Influenza viruses are common pathogens causing respiratory infections in humans. Among the four seasonal influenza viruses, influenza A virus H3N2 has become the leading cause of seasonal influenza illness and death, posing a great threat to public health and the economy. Since it first emerged and caused a pandemic in 1968, H3N2 has been circulating repeatedly in human beings and continually evades host immune attack by antigenic drift, resulting in a decrease in vaccine efficacy. In this paper, the antigenic evolution of influenza A virus H3N2, the impact of antigenic evolution on the selection of vaccine strains and some models for predicting the evolution of influenza viruses were analyzed and reviewed, which paved the road for understanding the antigenic evolution of influenza virus and vaccine development.

Influenza has caused high morbidity and mortality worldwide, seriously endangering human health and life. The continuous mutation of influenza virus has brought new challenges to the prevention and treatment of influenza. Animal models provide convenience for a comprehensive understanding of influenza virus pathogenesis, transmission mechanism, vaccine development, and evaluation of therapeutic effects. The construction and use of animal models of influenza virus infection vary in different studies, and the application of different animal models also has its own characteristics. This article reviewed the current status of the construction and use of various animal models, and summarized the advantages and limitations of animal models in evaluating the efficacy of antibodies, drugs and vaccines, with the aim of providing reference for the selection and optimization of animal models in the future.

Influenza viruses are responsible for a large number of infections and deaths annually, posing a serious threat to public health. Vaccination is the most effective measure to prevent influenza virus infection. However, current seasonal influenza vaccines only protect against closely matched circulating strains. Even with extensive surveillance and annual reformulation, yearly updated vaccines are still a step behind the fast-evolving viruses, often resulting in poor matches or less effective vaccines. Due to the relatively complex evolution of influenza A viruses, it is a new idea and a new means to prevent influenza epidemics by using a series of innovative technologies to develop universal influenza vaccines that can provide extensive and long-lasting protection against influenza viruses. This review summarized the latest progress in the development of universal vaccines targeting HA in the past three years, including design methods for universal vaccines targeting HA, HA stem and other conserved epitopes, compared the advantages and disadvantages of different technologies, explored the impact of immunization programs and strategies, and discussed the potential challenges to be overcome, hoping to provide reference for the successful development of universal vaccines.

The importance of structural variants(SVs)for human phenotypes and diseases is now recognized.Although a variety of SV detection platforms and strategies that vary in sensitivity and specificity have been developed,few benchmarking procedures are available to confidently assess their performances in biological and clinical research.To facilitate the validation and application of these SV detection approaches,we established an Asian reference material by characterizing the genome of an Epstein-Barr virus(EBV)-immortalized B lymphocyte line along with identified benchmark regions and high-confidence SV calls.We established a high-confidence SV callset with 8938 SVs by integrating four alignment-based SV callers,including 109x Pacific Biosciences(PacBio)continuous long reads(CLRs),22 x PacBio circular consensus sequencing(CCS)reads,104x Oxford Nanopore Technologies(ONT)long reads,and 114×Bionano optical mapping plat-form,and one de novo assembly-based SV caller using CCS reads.A total of 544 randomly selected SVs were validated by PCR amplification and Sanger sequencing,demonstrating the robustness of our SV calls.Combining trio-binning-based haplotype assemblies,we established an SV benchmark for identifying false negatives and false positives by constructing the continuous high-confidence regions(CHCRs),which covered 1.46 gigabase pairs(Gb)and 6882 SVs supported by at least one diploid haplotype assembly.Establishing high-confidence SV calls for a benchmark sample that has been characterized by multiple technologies provides a valuable resource for investigating SVs in human biology,disease,and clinical research.

Influenza virus has a continuous and extensive impact on human health around the world. Its extensive animal host characteristics and highly variable characteristics lead to continuous antigen drift and change of susceptible populations, causing repeated global influenza epidemics, and also affecting the protective effect of seasonal influenza vaccine. This research in a number of subtypes of influenza a virus, for example, from the antigenic drift of antigenicity, influence of the seasonal influenza vaccine strains and popular strain compatibility, broad-spectrum flu vaccine development train of thought, etc. summarizes the progress of relevant research, to deepen the understanding of the influenza virus antigenic evolution, provide reference for flu vaccine development in the future.

Influenza virus has a continuous and extensive impact on human health around the world. Its extensive animal host characteristics and highly variable characteristics lead to continuous antigen drift and change of susceptible populations, causing repeated global influenza epidemics, and also affecting the protective effect of seasonal influenza vaccine. This research in a number of subtypes of influenza a virus, for example, from the antigenic drift of antigenicity, influence of the seasonal influenza vaccine strains and popular strain compatibility, broad-spectrum flu vaccine development train of thought, etc. summarizes the progress of relevant research, to deepen the understanding of the influenza virus antigenic evolution, provide reference for flu vaccine development in the future.

The ongoing pandemic of Coronavirus disease 19 (COVID-19) is caused by a newly discovered β Coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). How long the adaptive immunity triggered by SARS-CoV-2 can last is of critical clinical relevance in assessing the probability of second infection and efficacy of vaccination. Here we examined, using ELISA, the IgG antibodies in serum specimens collected from 17 COVID-19 patients at 6-7 months after diagnosis and the results were compared to those from cases investigated 2 weeks to 2 months post-infection. All samples were positive for IgGs against the S- and N-proteins of SARS-CoV-2. Notably, 14 samples available at 6-7 months post-infection all showed significant neutralizing activities in a pseudovirus assay, with no difference in blocking the cell-entry of the 614D and 614G variants of SARS-CoV-2. Furthermore, in 10 blood samples from cases at 6-7 months post-infection used for memory T-cell tests, we found that interferon γ-producing CD4
Adaptive Immunity/physiology* ; Adult ; Aged ; Antibodies, Neutralizing/blood* ; COVID-19/immunology* ; Cohort Studies ; Female ; Humans ; Immunoglobulin G/blood* ; Male ; Middle Aged ; SARS-CoV-2/immunology* ; T-Lymphocytes/physiology* ; Time Factors ; Viral Proteins/immunology*

Antibody dependent enhancement (ADE) is a common phenomenon in virology. It is involved in the mechanisms of infections caused by Dengue virus (DV), severe acute respiratory syndrome coronavirus (SARS-CoV), influenza virus, HIV and other viruses and affects the research and development of vaccines against them. Because the pre-existing specific antibodies or antibodies at sub-neutralizing titer can enhance the infectivity of viruses, leading to disease aggravation, vaccination may promote infection instead of preventing it. This article focused on the impact of ADE on the research and development of vaccines and the assessment of ADE.

Objective:To analyze the neutralization properties of different genotypes and mutants of severe fever with thrombocytopenia syndrome virus (SFTSV).Methods:Pseudoviruses of SFTSV of different genotypes and mutants were constructed using VSVΔG-Fluc*G backbone. Neutralization assays were established based on the pseudoviruses. DNA vaccines for different SFTSV genotypes were prepared. Serum samples were collected from guinea pigs immunized with the DNA vaccines. Neutralizing antibodies in serum samples from immunized guinea pigs and naturally infected patients were detected using neutralization assays and analyzed.Results:The pseudoviruses of five genotypes and 43 mutants were successfully constructed and the neutralization assays based the pseudoviruses were successfully established after optimizing the reaction parameters. The dilution multiple corresponding to the inhibition rate of neutralizing antibody to half of the pseudovirus infection was taken as the titer of neutralizing antibody by the reduction in pseudovirus reporter gene. The neutralization antibody titers in naturally infected patients and immunized guinea pigs were respectively in the ranges of 1∶100-1∶43 000 and 1∶100-1∶2 500 when detected with the reference HB29 pseudovirus. The neutralization antibody titers ranged from 1∶100-1∶2 500 after immunization with different genotypes of DNA vaccines. No significant statistical difference in neutralization antibody titer was observed among different genotypes or mutant strains.Conclusions:The neutralization properties of different genotypes and mutants showed no significant change, which would be very useful for developing vaccines.

Objective: To discuss the characteristics of symptoms improvement based on the follow-up evaluation of Eustachian tube balloon dilation medium to long-term efficacy in patients with symptomatic Eustachian tube dysfunction (SETD). Methods: Patients from 2015 to 2017 were followed up after Eustachian tube balloon dilation (with the sense of aural fullness, or tinnitus and hearing ambiguity). All participants had been done ETDQ-7 before surgery and were re-evaluated with ETDQ-7 in follow-up. The improvement of overall and individual symptoms scores in ETDQ-7, the effects of gender and the difference of scores at different stages (12-18 months, 18-24 months and 24-30 months) after the operation were analyzed. Results: There were 29 patients, including 16 males and 13 females, whose age ranged from 20 to 62 years old. The medium to long-term score of ETDQ-7 significantly declined after surgery (27.0±7.9 vs. 14.1±7.5, P<0.05). Among all symptoms, symptoms like "blockage feeling in ear or being like under the water, constriction feeling" , "sound of blisters or explosions in the ear" decreased obviously (P<0.05). Comparing different stages after surgery, the scores of ETDQ-7 existed no difference (P>0.05). And the difference of gender showed no significant influence on surgery effects. Conclusion The subjective symptoms of patients with Eustachian tube dysfunction diagnosed with SETD can be significantly improved in the medium to long-term follow-up after Eustachian tube balloon dilation, and the degree of improvement is not linearly related to the postoperative time.