Testing human sera for antibodies against avian influenza viruses: Horse RBC hemagglutination inhibition vs. microneutralization assays

BACKGROUND: The hemagglutination inhibition (HI) assay is a frequently used method to screen human sera for antibodies against influenza A viruses. Because HI has relatively poor sensitivity in detecting antibodies against avian influenza A strains, a more complicated microneutralization (MN) assay is often preferred. Recent research suggests that the sensitivity of the HI assay can be improved by switching from the traditionally used turkey, guinea pig, human, or chicken RBCs to horse RBCs. OBJECTIVE: To evaluate the performance of the horse RBC HI when screening for human antibodies against avian influenza types H3, H4, H5, H6, H7, H9, H11, and H12. STUDY DESIGN: We evaluated the reproducibility of horse RBC HI and its agreement with MN results using sera from people exposed or not exposed to wild and domestic birds. RESULTS: The horse RBC HI assay had high reliability (90%-100%) and good agreement with MN assay results (52%-100%). CONCLUSION: The horse RBC HI assay is reliable, less expensive, less complex, and faster than the MN assay. While MN will likely remain the gold standard serologic assay for avian viruses, the horse RBC HI assay may be very useful as a screening assay in large-scale epidemiologic studies.     

Efficacy and safety of anti-CD45–saporin as conditioning agent for RAG deficiency

1. Download : Download high-res image (268KB)
2. Download : Download full-size image

     

广东省人群中人嗜T细胞病毒Ⅰ型感染的血清流行病学调查及其与人类疾病的关系

收集广东省各类人群血清标本２２２４份，用间接免疫荧光法检测人类嗜Ｔ细胞病毒Ⅰ型（ＨＴＬＶ－１）抗体，结果：ＨＴＬＶ－１抗体阳性３５份，总阳性率为１．５７％；其中健康人群血清１８１０份，抗体阳性２３份，阳性率为１２７％；献血员血清２４８份，抗体阳性１份，阳性率０４０％；白血病患者血清１０９份，阳性８份，阳性率７３４％，与健康人群比较，有非常显著性差异（Ｐ＜０００５）；神经系统疾病患者血清５７份，阳性３份，阳性率５２６％。     

Humoral immunity to immunodominant epitopes of Hepatitis C virus in individuals infected with genotypes 1a or 1b

Cellular immunity against multiple Hepatitis C virus (HCV) proteins is observed in patients acutely infected with HCV most of whom later resolve infection. We wished to assess humoral immunity in patients infected with HCV 1a or 1b genotypes in relation to viral load using plasma samples from HCV-infected individuals and a panel of peptides representing immunodominant epitopes of HCV structural and nonstructural proteins. Plasma from HCV 1a- and 1b-infected patients, respectively, were divided into two groups: patients with low viral load (<==100,000 RNA copies/ml) and patients with high viral load (>/=10,000,000 RNA copies/ml). The antigens were peptides representing epitopes from immunodominant regions of HCV core, E2, NS3, and NS4 proteins, as well as the hypervariable (HVR) epitopes in E2 from genotypes 1a and 1b. Individuals infected with HCV 1a evoked a stronger immune response to many immunodominant epitopes of HCV relative to individuals infected with HCV 1b. Moreover, among individuals infected with HCV 1a, those with low viral loads mounted significantly greater responses against these epitopes than did individuals with high viral loads. Our observations demonstrate that quantitatively different antibody responses are elicited against HCV depending on the genotype of infecting virus, and suggest that humoral immunity directed against multiple immunodominant epitopes in HCV 1a-infected individuals may help lower viral load in vivo.     

一起流行性脑脊髓膜炎疫情病例密切接触者及周围人群的脑膜炎奈瑟菌菌属类型及抗体检出情况调查

目的 对流行性脑脊髓膜炎患者的密切接触者及周围人群进行脑膜炎奈瑟菌菌属类型及抗体检测调查,为流脑防控工作提供科学依据。方法 采集病例密切接触者和周围人群的血清和咽拭子进行带菌及抗体检测。结果 共采集流脑患者密切接触者30人和周围人群147人,其中密切接触者共3人检出脑膜炎奈瑟菌阳性,且均为C群;周围人群共19人检出脑膜炎奈瑟菌阳性,其中B群17人,W135群2人。在抗体检测中,其中周围人群的检出率高于密切接触者（χ2 = 7.885,P＜0.05）;密切接触者中Y群检出率高于周围人群（χ2 = 12.638,P＜0.05）。在疫苗接种与抗体检出中,密切接触者的A群流脑多糖疫苗、A + C脑膜炎球菌结合疫苗的接种率与周围人群比较均无统计学上差异（P＞0.05）,同时A群与A + C群抗体检测在统计学上也无差异（P＞0.05）。但在未全程接种的A + C群抗体检测中,未全程接种的周围人群抗体阳性率高于密切接触者（χ2 = 6.021,P＜0.05）。结论 本起疫情检测菌属以B群为主,抗体检出以为A群为主,且疫苗接种率越高,抗体阳性检出率越高。     

潜、慢型克山病患者柯萨奇B组病毒特异性IgM、 IgG的检测

目的　了解柯萨奇B组病毒(CoxB)感染与克山病的相关关系。方法　采用间接酶联免疫吸附法对四川省克山病病区30例潜、慢型克山病患者血清中CoxB     

海南省2311例关节炎症状患者的莱姆病抗体血清学研究

目的探讨海南省关节炎症状患者的莱姆病感染状况,为莱姆病的防控提供依据。方法采用抽样调查方法,2013至2018年在海南省8个市(县)(海口市、三亚市、儋州市、东方市、文昌市、琼海市、琼中县、五指山市)的医疗机构,对其进行抽样调查,收集2 311例关节炎症状就诊的患者血清标本,并对临床资料进行描述性研究。采用间接免疫荧光法(IFA)对血清标本进行莱姆病抗体初筛检测,并采用免疫印迹法(WB)对IFA检测阳性的血清标本进行确诊实验。采用χ²检验进行统计分析。结果 IFA方法检测血清样本2 311份,166份阳性,阳性率7.18%。进一步用 WB方法确认,62份阳性, 莱姆病抗体阳性率为2.68%(62/2 311)。海南省不同地区关节炎症状患者的莱姆病抗体阳性率差异有统计学意义(χ²=40.636,P<0.001),琼中县阳性率最高,为8.81%(14/159);儋州市阳性率次之,为5.62%(5/89);东方市阳性率最低,为0.51%(2/394)。莱姆病血清抗体阳性率男性及女性分别是2.79%(33/1 182)和2.57%(29/1 129);各年龄组间的抗体阳性率在1.74%~3.64%,在性别和年龄间差异无统计学意义(χ²=0.110,P=0.740;χ²=1.938,P=0.747)。结论海南省8个市(县)均存在伯氏疏螺旋体感染导致的关节炎症状患者,但莱姆病抗体阳性率各市(县)存在差异,以琼中县最高。     

Comparison of influenza antibody titers among women who were vaccinated in the 2nd and the 3rd trimesters of pregnancy

BackgroundWe compared cord blood antibody titers in unvaccinated pregnant women to those vaccinated with seasonal influenza vaccine during the 2^nd and the 3^rd trimesters.MethodsPregnant women had cord blood collected at delivery for hemagglutination inhibition assay against vaccine reference viruses: A/California/07/2009 (H1N1)pdm09, A/Switzerland/9715293/2013 (H3N2), and B/Phuket/3073/2013 (Yamagata lineage). Geometric mean titer (GMT) ratios were calculated comparing vaccinated versus unvaccinated pregnant women, and women vaccinated in the 2^nd and the 3^rd trimesters. Proportions of women achieving defined titers were compared using the χ² test.ResultsOf 307 women, 190 (62%) were unvaccinated. Fifty and 67 were vaccinated during the 2^nd and the 3^rd trimesters, respectively. Median enrollment age was 29 years (interquartile range 24–34). Sixteen (5%) women had pre-existing conditions, but none were immunocompromised. GMT ratios comparing vaccinated and unvaccinated women were 5.90 (95% confidence interval [CI] 5.06–6.96) for influenza A/California, 5.39 (95% CI 4.18–6.08) for influenza A/Switzerland, and 5.05 (95% CI 4.43–5.85) for influenza B/Phuket. Similarly, the GMT ratios comparing the 3^rd and the 2^nd trimester vaccinated women were 2.90 (95% CI 2.54–3.39), 2.82 (95% CI 2.56–3.13), and 2.83 (95% CI 2.56–3.14), respectively. The proportions of women with defined titers for the three vaccine reference viruses did not differ between 2^nd and 3^rd trimester vaccinated women (titers ≥40: 68–92% versus 70–93%; ≥110: 32% versus 33–63%; and ≥330: 4–10% versus 3–21%).ConclusionsPregnant women vaccinated against influenza had more placental transfer of influenza antibodies to their infants than unvaccinated women. Placental transfer of antibodies was higher among those vaccinated in the 3^rd trimester than in the 2^nd trimester. There was no difference in the proportions of women achieving antibody titers corresponding to protection against influenza in children. Findings support the current World Health Organization’s recommendation that pregnant women may be vaccinated in either 2^nd or 3^rd trimester of pregnancy.     

Pertussis immunisation during pregnancy: Antibody levels and the impact of booster vaccine

Pertussis (whooping cough) is a highly infectious disease caused by Bordetella pertussis. Mothers lacking adequate immunity and contracting the disease represent the biggest risk of transmission to new-borns, for which the disease is often a threat. The aim of the study was to estimate the frequency of pertussis susceptibility among pregnant women, in order to point out the need for a vaccine recall during pregnancy, and to evaluate the antibody response in already vaccinated women. A cross-sectional observational study was conducted in the blood test centre of “St. Anna” Obstetrics and Gynaecology Hospital in Turin (Piedmont, Italy). Eligibility criteria included pregnant women coming to the centre for any blood test, aged 18 or above and with gestational age between 33 and 37 weeks at the moment of the blood draw. The data collection was carried out from May 2019 to January 2020 and the concentration of anti-Pertussis Toxin (anti-PT) IgG was measured through the Enzyme-Linked Immunosorbent Assay (ELISA) technique. Two-hundred women (median age 35) were enrolled: 132 (66%) had received at least one dose of pertussis vaccine, 82 of which during pregnancy. Recently vaccinated women had significantly higher antibody titres (even 12–15 times as high) compared to those vaccinated more than 5 years before or never vaccinated at all (p < 0.0001). Moreover, 95.1% of recently vaccinated women had anti-PT IgG levels above 10 IU/ml, and 85.4% above 20 IU/ml, while the same proportions were as low as 37% and 21% (respectively) in the group of women not vaccinated in pregnancy. This study confirmed that the vaccination is greatly effective in ensuring high antibody titres in the first months after the booster vaccine, with considerable differences in anti-PT IgG compared to women vaccinated earlier or never vaccinated at all, and therefore vaccinating pregnant women against pertussis still represents a valuable strategy.     

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.