measured by using T-cell proliferation assay and intracellular cytokine staining. We observed that administration of recombinant adenoviruses expressing HCV structural proteins as final booster enhances both antibody as well as T-cell responses. Additionally, reduction of binding of VLP and JFH1 virus to human hepatocellular carcinoma cells demonstrated the presence of neutralizing antibodies in immunized sera. Taken together, our results suggest that the combined regimen of VLP followed by recombinant adenovirus could more effectively inhibit HCV infection, endorsing the novel vaccine strategy.