Development and Assessment of Two Highly Pathogenic Avian Influenza(HPAI) H5N6 Candidate Vaccine Viruses for Pandemic Preparedness

Objective In China, 24 cases of human infection with highly pathogenic avian influenza(HPAI) H5 N6 virus have been confirmed since the first confirmed case in 2014. Therefore, we developed and assessed two H5 N6 candidate vaccine viruses(CVVs).Methods In accordance with the World Health Organization(WHO) recommendations, we constructed two reassortant viruses using reverse genetics(RG) technology to match the two different epidemic H5 N6 viruses. We performed complete genome sequencing to determine the genetic stability. We assessed the growth ability of the studied viruses in MDCK cells and conducted a hemagglutination inhibition assay to analyze their antigenicity. Pathogenicity attenuation was also evaluated in vitro and in vivo.Results The results showed that no mutations occurred in hemagglutinin or neuraminidase, and both CVVs retained their original antigenicity. The replication capacity of the two CVVs reached a level similar to that of A/Puerto Rico/8/34 in MDCK cells. The two CVVs showed low pathogenicity in vitro and in vivo, which are in line with the WHO requirements for CVVs.Conclusion We obtained two genetically stable CVVs of HPAI H5N6 with high growth characteristics,which may aid in our preparedness for a potential H5N6 pandemic.

Testing for hepatitis B virus alone does not increase vaccine coverage in non-immunized persons

AIM To determine whether hepatitis B virus(HBV)-testing could serve as a gateway to vaccinate non-immunized individuals in a low-prevalent country.METHODS Non-immunized subjects participating in a multi-center, HBV-testing campaign in Paris, France were identified and contacted via telephone 3-9 mo after testing in order to determine vaccination status. Vaccination coverage was evaluated in per-protocol(for all respondents) and intent-to-treat analysis(assuming all non-responders did not vaccinate).RESULTS In total, 1215/4924(24.7%) enrolled subjects with complete HBV serology were identified as nonimmunized and eligible for analysis. There were 99/902 successfully contacted subjects who had initiated HBV vaccination after screening: per-protocol, 11.0%(95%CI: 9.0-13.2); intent-to-treat, 8.2%(95%CI: 6.7-9.8). In multivariable analysis, vaccination was more likely to be initiated in individuals originating from moderate or high HBV-endemic countries(P < 0.001), patients with limited healthcare coverage(P = 0.01) and men who have sex with men(P = 0.02). When asked about the reasons for not initiating HBV vaccination, the most frequent response was "will be vaccinated later"(33.4%), followed by "did not want to vaccinate"(29.8%), and "vaccination was not proposed by the physician"(21.5%). Sub-group analysis indicated a stark contrast in vaccination coverage across centers, ranging from 0%-56%.CONCLUSION HBV-vaccination after HBV screening was very low in this study, which appeared largely attributed to physician-patient motivation towards vaccination. Increased vaccination coverage might be achieved by emphasizing its need at the organizational level.

Elicitation of strong immune responses by a DNA vaccine expressing a secreted form of hepatitis C virus envelope protein E2 in murine and porcine animal models

AIM： To characterize the immunogenicity of a hepatitis C virus （HCV） E2 DNA vaccine alone or with a protein vaccine boost in murine and porcine animal models. METHODS： A DNA vaccine expressing a secreted form of HCV E2 protein was constructed and used to vaccinate mice and piglets with or without boosting with a recombinant E2 protein vaccine formulated with CpG ODN and 10% Emulsigen. The immunogenicity of HCV E2 vaccines was analyzed by ELISA for antibody responses, MTT assay for lymphocyte proliferation, ELISPOT for the number of interferon-γ secreting cells, and cytotoxic T lymphocyte assays. RESULTS： Intradermal injection of E2 DNA vaccine induced strong Th1-1ike immune responses in mice. In piglets, E2 DNA vaccine elicited moderate and more balanced immune responses. A DNA vaccine prime and protein boost vaccination strategy induced significantly higher E2-specific antibody levels and shifted the immune response towards Th2-1ike ones in piglets. CONCLUSION： A DNA vaccine expressing a secreted form of HCV E2 protein elicited E2-specific immune responses in mice and piglets. Recombinant E2 protein vaccination following DNA immunization significantly increased the antibody response in piglets. These HCV E2 vaccines may represent promising hepatitis C vaccine candidates for further investigations.

DNA vaccine expressing herpes simplex virus 1 glycoprotein C and D protects mice against herpes simplex keratitis

AIM： To investigate whether DNA vaccine encoding herpes simplex virus 1（HSV-1） glycoprotein C（g C） and glycoprotein D（g D） will achieve better protective effect against herpes simplex keratitis（HSK） than DNA vaccine encoding gD alone. METHODS： DNA vaccine expressing gD or gC combined g D（g D.g C） were constructed and carried by chitosan nanoparticle. The expression of fusion protein gD and gC were detected in DNA/nanoparticle transfected 293 T cells by Western-blot. For immunization, mice were inoculated with DNA/nanoparticle for 3 times with 2 wk interval, and two weeks after the final immunization, the specific immune responses and clinical degrees of primary HSK were evaluated. RESULTS： Fusion protein g D.g C could be expressed successfully in cultured 293 T cells. And, p RSC-g C.g DIL21 DNA/chitosan nanoparticle could effectively elicit strongest humoral and cellular immune response in primary HSK mice evidenced by higher levels of specific neutralizing antibody and s Ig A production, enhanced cytotoxicities of splenocytes and nature killer cells（NK）,when compared with those of gD alone or mocked vaccine immunized mice. As a result, gC-based vaccine immunized mice showed least HSK disease. CONCLUSION： gC-based DNA vaccine could effectively prevent the progress of primary HSK, suggesting that this DNA vaccine could be a promising vaccine for HSK treatment in the future.

Expression of Porcine Interleukin-2 and Porcine Interleukin-6 and Their Adjuvant Effects on Gene Deleted Vaccine of Pseudorabies Virus(TK^-/gG^-/LacZ^+)

Porcine interleukin-2 and porcine interleukin-6 cDNA sequences were cloned into the expressing vectors pET-28a and pGEX-KG respectively. They were expressed in E. coli BL21(DE3)with high-level production. The gene deleted vaccine of pseudorabies virus Ea strain(TK-/gG-/LacZ+)was mixed with the two different purified recombinant proteins each, or both, with the doses of 2, 5 or 10 μg ml-1. Ten groups of pseudorabies negative antibody swines were immuned twice with tested vaccines with different doses, or control vaccine, respectively. The antibody liters of the test groups were detected by neutralization test, and the daily weight gains of swines were calculated and analyzed statistically. In the study, all the neutralizing antibody ti-ters in test groups were higher than the control group, and the recombinant proteins appeared a dose dependent adjuvant effect. The tested vaccines with 2 μg ml-1 pIL-2 and with 10 μg ml-1 pIL-2/pIL-6 got significant and extremely significant differences, compared with the vaccines without pILs. The difference of the daily weight gain indicated the potential positive influence of pIL-2 and pIL-6 on immune protection.

Vaccines’ Safety and Effectiveness in the Midst of Covid-19 Mutations

We examined the coronavirus classification and evolution through its multiple mutations that have increased its transmissibility rate up to 70% globally, threatening to undermine the promise of a number of emerging vaccines that primarily focus on the immune detection of the Spike trimer. The safety and effectiveness of different vaccination methods are evaluated and compared, including the mRNA version, the Adenovirus DNA, Spike protein subunits, the deactivated virus genres, and the live attenuated coronavirus. Mutations have been long considered as random events, or mistakes during the viral RNA replication. Usually, what can go wrong will go wrong;therefore, repeated transformations lead to the extinction of a virus. On the contrary, the aggregate result of over 300,000 Covid-19 variants has expanded its transmissibility and infectiousness. Covid-19 mutations do not degrade the virus;they empower and facilitate its disguise to evade detection. Unlike other coronaviruses, Covid-19 amino acid switches do not reflect the random unfolding of errors that eventually eradicate the virus. Covid-19 appears to use mutations adaptively in the service of its survival and expansion. We cite evidence that Covid-19 inhibits the interferon type I production, compromising adaptive immunity from recognizing the virus. The deleterious consequences of the cytokine storm where the CD8+ killer cells injure the vital organs of the host may well be a Covid-19 manoeuvring to escape exposure. It is probable that evolution has programmed Covid-19 with an adeptness designed to debilitate key systemic defences to secure its subsistence. To date the infectiousness of the Covid-19 pandemic is exponentially increasing, denoting the possibility of an even more dangerously elusive, inconspicuous, and sophisticated version of the disease.

In silico prediction of monovalent and chimeric tetravalent vaccines for prevention and treatment of dengue fever

Reverse vaccinology method was used to predict the monovalent peptide vaccine candidate to produce antibodies for therapeutic purpose and to predict tetravalent vaccine candidate to act as a common vaccine to cover all the dengue virus serotypes. Envelope（E）-proteins of DENV-1-4 serotypes were used for vaccine prediction using NCBI,Uniprot/Swissprot, Swiss-prot viewer, VaxiJen V2.0, TMHMM, BCPREDS, Propred-1, Propred and MHC Pred. Eproteins of DENV-1-4 serotypes were identified as antigen from which T cell epitopes, through B cell epitopes, were predicted to act as peptide vaccine candidates. Each selected T cell epitope of E-protein was confirmed to act as vaccine and to induce complementary antibody against particular serotype of dengue virus. Chimeric tetravalent vaccine was formed by the conjugation of four vaccines, each from four dengue serotypes to act as a common vaccine candidate for all the four dengue serotypes. It can be justifiably concluded that the monovalent 9-mer T cell epitope for each DENV serotype can be used to produce specific antibody against dengue virus and a chimeric common tetravalent vaccine candidate to yield a comparative vaccine to cover any of the four dengue virus serotype. This vaccine is expected to be highly immunogenic against dengue fever.

Studies on the correlation between human papilloma virus vaccine and premature ovarian failure

Cervical cancer is the most common malignant tumour of the female reproductive system,resulting in more than 500,000 new cases annually worldwide.In developing countries,cervical cancer ranks second in terms of cancer mortality among women.Human papilloma virus is the primary causative agent of cervical cancer,with approximately 70 percent of cervical cancers caused by high-risk types of human papilloma virus 16 and 18.There are currently three types of human papilloma virus vaccines available:bivalent,quadri-valent and nine-valent.However,in recent years,it is reported that cervical cancer vaccine can cause premature ovarian failure.Consequently,an extensive literature search to find out the correlation between human papilloma virus vaccine and premature ovarian failure became a priority.There is no sufficient evidence to support or prove that there is a link between the human papilloma virus vaccine and premature ovarian failure.Hence,the vaccine does not cause premature ovarian failure.

Evaluation of an attenuated vaccine candidate based on the genotype C of bovine parainfluenza virus type 3 in albino guinea pigs

Bovine parainfluenza virus type 3（BPIV3） is considered as one of the most important respiratory tract pathogens of both young and adult cattle, and widespread among cattle in the world. BPIV3 was first reported in China in 2008 and four strains of BPIV3 were isolated from Shandong Province, known as genotype C（BPIV3c）. Pathogen investigations had shown that BPIV3 c infection was very common among cattle in China. To date, BPIV3 can be classified into genotypes A, B and C based on genetic and phylogenetic analysis. Serological survey also demonstrates that BPIV3 infection is widespread in China, however, there is still no available vaccine for BPIV3 prevention in China nowadays. In the present study, the BPIV3 c strain SD0835 was continuously passaged on Madin-Darby bovine kidney（MDBK） cells for hundreds of times, and the pathogenicity of passage 209 was reduced in guinea pigs. The passage 209 of BPIV3 c strain SD0835 was used as a live vaccine candidate to immunize the guinea pigs. The vaccination results revealed that two vaccinations could induce excellent serum neutralizing antibody responses as well as proliferation of T lymphocytes. The vaccinated guinea pigs were well protected against challenge with a low passage of BPIV3 c strain SD0835. Additionally, the percentages of CD4~＋ and CD8~＋ T cell subsets of animals in vaccinated group increased after immunization; T cell subsets on day 2 after challenge in both groups decreased, and the decline of CD4~＋ and CD8~＋ T cell subsets levels of four guinea pigs in vaccinated group was relatively moderate, comparing with that of the control group. These data support further testing of the attenuated virus as an effective candidate vaccine.

Conservation of T cell epitopes between seasonal influenza viruses and the novel influenza A H7N9 virus

A novel avian influenza A(H7N9) virus recently emerged in the Yangtze River delta and caused diseases, often severe, in over 130 people. This H7N9 virus appeared to infect humans with greater ease than previous avian influenza virus subtypes such as H5N1 and H9N2. While there are other potential explanations for this large number of human infections with an avian influenza virus, we investigated whether a lack of conserved T-cell epitopes between endemic H1N1 and H3N2 influenza viruses and the novel H7N9 virus contributes to this observation. Here we demonstrate that a number of T cell epitopes are conserved between endemic H1N1 and H3N2 viruses and H7N9 virus. Most of these conserved epitopes are from viral internal proteins. The extent of conservation between endemic human seasonal influenza and avian influenza H7N9 was comparable to that with the highly pathogenic avian influenza H5N1. Thus, the ease of inter-species transmission of H7N9 viruses(compared with avian H5N1 viruses) cannot be attributed to the lack of conservation of such T cell epitopes. On the contrary, our findings predict significant T-cell based cross-reactions in the human population to the novel H7N9 virus. Our findings also have implications for H7N9 virus vaccine design.

Covid-19 Mutations and the Effect of Different Vaccines on Immune Memory

We traced the coronavirus classification and evolution,analyzed the Covid-19 composition and its distinguishing characteristics when compared to SARS-CoV and MERS-CoV.Despite their close kinship,SARS-CoV and Covid-19 display significant structural differences,including 380 amino acid substitutions,and variable homology between certain open reading frames that are bound to diversify the pathogenesis and virulence of the two viral compounds.A single amino acid substitution such as replacing Aspartate(D)with Glycine(G)composes the D614G mutation that is around 20%more infectious than its predecessor 614D.The B117 variant,that exhibits a 70%transmissibility rate,harbours 23 mutants,each reflecting one amino acid exchange.We examined several globally spreading mutations,501.V2,B1351,P1,and others,with respect to the specific amino acid conversions involved.Unlike previous versions of coronavirus,where random mutations eventually precipitate extinction,the multiplicity of over 300,000 mutations appears to have rendered Covid-19 more contagious,facilitating its ability to evade detection,thus challenging the effectiveness of a large variety of emerging vaccines.Vaccination enhances immune memory and intelligence to combat or obstruct viral entry by generating antibodies that will prohibit the cellular binding and fusion with the Spike protein,restricting the virus from releasing its contents into the cell.Developing antibodies during the innate response,appears to be the most compelling solution in light of the hypothesis that Covid-19 inhibits the production of Interferon type I,compromising adaptive efficiency to recognize the virus,possibly provoking a cytokine storm that injures vital organs.With respect to that perspective,the potential safety and effectiveness of different vaccines are evaluated and compared,including the Spike protein mRNA version,the Adenovirus DNA,Spike protein subunits,the deactivated virus genres,or,finally,the live attenuated coronavirus that appears to demonstrate the greatest effectiveness,yet,encompass a relatively higher risk.

Hepatitis C virus in the new era:Perspectives in epidemiology,prevention,diagnostics and predictors of response to therapy

Despite the great successes achieved in the fields of virology and diagnostics,several difficulties affect improvements in hepatitis C virus(HCV)infection control and eradication in the new era.New HCV infections still occur,especially in some of the poorest regions of the world,where HCV is endemic and long-term sequelae have a growing economic and health burden.An HCV vaccine is still no available,despite years of researches and discoveries about the natural history of infection and host-virus interactions:several HCV vaccine candidates have been developed in the last years,targeting different HCV antigens or using alternative delivery systems,but viral variability and adaption ability constitute major challenges for vaccine development.Many new antiviral drugs for HCV therapy are in preclinical or early clinical development,but different limitations affect treatment validity.Treatment predictors are important tools,as they provide some guidance for the management of therapy in patients with chronic HCV infection:in particular,the role of host genomics in HCV infection outcomes in the new era of direct-acting antivirals may evolve for new therapeutic targets,representing a chance for modulated and personalized treatment management,when also very potent therapies will be available.In the present review we discuss the most recent data about HCV epidemiology,the new perspectives for the prevention of HCV infection and the most recent evidence regarding HCV diagnosis,therapy and predictors of response to it.

An update on the 2014 Ebola outbreak in western Africa

The recent Ebola outbreak in Western Africa was the most devastating outbreak witnessed in recent times,There have been remarkable local and international efforts to control the crisis,Ebola Virus Disease is the focus of immense research activity,The progression of events in the region has been evolving swiftly and it is of paramount importance to the medical community to be acquainted with the situation,Over 28 000 people were inflicted with the condition,over 11 000 have died,Novel data has emerged regarding modes of transmission,providing rationale for recent flare-ups,Similarly,studies on survivors are elucidating the later stages of the disease recovery process,Novel techniques for diagnosis are also discussed,Finally,the current research regarding treatment and vaccine development is reviewed,particularly the implementation of r VSV-ZEBOV vaccination programs.

Hepatitis elimination by 2030: Progress and challenges

Globally, over 300 million people are living with viral he-patitis with approximately 1.3 million deaths per year. In 2016, World Health Assembly adopted the Global Health Sector Strategy on viral hepatitis to eliminate hepatitis by 2030. Different World Health Organization member countries are working on hepatitis control strategies to achieve hepatitis elimination. So far, only 12 countries are on track to achieve hepatitis elimination targets. The aim of the study was to give an update about the progress and challenges to achieving hepatitis elimination by 2030. According to the latest data, 87% of infants had received the three doses of hepatitis B virus （HBV） vaccination in the frst year of their life and 46% of infants had received a timely birth dose of HBV vaccination.There is a strong need to improve blood and injection safety. Rates of hepatitis B and C diagnosis are very low and only 11% of hepatitis B and C cases are diagnosed. There is a dire need to speed up hepatitis diagnosis and find the missing millions of people living with viral hepatitis. Up to 2016, only 3 million hepatitis C cases have been treated. Pricing of hepatitis C virus drugs is also reduced in many countries. The major hurdle to ach-ieve hepatitis elimination is lack of finances to support hepatitis programs. None of the major global donors are committed to invest in the fght against hepatitis. It will be very diffcult for the low and middle-income countries to fund their hepatitis control program. Hepatitis elimination needs strong fnancial and political commitment, support from civil societies, and support from pharmaceutical and medical companies around the globe.

Sex bias in response to hepatitis B vaccination in end-stage renal disease patients:Meta-analysis

AIM： To systematically review the literature for studies investigating the potential effect of gender of dialysis patients on the immunogenicity of hepatitis B virus vaccines. METHODS： Literature searches were conducted by the MEDLINE and Google Scholar. The key words used included “hepatitis B （HB）”, “vaccine”, “dialysis”, “hemodialysis”, “sex”, “male” and “female”. Data of seroresponse to HB vaccine in clinical trials regarding sex of the recipients have been achieved and analyzed. Finally data from 19 clinical trials have been pooled and analyzed.RESULTS： Analysis of response to HB vaccination in our dialysis population showed males significantly res-pond less to hepatitis B vaccination （P = 0.002, Z = 3.08） with no significant heterogeneity detected [P = 0.766; heterogeneity χ2 = 14.30 （df = 19）; I2 = 0%]. A reanalysis of the pooled data was conducted regarding the dialysis mode to evaluate potential differential impact of sex on HB vaccine response. Hemodialysis was the only subgroup that showed a signifcant difference regarding dialysis mode in response to HB vaccination regarding sex （ P = 0.042, Z = 2.03）.CONCLUSION： This Meta-analysis showed significant effect for the sex of chronic kidney disease and dialysis patients on the immunogenicity of HB vaccine. This sex discrimination was most prominent among hemodialysis patients.

Genomic similarity and antibody-dependent enhancement of immune serum potentially affect the protective efficacy of commercial MLV vaccines against NADC30-like PRRSV

Porcine reproductive and respiratory syndrome(PRRS)is one of the most significant diseases affecting the pig industry worldwide.The PRRSV mutation rate is the highest among the RNA viruses.To date,NADC30-like PRRSV and highly pathogenic PRRSV(HP-PRRSV)are the dominant epidemic strains in China;however,commercial vaccines do not always provide sufficient cross-protection,and the reasons for insufficient protection are unclear.This study isolated a wild-type NADC30-like PRRSV,SX-YL1806,from Shaanxi Province.Vaccination challenge experiments in piglets showed that commercial modified live virus(MLV)vaccines provided good protection against HP-PRRSV.However,it could not provide sufficient protection against the novel strain SXYL1806.To explore the reasons for this phenomenon,we compared the genomic homology between the MLV strain and HP-PRRSV or NADC30-like PRRSV and found that the MLV strain had a lower genome similarity with NADC30-like PRRSV.Serum neutralization assay showed that MLV-immune serum slightly promoted the homologous HP-PRRSV replication and significantly promoted the heterologous NADC30-like PRRSV strain replication in vitro,suggesting that antibody-dependent enhancement(ADE)might also play a role in decreasing MLV protective efficacy.These findings expand our understanding of the potential factors affecting the protective effect of PRRSV MLV vaccines against the NADC30-like strains.

Factors affecting effectiveness of vaccination against hepatitis B virus in hemodialysis patients

Hepatitis B virus(HBV)is a major global health problem.Despite the success of the general measures against blood transmitted infections in hemodialysis(HD)units,the prevalence of HBV infection among the HD patients is still high.Thus vaccination against HBV is indicating in this population.However,compared with the general population the seroprotection achieved in HD patients remains relatively low,at about 70%.In this review patient,HD procedure and vaccine-associated factors that affect the efficacy of HBV vaccination are analyzed.Also alternative routes of HBV vaccine administration as well as new and more immunogenic vaccine formulations are discussed.However,besides scientific progress,vigilance of HD physicians and staff regarding the general measures against the transmission of blood borne infections and the vaccination against HBV is also required for reducing the prevalence of this viral infection.

Seroepidemiology of hepatitis A virus in Kuwait

AIM: To fi nd the current seroepidemiology of hepatitis A virus (HAV) in Kuwait.METHODS: A total of 2851 Kuwaitis applying for new jobs were screened.RESULTS: HAV-positive cases were 28.8%; 59% were males and 41% were females. The highest prevalence was in the Ahmadi area. High prevalence was among the group of non-educated rather than educated parents. This is the fi rst study in Kuwait demonstrating the shifting epidemiology of HAV.CONCLUSION: This study reflects the need of the Kuwaiti population for an HAV vaccine.

Universal influenza virus vaccines： what can we learn from the human immune response following exposure to H7 subtype viruses？

Several universal influenza virus vaccine candidates based on eliciting antibodies against the hemagglutinin stalk domain are in development. Typically, these vaccines induce responses that target group 1 or group 2 hemagglutinins with Httle to no cross-group reactivity and protection. Similarly, the majority of human anti-stalk monoclonal antibodies that have been isolated are directed against group 1 or group 2 hemagglutinins with very few that bind to hemagglutinins of both groups. Here we review what is known about the human humoral immune response to vaccination and infection with H7 subtype influenza viruses on a polyclonal and monoclonal level. It seems that unlike vaccination with H5 hemagglutinin, which induces antibody responses mostly restricted to the group 1 stalk domain, H7 exposure induces both group 2 and cross-group antibody responses. A better understanding of this phenomenon and the underlying mechanisms might help to develop future universal influenza virus vaccine candidates.

Sexually transmitted infections of the anus and rectum

Sexually transmitted infections(STIs) represent a significant public health concern.Several STIs,once thought to be on the verge of extinction,have recently reemerged.This change is thought to be partially related to an increase in STIs of the anus and rectum.Importantly,the global human immunodeficiency virus and acquired immunodeficiency syndrome(HIV/AIDS) epidemic has contributed to the emergence of particular anorectal lesions that require specialized approaches.In this report,we review common anorectal STIs that are frequently referred to colorectal surgeons in the United States.Epidemiology,clinical presentation,and management are summarized,including the latest treatment recommendations.The particularity of anorectal diseases in HIV/AIDS is addressed,along with recent trends in anal cytology and human papillomavirus vaccination.