Immunogenicity of varicella-zoster virus vaccine by different routes of administration: Comparable vaccination efficacy of one-fifth dose intradermal vaccination to conventional subcutaneous vaccination.

BACKGROUND: The live attenuated varicella-zoster virus (VZV) vaccine is used for the prevention of chickenpox and herpes zoster; however, there have been few studies on the immunogenicity of intradermal vaccination. OBJECTIVE: To compare the immunogenicity between subcutaneous and intradermal VZV vaccination. METHODS: Thirty healthy participants aged 50-75 who developed erythema less than 10 mm in diameter in VZV skin test were examined. Thirteen participants received full dose of VZV vaccine subcutaneously and 17 participants received one-fifth dose of vaccine intradermally. Immunogenicity to VZV was determined by VZV skin test reaction, proliferation of VZV-specific memory T cells, levels of VZV-specific serum antibody, and cytokine production from peripheral blood cells. RESULTS: VZV skin test reaction was similar between two groups. VZV-specific memory T cells were significantly increased only in the intradermal injection group. The increase of VZV-specific memory T cells correlated with Th1, Th2 and Th17 cytokines and cytotoxic molecules. No serious adverse events were observed in either group after vaccination. CONCLUSION: Intradermal injection with one-fifth dose VZV vaccine showed a similar or greater effect on VZV-specific cellular immunostimulation than conventional subcutaneous injection. These findings suggest that one-fifth dose intradermal vaccination may have a comparable preventive effect to conventional subcutaneous injection.

Immunogenicity of Quadrivalent Influenza Vaccine for Patients with Inflammatory Bowel Disease Undergoing Immunosuppressive Therapy.

Background and Aims: No reports have described the immunogenicity and boosting effect of the quadrivalent inactivated influenza vaccine (QIV) in adults with inflammatory bowel disease. Methods: Adults with Crohn's disease or ulcerative colitis were randomly assigned to a single vaccination group or booster group, and a QIV was administered subcutaneously. Serum samples were collected before vaccination, 4 weeks after vaccination, and after the influenza season in the single vaccination group. In the booster group, serum samples were taken before vaccination, 4 weeks after the first vaccination, 4 weeks after the second vaccination, and after the influenza season. We measured hemagglutination inhibition antibody (HAI) titer and calculated the geometric mean titer ratio (GMTR), seroprotection rate, and seroconversion rate. Results: In total, 132 patients were enrolled. Twenty-two patients received immunomodulatory monotherapy and 16 received anti-tumor necrosis factor-α (anti-TNF-α) single-agent therapy. Fifteen patients received combination therapy comprising an immunosuppressant and anti-TNF-α agent. Each vaccine strain showed immunogenicity satisfying the European Medicines Agency criteria with a single inoculation. The booster influenza vaccination did not induce additional response. In patients administered infliximab, the seroprotection rate and seroconversion rate tended to be lower in patients who maintained blood concentrations [seroprotection rate: H1N1: OR, 0.37 (95% CI, 0.11-1.21); H3N2: 0.22 (0.07-0.68); seroconversion rate: H1N1: 0.23 (0.06-0.91); H3N2: 0.19 (0.06-0.56)]. Conclusion: Single dose QIV showed sufficient immunogenicity in patients with inflammatory bowel disease, and a boost in immunization by additional vaccination was not obtained. Additionally, immunogenicity was low in patients receiving infliximab therapy.

Safety profile of the varicella vaccine (Oka vaccine strain) based on reported cases from 2005 to 2015 in Japan.

BACKGROUND: As of 2014, routine vaccination strategies in Japan have included the varicella vaccine. Given the widespread use of the vaccine, it is important to investigate the safety profile of the vaccine strain, Oka/Biken varicella, in Japanese patients. METHODS: Reports of adverse events associated with varicella vaccination between 2005 and 2015 were retrospectively reviewed. Virological analysis was performed on clinical specimens collected from some of the reported cases to determine whether the etiological agent was the wild-type or Oka vaccine-strains. RESULTS: There were 351 reports (3.71/100,000 doses) of adverse events during the observation period. Among the 351 reports, there were 88 reports (0.93/100,000 doses) of varicella-like and 66 reports (0.70/100,000 doses) of zoster-like skin rashes. The wild-type strain induced varicella-like skin rashes earlier than the Oka vaccine strain. The Oka vaccine strain induced zoster-like skin rashes in younger patients compared to the wild-type strain. The onset of zoster-like skin rashes after vaccination was earlier in patients vaccinated with the Oka vaccine-type strain. CONCLUSION: The Oka/Biken vaccine is generally safe and well tolerated in Japan. Clinical aspects of adverse reactions caused by the Oka vaccine strain were consistent with previous reports from the United States and Europe.

Deep Sequencing of Distinct Preparations of the Live Attenuated Varicella-Zoster Virus Vaccine Reveals a Conserved Core of Attenuating Single-Nucleotide Polymorphisms.

UNLABELLED: The continued success of the live attenuated varicella-zoster virus vaccine in preventing varicella-zoster and herpes zoster is well documented, as are many of the mutations that contribute to the attenuation of the vOka virus for replication in skin. At least three different preparations of vOka are marketed. Here, we show using deep sequencing of seven batches of vOka vaccine (including ZostaVax, VariVax, VarilRix, and the Oka/Biken working seed) from three different manufacturers (VariVax, GSK, and Biken) that 137 single-nucleotide polymorphism (SNP) mutations are present in all vaccine batches. This includes six sites at which the vaccine allele is fixed or near fixation, which we speculate are likely to be important for attenuation. We also show that despite differences in the vaccine populations between preparations, batch-to-batch variation is minimal, as is the number and frequency of mutations unique to individual batches. This suggests that the vaccine manufacturing processes are not introducing new mutations and that, notwithstanding the mixture of variants present, VZV live vaccines are extremely stable. IMPORTANCE: The continued success of vaccinations to prevent chickenpox and shingles, combined with the extremely low incidence of adverse reactions, indicates the quality of these vaccines. The vaccine itself is comprised of a heterogeneous live attenuated virus population and thus requires deep-sequencing technologies to explore the differences and similarities in the virus populations between different preparations and batches of the vaccines. Our data demonstrate minimal variation between batches, an important safety feature, and provide new insights into the extent of the mutations present in this attenuated virus.

Varicella zoster virus antibody detection: A comparison of four commonly used techniques.

BACKGROUND: Antibody tests for the varicella zoster virus (VZV) include neutralization, fluorescent antibody to membrane antigen (FAMA), immune adherence hemagglutination (IAHA), enzyme immunoassay (EIA), glycoprotein-based enzyme-linked immunosorbent assay (gpELISA), and complement fixation (CF) tests. Of these, FAMA is considered the most sensitive. However, in Japan, the EIA method is most frequently employed. OBJECTIVE: The VZV antibody detection rate of the FAMA, EIA, gpELISA, and IAHA methods was compared. METHODS: Four types of antibody tests were conducted with sera collected from 83 college students. The relationships between two antibody tests were examined using Pearson's correlation coefficients. RESULTS: All 83 subjects were observed to be VZV antibody-positive using the FAMA method. The Pearson correlation coefficients of gpELISA, EIA, and IAHA relative to FAMA were 0.808, 0.782, and 0.356, respectively. The positive agreement rate of IAHA relative to FAMA was 88.0% (73/83), whereas those of gpELISA and EIA were both 97.6% (81/83). Furthermore, EIA showed 100% positive agreement with gpELISA and a high correlation coefficient of 0.911, whereas these values for IAHA compared to gpELISA were much lower (90.1% and 0.530). The calculated Pearson correlation coefficient for comparison of the EIA and IAHA methods was 0.498, with a positive agreement rate of 90.1% (73/81). CONCLUSIONS: The EIA method should be employed in Japan based on the similarity of the positivity between EIA and gpELISA, as it is more available and practical than gpELISA.

Good manufacturing practices production of a purification-free oral cholera vaccine expressed in transgenic rice plants.

KEY MESSAGE: The first Good Manufacturing Practices production of a purification-free rice-based oral cholera vaccine (MucoRice-CTB) from transgenic plants in a closed cultivation system yielded a product meeting regulatory requirements. Despite our knowledge of their advantages, plant-based vaccines remain unavailable for human use in both developing and industrialized countries. A leading, practical obstacle to their widespread use is producing plant-based vaccines that meet governmental regulatory requirements. Here, we report the first production according to current Good Manufacturing Practices of a rice-based vaccine, the cholera vaccine MucoRice-CTB, at an academic institution. To this end, we established specifications and methods for the master seed bank (MSB) of MucoRice-CTB, which was previously generated as a selection-marker-free line, evaluated its propagation, and given that the stored seeds must be renewed periodically. The production of MucoRice-CTB incorporated a closed hydroponic system for cultivating the transgenic plants, to minimize variations in expression and quality during vaccine manufacture. This type of molecular farming factory can be operated year-round, generating three harvests annually, and is cost- and production-effective. Rice was polished to a ratio of 95 % and then powdered to produce the MucoRice-CTB drug substance, and the identity, potency, and safety of the MucoRice-CTB product met pre-established release requirements. The formulation of MucoRice-CTB made by fine-powdering of drug substance and packaged in an aluminum pouch is being evaluated in a physician-initiated phase I study.

Incidences of Herpes Zoster and Postherpetic Neuralgia in Japanese Adults Aged 50 Years and Older From a Community-based Prospective Cohort Study: The SHEZ Study.

BACKGROUND: Many cross-sectional studies have examined the incidences of herpes zoster (HZ) and postherpetic neuralgia (PHN), but prospective studies in Japanese older adults are lacking. Therefore, we conducted a community-based prospective cohort study to determine the incidence in Japanese adults aged ≥50 years. METHODS: We recruited 12 522 participants from Shozu County, Kagawa Prefecture, between December 2008 and November 2009 and followed participants for 3 years. When a subject presented with symptoms suggestive of HZ, they were examined at collaborating medical institutions and cooperated with onset and recovery surveys (eg, measurement of varicella zoster virus-specific immunity and a pain survey). The hazard ratios (HRs) of HZ and PHN according to sex and age were analyzed by Cox regression analysis with a significance level of 5%. RESULTS: The incidence of HZ was 10.9/1000 person-years (men: 8.5/1000 person-years; women: 12.8/1000 person-years) and was significantly higher in women than in men (HR 1.5; 95% confidence interval, 1.2-1.8). The incidence of PHN was 2.1/1000 person-years (men: 1.7/1000 person-years; women: 2.4/1000 person-years), with no significant sex differences. A total of 19% of HZ cases progressed to PHN; no sex-specific difference in the proportion of PHN cases was observed. CONCLUSIONS: We clarified the accurate incidences of HZ and PHN in a population of Japanese older adults. These incidences increased with age. HZ incidence was higher in women than in men, while PHN incidence did not differ markedly between the sexes.

Evaluation of varicella zoster virus-specific cell-mediated immunity by using an interferon-γ enzyme-linked immunosorbent assay.

BACKGROUND: Administration of the varicella vaccine induces both varicella-zoster virus (VZV)-specific humoral and cell-mediated immunity (CMI). OBJECTIVE: To assess VZV-CMI, we developed an interferon γ enzyme-linked immunosorbent assay (IFN-γ ELISA) that measures the quantity of total IFN-γ in culture supernatants of human peripheral blood mononuclear cells. STUDY DESIGN: We evaluated this method by comparing the pre- and post-vaccination immune response in peripheral blood mononuclear cells of 30 healthy children who were administered an initial varicella vaccination at Konan Kosei hospital. RESULTS: IFN-γ ELISA showed well-validated results; CMI was not detectable pre-immunization but became detectable post-immunization. Seroconversion was detected in 92.6% of subjects by the immune adherence hemagglutination test; however, half of the subjects did not display an increase in CMI levels. We also compared the incidence of breakthrough varicella and herpes zoster development between CMI post-positive and post-negative vaccinees at 1-2years after the last VZV vaccination. Eight subjects had a history of varicella or herpes zoster exposure post-VZV vaccination. Two of them with post-negative CMI contracted breakthrough varicella 15-16months after the last vaccination, even though they had sufficient VZV-specific antibody levels to be considered seropositive and seroprotected. Conversely, the others with post-positive CMI did not contract breakthrough varicella, despite experiencing extensive VZV exposure through casual contact with playmates and family. CONCLUSIONS: The CMI data generated by this IFN-γ ELISA may accurately reflect real-world immune status, and CMI may be closely related to immunoprotection against breakthrough varicella development.

A recombinant varicella vaccine harboring a respiratory syncytial virus gene induces humoral immunity.

The varicella-zoster virus (VZV) Oka vaccine strain (vOka) is highly efficient and causes few adverse events; therefore, it is used worldwide. We previously constructed recombinant vOka (rvOka) harboring the mumps virus gene. Immunizing guinea pigs with rvOka induced the production of neutralizing antibodies against the mumps virus and VZV. Here, we constructed recombinant vOka viruses containing either the respiratory syncytial virus (RSV) subgroup A fusion glycoprotein (RSV A-F) gene or RSV subgroup B fusion glycoprotein (RSV B-F) gene (rvOka-RSV A-F or rvOka-RSV B-F). Indirect immunofluorescence and Western blot analyses confirmed the expression of each recombinant RSV protein in virus-infected cells. Immunizing guinea pigs with rvOka-RSV A-F or rvOka-RSV B-F led to the induction of antibodies against RSV proteins. These results suggest that the current varicella vaccine genome can be used to generate custom-made vaccine vectors to develop the next generation of live vaccines.

VZV skin-test reaction, but not antibody, is an important predictive factor for postherpetic neuralgia.

BACKGROUND: The decline of cell-mediated immunity (CMI) is thought to be related to the risk of postherpetic neuralgia (PHN) as well as herpes zoster (HZ). However, the relationship between immunological condition and the incidence of PHN is still unclear. OBJECTIVE: We conducted a large-scale prospective cohort study to clarify the relationship between immunological factors for varicella-zoster virus (VZV) and the incidence of PHN. METHODS: We carried out a cohort study on VZV immunity in a population living on an island cluster, Shozu County in Japan, and examined the people who developed HZ during a follow-up period of 3 years, with a focus on the relationship between cell-mediated and humoral immunity and the incidence of PHN. A total of 12,522 people over the age of 50 were enrolled in this study, and 401 registrants were diagnosed with HZ, including 79 PHN cases. We evaluated anatomical location and severity of skin lesion, acute pain severity, presence or absence of abnormal sensations, CMI assessed by VZV skin test, and VZV-specific antibody titer measured by serological tests. RESULTS: The incidence of PHN was significantly associated with a weak response to the VZV skin test, as well as facial or lumbosacral localization of skin rash, severe skin lesion, severe acute pain, and presence of abnormal sensations, but not related to VZV-specific antibody titer. CONCLUSION: The incidence of PHN is significantly associated with the decline of VZV-specific CMI, but not related to VZV-specific humoral immunity.

A Lipopolysaccharide from Pantoea Agglomerans Is a Promising Adjuvant for Sublingual Vaccines to Induce Systemic and Mucosal Immune Responses in Mice via TLR4 Pathway.

A lipopolysaccharide from Pantoea agglomerans (LPSpa) has been applied to various fields for human use as a Toll-like receptor 4 ligand and its safety has been confirmed. Here, we showed for the first time the application of LPSpa as an effective mucosal adjuvant for activating vaccine-induced antigen specific immune responses. Mice sublingually immunized with influenza vaccine (HA split vaccine) with LPSpa induced both HA-specific IgG (systemic) and IgA (mucosal) antibody responses, which led to a significant increase in survival rate against lethal influenza virus challenge compared with subcutaneous vaccination. After sublingual administration of ovalbumin with LPSpa, ovalbumin-specific mucosal IgA responses were induced at both mucosal surfaces close to the immunized site and at remote mucosal surfaces. Sublingual administration of LPSpa evoked local antigen-uptake by dendritic cells in cervical lymph nodes. LPSpa induced cytokine production and the maturation and proliferation of innate immune cells via Toll-like receptor 4 in dendritic cells. Collectively, these results suggest that LPSpa can be used as an effective mucosal adjuvant to stimulate and activate local innate immune cells to improve and enhance mucosal vaccine potency against various pathogens.

Varicella-zoster virus ORF49 functions in the efficient production of progeny virus through its interaction with essential tegument protein ORF44.

The ORF49 tegument protein of varicella-zoster virus (VZV) is one of the core gene products that is conserved among herpesvirus family members. Although ORF49 is known to be a cell-tropic factor, its detailed functions remain elusive. ORF44 is another core gene product reported to be essential, although its characterization and detailed functional analysis have not been reported. These two core gene products form a complex in other herpesviruses beyond the host species and herpesvirus subfamilies. Here, we show that complex formation between ORF44 and ORF49 is conserved in VZV. We serendipitously found that binding is eliminated by an amino acid substitution at position 129 (phenylalanine 129), and four amino acids in the carboxyl-terminal half of the acidic cluster in ORF49 (i.e., aspartate-phenylalanine-aspartate-glutamate from positions 41 to 44 [41DFDE44]) were identified as its binding motif. Alanine substitutions in each domain rendered the ORF44F129A mutation lethal for VZV, similar to deletion of the entire ORF44. The phenotype of the ORF49-41AAAA44 mutation was comparable to that of the ORF49-defective virus, including small-plaque formation, impaired growth, and low infectious virus production. These results suggest that the interaction between ORF44 and ORF49 is essential for their role in VZV infection and that ORF49 is required for the efficient production of infectious progeny virus mediated by the conserved interaction between the two proteins.

Novel polyvalent live vaccine against varicella-zoster and mumps virus infections.

The varicella-zoster virus (VZV) Oka vaccine strain (vOka) is a highly immunogenic and safe live vaccine that has long been used worldwide. Because its genome is large, making it suitable for inserting foreign genes, vOka is considered a candidate vector for novel polyvalent vaccines. Previously, a recombinant vOka, rvOka-HN, that expresses mumps virus (MuV) hemagglutinin-neuraminidase (HN) was generated by the present team. rvOka-HN induces production of neutralizing antibodies against MuV in guinea pigs. MuV also expresses fusion (F) protein, which is important for inducing neutralizing antibodies, in its viral envelope. To induce a more robust immune response against MuV than that obtained with rvOka-HN, here an rvOka expressing both HN and F (rvOka-HN-F) was generated. However, co-expression of HN and F caused the infected cells to form syncytia, which reduced virus titers. To reduce the amount of cell fusion, an rvOka expressing HN and a mutant F, F(S195Y) were generated. Almost no syncytia formed among the rvOka-HN-F(S195Y)-infected cells and the growth of rvOka-HN-F(S195Y) was similar to that of the original vOka clone. Moreover, replacement of serine 195 with tyrosine had no effect on the immunogenicity of F in mice and guinea pigs. Although obvious augmentation of neutralizing antibody production was not observed after adding F protein to vOka-HN, the anti-F antibodies did have neutralizing activity. These data suggest that F protein contributes to induction of immune protection against MuV. Therefore this recombinant virus is a promising candidate vaccine for polyvalent protection against both VZV and MuV.

An inverse correlation of VZV skin-test reaction, but not antibody, with severity of herpes zoster skin symptoms and zoster-associated pain.

BACKGROUND: Cell-mediated immunity (CMI) has been considered to be related to the development of herpes zoster (HZ). However, there have been no large-scale prospective studies on the relationship between VZV-specific CMI and severity of HZ. OBJECTIVE: We carried out a large-scale prospective cohort study to clarify the relationship between immunological factors for varicella-zoster virus (VZV) and the clinical severity of HZ. METHODS: We carried out a cohort study on VZV immunity in a population living on an island cluster, Shozu County in Japan, and examined the people who developed HZ during a median follow-up period of 2 years, with a focus on the relationship between cell-mediated and humoral immunity and the severity of skin lesions and zoster-associated pain. A total of 12,522 people over the age of 50 were enrolled in this study, and 258 registrants were diagnosed as HZ. CMI was measured by VZV skin test, and humoral immunity was assessed with serological tests (neutralization test, immunoadherence hemagglutination test, and gpELISA test) for VZV-specific antibodies. RESULTS: CMI to VZV assessed by VZV skin test showed a significant inverse relationship to the severity of HZ skin lesions, and also to the severity of acute and subacute pain. Furthermore, weak response to the VZV skin test was associated with a high risk of post-herpetic neuralgia. In contrast, VZV-specific antibody titer was not associated with the severity of skin lesions and zoster-associated pain. CONCLUSION: VZV-specific CMI, but not humoral immunity, may play a key role in controlling the severity of HZ skin lesions and zoster-associated pain.

Intranasal immunization with a formalin-inactivated human influenza A virus whole-virion vaccine alone and intranasal immunization with a split-virion vaccine with mucosal adjuvants show similar levels of cross-protection.

The antigenicity of seasonal human influenza virus changes continuously; thus, a cross-protective influenza vaccine design needs to be established. Intranasal immunization with an influenza split-virion (SV) vaccine and a mucosal adjuvant induces cross-protection; however, no mucosal adjuvant has been assessed clinically. Formalin-inactivated intact human and avian viruses alone (without adjuvant) induce cross-protection against the highly pathogenic H5N1 avian influenza virus. However, it is unknown whether seasonal human influenza formalin-inactivated whole-virion (WV) vaccine alone induces cross-protection against strains within a subtype or in a different subtype of human influenza virus. Furthermore, there are few reports comparing the cross-protective efficacy of the WV vaccine and SV vaccine-mucosal adjuvant mixtures. Here, we found that the intranasal human influenza WV vaccine alone induced both the innate immune response and acquired immune response, resulting in cross-protection against drift variants within a subtype of human influenza virus. The cross-protective efficacy conferred by the WV vaccine in intranasally immunized mice was almost the same as that conferred by a mixture of SV vaccine and adjuvants. The level of cross-protective efficacy was correlated with the cross-reactive neutralizing antibody titer in the nasal wash and bronchoalveolar fluids. However, neither the SV vaccine with adjuvant nor the WV vaccine induced cross-reactive virus-specific cytotoxic T-lymphocyte activity. These results suggest that the intranasal human WV vaccine injection alone is effective against variants within a virus subtype, mainly through a humoral immune response, and that the cross-protection elicited by the WV vaccine and the SV vaccine plus mucosal adjuvants is similar.

The Shozu Herpes Zoster (SHEZ) study: rationale, design, and description of a prospective cohort study.

BACKGROUND: The incidence and risk factors for herpes zoster have been studied in cross-sectional and cohort studies, although most such studies have been conducted in Western countries. Evidence from Asian populations is limited, and no cohort study has been conducted in Asia. We are conducting a 3-year prospective cohort study in Shozu County in Kagawa Prefecture, Japan to determine the incidence and predictive and immunologic factors for herpes zoster among Japanese. METHODS: The participants are followed for 3 years, and a telephone survey is conducted every 4 weeks. The participants were assigned to 1 of 3 studies. Participants in study A gave information on past history of herpes zoster and completed health questionnaires. Study B participants additionally underwent varicella-zoster virus (VZV) skin testing, and study C participants additionally underwent blood testing. If the participants develop herpes zoster, we evaluate clinical symptoms, measure cell-mediated immunity and humoral immunity using venous blood sampling, photograph skin areas with rash, conduct virus identification testing by polymerase chain reaction (PCR) and virus isolation from crust sampling, and evaluate postherpetic pain. RESULTS: We recruited 12 522 participants aged 50 years or older in Shozu County from December 2009 through November 2010. The participation rate was 65.7% of the target population. CONCLUSIONS: The present study is likely to provide valuable data on the incidence and predictive and immunologic factors for herpes zoster in a defined community-based population of Japanese.

Superior immunogenicity of a freeze-dried, cell culture-derived Japanese encephalitis vaccine (inactivated).

Japanese encephalitis is an infectious disease caused by the Japanese encephalitis virus, which is widespread throughout Asia. The worldwide incidence is 50,000 cases per year. There is no specific treatment available, but inactivated mouse brain-derived vaccine was used from the 1950s to prevent infection. However, quality control of mouse brain-derived vaccines is difficult, and therefore a new freeze-dried, cell culture-derived Japanese encephalitis vaccine (inactivated) (JEBIK V; development code: BK-VJE) was developed. In this paper, we report an analysis of neutralizing antibody titers in vaccinated subjects enrolled in clinical study of BK-VJE at various doses, and study of BK-VJE with the mouse brain-derived vaccine as a control. The results show that BK-VJE has superior immunogenicity compared to mouse brain-derived vaccine.

Characterization of neutralizing antibodies in adults after intranasal vaccination with an inactivated influenza vaccine.

The levels and properties of neutralizing antibodies in nasal wash and serum collected from five healthy adults were examined after intranasal administration of an A/Uruguay/716/2007 (H3N2) split vaccine (45 µg hemagglutinin (HA) per dose; five doses, with an interval of 3 weeks between each dose). Prior to the assays, nasal wash samples were concentrated so that the total amount of antibodies was equivalent to about 1/10 of that found in the natural nasal mucus. Vaccination induced virus-specific neutralizing antibody responses, which increased with the number of vaccine doses given. Neutralizing antibodies were produced more efficiently in the nasal passages than in the serum: A ≥4-fold increase in nasal neutralization titres was observed after the second vaccination in four out of five subjects, whereas a rise in serum neutralization titres was observed only after the fifth vaccination. Nasal and serum neutralizing antibodies were mainly found in the polymeric IgA and monomeric IgG fractions, respectively, after gel filtration. Taken together, these results suggest that intranasal administration of an inactivated split vaccine induces high levels of nasal neutralizing antibodies (primarily polymeric IgA) and low levels of serum neutralizing antibodies (primarily monomeric IgG).

Anti-influenza activity of marchantins, macrocyclic bisbibenzyls contained in liverworts.

The H1N1 influenza A virus of swine-origin caused pandemics throughout the world in 2009 and the highly pathogenic H5N1 avian influenza virus has also caused epidemics in Southeast Asia in recent years. The threat of influenza A thus remains a serious global health issue and novel drugs that target these viruses are highly desirable. Influenza A possesses an endonuclease within its RNA polymerase which comprises PA, PB1 and PB2 subunits. To identify potential new anti-influenza compounds in our current study, we screened 33 different types of phytochemicals using a PA endonuclease inhibition assay in vitro and an anti-influenza A virus assay. The marchantins are macrocyclic bisbibenzyls found in liverworts, and plagiochin A and perrottetin F are marchantin-related phytochemicals. We found from our screen that marchantin A, B, E, plagiochin A and perrottetin F inhibit influenza PA endonuclease activity in vitro. These compounds have a 3,4-dihydroxyphenethyl group in common, indicating the importance of this moiety for the inhibition of PA endonuclease. Docking simulations of marchantin E with PA endonuclease suggest a putative "fitting and chelating model" as the mechanism underlying PA endonuclease inhibition. The docking amino acids are well conserved between influenza A and B. In a cultured cell system, marchantin E was further found to inhibit the growth of both H3N2 and H1N1 influenza A viruses, and marchantin A, E and perrotein F showed inhibitory properties towards the growth of influenza B. These marchantins also decreased the viral infectivity titer, with marchantin E showing the strongest activity in this assay. We additionally identified a chemical group that is conserved among different anti-influenza chemicals including marchantins, green tea catechins and dihydroxy phenethylphenylphthalimides. Our present results indicate that marchantins are candidate anti-influenza drugs and demonstrate the utility of the PA endonuclease assay in the screening of phytochemicals for anti-influenza characteristics.

Purification and concentration of non-infectious West Nile virus-like particles and infectious virions using a pseudo-affinity Cellufine Sulfate column.

Affinity column chromatography is a promising method for the purification of flavivirus particles that can supplement or potentially replace diafiltration and sucrose density centrifugation. In this study, the purification of West Nile Virus (WNV) antigens via Cellufine Sulfate column chromatography was examined. Virus-like particles (VLPs) produced by the expression of the prM and E genes were separated from most of the contaminant proteins with 0.2-0.4M NaCl, but still retained their spherical forms and immunogenicity in mice. The column, with a 1 mL bed-volume, concentrated WN-VLPs a minimum of 15 fold from culture supernatants. A heparin analogue, suramin, competitively eluted WN-VLPs, but sulphated polysaccharides, such as heparin, heparin sulfate and dextran sulfate, did not. Furthermore, 2.4 × 109 plaque forming units of WNV and 196 µg of the viral antigens were recovered from 60 mL of infected culture medium at high yields (93% and 96%, respectively). These results indicate that, in addition to conventional methods, Cellufine Sulfate column chromatography is an effective preparation technique for WNV particulate antigens that does not impair the antigen virological characteristics.