Long-lasting heterologous antibody responses after sequential vaccination with A/Indonesia/5/2005 and A/Vietnam/1203/2004 pre-pandemic influenza A(H5N1) virus vaccines

BackgroundAvian influenza A(H5N1) viruses have caused sporadic infections in humans and thus they pose a significant global health threat. Among symptomatic patients the case fatality rate has been ca. 50%. H5N1 viruses exist in multiple clades and subclades and several candidate vaccines have been developed to prevent A(H5N1) infection as a principal measure for preventing the disease.MethodsSerum antibodies against various influenza A(H5N1) clade viruses were measured in adults by ELISA-based microneutralization and haemagglutination inhibition tests before and after vaccination with two different A(H5N1) vaccines in 2009 and 2011.ResultsTwo doses of AS03-adjuvanted A/Indonesia/5/2005 vaccine induced good homologous but poor heterologous neutralizing antibody responses against different clade viruses. However, non-adjuvanted A/Vietnam/1203/2004 booster vaccination in 2011 induced very strong and long-lasting homologous and heterologous antibody responses while homologous response remained weak in naïve subjects.ConclusionsSequential vaccination with two different A(H5N1) pre-pandemic vaccines induced long-lasting high level cross-clade immunity against influenza A(H5N1) strains, thus supporting a prime-boost vaccination strategy in pandemic preparedness plans.     

RSV neutralization assays – Use in immune response assessment

Respiratory syncytial virus (RSV) is a leading cause of respiratory illness among children and infants worldwide, yet no licensed vaccine exists to reduce the risk of disease. At least 16 RSV vaccine candidates are currently in clinical development and many are designed to induce robust virus neutralizing immune responses. RSV neutralizing antibody (nAb)-mediated interventions such as intravenous immunoglobulin (IVIG) and palivizumab provide passive protection against serious lower respiratory tract disease due to RSV, validating nAbs as a correlate of protection. To identify correlates of protection for vaccine candidates that have demonstrated their protective efficacy, an investigator can use assays designed to measure nAb responses. However, there is no standard method of measurement; individual laboratories have developed their own methods to measure the ability of nAbs to reduce the infectivity of a defined virus dose in a variety of cell lines, leading to establishment of the broad variety of RSV neutralization assay formats currently in use.Standardizing the RSV neutralization assay is an essential step toward better assessment of nAb responses to vaccine candidates. Use of a common reference standard by all makes comparing the immunogenicity of different vaccine candidates feasible. In the context of vaccine development, the WHO 1^st International Standard for Antiserum to RSV (RSV IS) has been shown to be suitable for harmonizing results across laboratories and assay formats used to measure nAb titers to RSV/A and RSV/B in human sera.This review describes the broad variety of RSV virus neutralization assay formats currently in use and the importance of the RSV IS for harmonization of results across formats and across laboratories. It also outlines good practices for key assay components and data analysis to promote the quality and consistency of measuring RSV nAb titers in serum specimens.     

Intranasal immunization with recombinant Vaccinia virus encoding trimeric SARS-CoV-2 spike receptor-binding domain induces neutralizing antibody

Respiratory transmission of SARS-CoV-2 is considered to be the major dissemination route for COVID-19, therefore, mucosal immune responses have great importance in preventing SARS-CoV-2 from infection. In this study, we constructed a recombinant Vaccinia virus (VV) harboring trimeric receptor-binding domain (RBD) of SARS-CoV-2 spike protein (VV_-tRBD), and evaluated the immune responses towards RBD following intranasal immunization against mice and rabbits. In BALB/c mice, intranasal immunization with VV_-tRBD elicited robust humoral and cellular immune responses, with high-level of both neutralizing IgG and IgA in sera against SARS-CoV-2 psudoviruses, and a number of RBD-specific IFN-γ-secreting lymphocytes. Sera from immunized rabbits also exhibited neutralization effects. Notably, RBD-specific secretory IgA (sIgA) in both nasal washes and bronchoalveolar lavage fluids (BALs) were detectable and showed substantial neutralization activities. Collectively, a recombinant VV expressing trimeric RBD confers robust systemic immune response and mucosal neutralizing antibodies, thus warranting further exploration as a mucosal vaccine.     

用单克隆抗体观察慢性肝炎患者细胞免疫状况的变化

本文用多种单克隆抗体对32例慢性肝炎患者的细胞免疫状况进行了研究。结果发现患者肝组织内淋巴细胞和单核、巨噬细胞浸润明显增加,坏死区浸润细胞主要是T_3~+和T_8~+细胞。B淋巴细胞浸润极少,浸润淋巴细胞表面IL—2受体阳性细胞与外周血淋巴细胞表面IL—2受体阳性细胞率均无改变。患者外周血单个核细胞改变为T_3~+下降,T_4/T_8比例下降,单核、巨噬细胞、B淋巴细胞及淋巴细胞表面HLA—DR、DP、DQ标志与正常人无差异。     

Reactivity of human sera in a sensitive, high-throughput pseudovirus-based papillomavirus neutralization assay for HPV16 and HPV18

Sensitive high-throughput neutralization assays, based upon pseudoviruses carrying a secreted alkaline phosphatase (SEAP) reporter gene, were developed and validated for human papillomavirus (HPV)16, HPV18, and bovine papillomavirus 1 (BPV1). SEAP pseudoviruses were produced by transient transfection of codon-modified papillomavirus structural genes into an SV40 T antigen expressing line derived from 293 cells, yielding sufficient pseudovirus from one flask for thousands of titrations. In a 96-well plate format, in this initial characterization, the assay was reproducible and appears to be as sensitive as, but more specific than, a standard papillomavirus-like particle (VLP)-based enzyme-linked immunosorbent assay (ELISA). The neutralization assay detected type-specific HPV16 or HPV18 neutralizing antibodies (titers of 160-10240) in sera of the majority of a group of women infected with the corresponding HPV type, but not in virgin women. Sera from HPV16 VLP vaccinees had high anti-HPV16 neutralizing titers (mean: 45000; range: 5120-163840), but no anti-HPV18 neutralizing activity. The SEAP pseudovirus-based neutralization assay should be a practical method for quantifying potentially protective antibody responses in HPV natural history and prophylactic vaccine studies.     

首次及重复感染HCV后抗体及HCV RNA的动态观察

本文报道对首次感染ＨＣＶ的１４人与重复输入含ＨＣＶ血的１１位感染者进行长达一年半的动态观察，总结出输入大量含ＨＣＶ血后导致的感染者在自然状态下ＨＣＶ ＲＮＡ及抗体变化的规律。７／８再次输入４００ｍｌ以上含ＨＣＶ血的感染者，其自身存在的高滴度抗体在受血后１～３个月下降０．５～１．０ＯＤ值。首次输出含ＨＣＶ血的感染者中，１１／１４的感染者３个月内ＡＬＴ高于参考值的３倍以上，而再次输入含ＨＣＶ血的患者中     

Binding and specificity of major immunoglobulin classes of preformed human anti-pig heart antibodies

Preformed human anti-pig antibodies isolated from perfused pig hearts were used to analyze the binding of various immunoglobulin classes to cultured pig kidney cells. All anti-pig immunoglobulins (i.e., IgG, IgA, and IgM) were localized on the cell surface by the use of an indirect immunofluorescence technique. Anti-pig immunoglobulins also competed for the pig cell surface epitopes with Griffonia simplicifolia lectin (GS-I-B₄), which is specific for -galactosyl residues. This study provides further evidence that preformed human antibodies recognizing -glactosyl-containing epitopes (anti-gal antibodies) could be an important factor in hyperacute rejection of pig organs.     

Transmission of antibodies to Chlamydia Psittaci and Coxiella Burnetii through eggs and “crop milk” in pigeons

Young semi-domesticated pigeons captured or hatched from eggs gathered in Bratislava during 1989–1991 were examined for complement fixing antibodies to Chlamydia psittaci and agglutinating antibodies to Coxiella burnetii. Antibodies to Ch. psittaci were present in 76% of birds younger than 24 h, in 47.7% between 1 and 10 days of age and in 12% of nestlings over 10 days old. Antibodies to Ch. psittaci were also detected in crop milk of 4.1% of 1 to 10 day old birds and in 4.5% of specimens older than 10 days. Antibodies to C. burnetii were not found in juvenile birds under 24 h old, but antibodies against this agent were present in 16.4% birds between 1 and 10 days old and in 18% over 10 days old. Antibodies to C. burnetii were also detected in crop milk collected from crops of 2% of the young birds between 1 and 10 days.     

Prevalence of yersinia antibodies in blood donors

Agglutinins titers against Y. enterocolitica 0:3, 0:5, 0:9 and Y. pseudotuberculosis I were determined by the microagglutination method in 777 blood donor sera.Titers of <- 1/10 were observed in 93.5% of the subjects for Y. enterocolitica 0:3, in 87.8% for Y. enterocolitica 0:9 and in 95.1% for Y. enterocolitica 0:5 and for Y. pseudotuberculosis I. Low level titers (1/10 – 1/20) were found in 11.4% to 23.1%. Titers of 1/40 were observed in 1.7% for Y. enterocolitica 0:3, in 1.4% for Y. enterocolitica 0:5, in 5.1% for Y. enterocolitica 0:9 and in 1.2% for Y. pseudotuberculosis I. Titers of 1/80 were seen in 0.2% for Y. enterocolitica 0:3, in 0.1% for Y. enterocolitica 0:5 and in 1.3% for Y. enterocolitica 0:9. Only in one donor's serum was a titer of 1/160 against Y. enterocolitica 0:9 found.The upper limit of normal titer at 15% cutoff level against Yersinia antigens, found in blood donor sera by the microagglutination test, was 1/10.     

胃癌相关抗原MG7-Ag模拟肽表位的筛选及测序分析

目的　从噬菌体呈现的随机肽库中筛选胃癌单克隆抗体MG7所识别的胃癌相关抗原的短肽模拟表位 ,为进一步研究胃癌相关抗原与单抗结合的结构基序奠定基础。方法　用胃癌单克隆抗体MG7对呈现于噬菌体衣壳蛋白pⅧ上的 2个九肽库分别进行亲和富集和免疫筛选 ;阳性克隆进一步用荧光标记和硝酸纤维素膜斑点印迹法证实其结合活性 ;经随机抽取部分阳性克隆进行DNA序列分析 ,推导出相应噬菌体呈现肽的氨基酸序列 ,通过序列比较分析相对保守的表位信息 ;运用HLA分子结合分析软件预测已测序短肽与HLA分子结合的可能性。结果　经反复多轮筛选和结合活性检测 ,从pⅧ和pⅧ cys 2个噬菌体肽库中分别得到了 12和 30个阳性克隆 ;通过对部分阳性克隆进行测序分析 ,推导相应的随机肽序列和序列比较分析 ,得到具有相对保守性的表位信息如PLX0 2 S、SAVR、XRMX、YARN等。经计算机预测分析 ,发现它们可与HLA多个分子结合。结论　PLX0 2 S、SAVR、XRMX、YARN等有可能为胃癌单克隆抗体MG7所识别的表位基序。