Evaluation of an anti-HIV-1/2 antibodies detection kit based on counting immunoassay in whole blood

We evaluated a novel anti-human immunodeficiency virus type-1/2 (HIV-1/2) antibody detection kit for detecting anti-HIV-1/2 antibodies in whole blood based on the counting immunoassay (CIA) using an automated immunochemical analyzer (PAMIA-40i). This kit to detected all antibodies tested including those against HIV-1 subtype A to F, B/D in group M, HIV-1 group O, and HIV-2, and captured antibodies 4 to 7 days earlier than immunochoromatocraphic tests in the commercial seroconversion panel. In this study using 70 HIV-seropositive patients and 90 HIV-seronegative healthy individuals, both sensitivity and specificity were 100%. This automatic system using CIA for whole blood can be completed within 15 min and examine many samples simultaneously. This system used latex-counting technology and reliably detects the low-titer antibodies in whole blood.     

Evaluation of an HIV screening assay kit for the combined detection of anti-HIV-1/2 antibodies and HIV p24 antigen]

We have evaluated a new HIV screening assay kit (Genscreen HIV Ag-Ab) for the HIV antigen-antibody combined test by comparing with two HIV antigen-antibody combined assay kits (VIDAS HIV DUO, Enzygnost HIV integral). Genscreen HIV Ag-Ab is a microwell plate enzyme immunoassay for the detection of HIV infection, based on the detection of anti-HIV-1/2 antibodies and HIV p24 antigen in human serum or plasma. In this study, 90 samples of HIV-1 antibody positive sera and 670 samples of HIV negative sera were examined. The sensitivity was 100% and the specificity was 99.7%. All of HIV-1 group M sera (subtypes A to G and B/D), HIV-1 group O sera and HIV-2 sera in worldwide HIV performance panel-302 were positive with Genscreen HIV Ag-Ab. Ten commercially available HIV-1 seroconversion panels were tested to evaluate sensitivity of three HIV antigen-antibody combined assay kits. Genscreen HIV Ag-Ab detected infection at the same bleeds as VIDAS HIV DUO in 8 of 10 seroconversion panels and 1 to 2 bleeds earlier than Enzygnost HIV integral in 5 of 10 seroconversion panels. However, VIDAS HIV DUO indicated false negative on 5th bleed in panel BB (PRA952). The result of the specimen was positive on 3rd bleed, equivocal on 4th bleed, negative on 5th bleed and again positive on 6th bleed. All of these specimens were positive by Genscreen HIV Ag-Ab. Therefore, Genscreen HIV Ag-Ab that shorten the window period is a useful and reliable for HIV screening test, especially in case of primary infection.     

Evaluation of an enzyme immunoassay for the combined detection of antibodies to HIV-1, HIV-2, HTLV-I and HTLV-II.

OBJECTIVE: To assess the sensitivity and specificity of a newly-developed assay (Bioelisa HIV-1 + 2, HTLV-1 + 2) for the simultaneous detection of HIV-1, HIV-2, HTLV-I and HTLV-II antibodies in human serum or plasma specimens. METHODS: A panel of 775 well characterized serum or plasma samples was studied. This included samples confirmed to contain antibodies to HIV-1 (n = 46), HIV-2 (n = 19), HTLV-I (n = 49) and HTLV-II (n = 12), samples containing low titres of anti-HIV antibody (n = 14) and samples collected during HIV seroconversion (n = 36). Eighty-three sera samples which were reactive in one or more HIV or HTLV screening assays, but which could not be confirmed to contain anti-HIV-1/2 or anti-HTLV-I/II antibodies, were also examined. RESULTS: Excluding the seroconversion samples and those selected on the basis of false reactivity in other screening assays, the Bioelisa kit had a sensitivity of 100% for antibody to all four viruses and a specificity of 98.8%. The ability of the kit to detect anti-HIV during seroconversion was similar to that of several other synthetic HIV-antigen-based screening kits currently in use. CONCLUSIONS: Our findings indicate that the Bioelisa kit is sufficiently accurate to screen for both HIV and HTLV infections and that it warrants larger scale trials. Its use might allow blood donor screening for HTLV infection to be introduced more widely at modest extra cost [corrected].     

Recombinant envelope protein of HIV-1 subtype E as antigen in HIV-1 antibody detection enzyme immunoassay

In order to develop a reliable and inexpensive serodiagnostic method to be used for anti-HIV antibody detection in Thailand, recombinant envelope (TM or gp41 subunit) protein of HIV-1 subtype E was produced from prokaryotic cell (Escherichia coli) as the source of antigen in enzyme immunoassay (TE diagnostic EIA kit). HIV-1 gp41 subunit of subtype E was successfully expressed in E. coli in the form of polyhistidine-tagged proteins, comprising of rgp41A (601 bases N-terminal half of TM or 25kDa) and rgp41B (560 bases C-terminal half of TM or 24 kDa) by using an expression vector, pBAD/His C. The amount of protein, dilution of sera, and anti-human IgG labeled HRP used in the EIA test optimized by a checker board titration of the protein and seropositive or seronegative sera, were 5.0 microg/ml, 1:300, and 1:4,000, respectively. The blinded test evaluation of TE-diagnostic EIA in 500 seropositive and 500 seronegative sera which have been simultaneously tested by two available commercial kits and compared with our TE diagnostic EIA, gave 99.6% sensitivity and specificity. The other known genetic subtypes sera such as subtype A (n=5), B (n=9), C (n=4) and D (n=5) were also positive with this EIA. The estimated manufacturer cost per test of rgp41 based anti-HIV antibody detection EIA or TE-diagnostic EIA was about 15 baht. This recombinant envelope (gp41 or TM) protein from HIV-1, which can be produced in large quantities without any hazards from growing the virus and has lower cost to produce anti-HIV antibody serological diagnostic kit, should be considered as an HIV screening test in Thailand.     

吸毒人群尿液、血液平行检测艾滋病病毒1型抗体结果分析

目的 利用吸毒人群尿液和血液标本比较不同方法检测艾滋病病毒1型(HIV-1)抗体结果的一致性。方法 平行采集强制戒毒所234名吸毒者的尿液和血液标本,应用酶联免疫吸附试验(ELISA)分别测定不同标本中HIV-1抗体。结果234人中5人血液标本HIV-1抗体为阳性,其平行尿液标本中4人阳性,另1人蛋白印迹试验确认为阴性。结果显示:两种标本检测HIV-1抗体的符合率为99.6％。结论 尿液标本ELISA试剂的检测结果是可靠的。     

Relevance of antibody content and test format in HIV testing of pooled sera.

OBJECTIVE: To determine the effects of HIV-1 antibody level and test-format characteristics on testing pooled sera. DESIGN: This study was designed with a laboratory exercise followed by test observations on serosurveillance samples. METHODS: Sera with low, medium and high (n = 22, 12 and 20, respectively) antibody titers were pooled with HIV-1-negative sera and tested with two enzyme-linked immunosorbent assays (ELISA) and a particle agglutination test. The same kits were used to test single and pooled (batches of five, 10 and 20) samples collected from 3000 blood donors and sex workers. These samples were then seeded with 50 varying antibody-containing sera and similarly tested. Initial reactivities, sensitivities, and specificities for all test kits were calculated and compared. RESULTS: In the laboratory exercise, all reactive pools of five were detected. False-negative pools in batches of 10 and 20 with low antibody titers were noted with one or both ELISA, but not with the particle agglutination method. Testing 3000 samples revealed three confirmed reactive samples and 100% sensitivity/specificity for all kits, for both single and pooled sera testing. Increased initial reactivity (IR) was noted for the two ELISA. Examinations of pools of the seeded 3000 samples with the two ELISA showed false-negative reactivity with pools of 10 and 20 when pools contained low antibody sera (sensitivities and specificities of 92-97.9% and 98.1-100%, respectively). Again, increased IR was seen with the ELISA. False-negative pool and increased IR was not seen with the agglutination test (sensitivity/specificity 100%). CONCLUSIONS: We recommend the use of the particle agglutination assay for testing pooled sera of batches of 20 or less. Components of reactive pools should then be tested and reactive samples should undergo supplementary testing. Pooled samples tested by ELISA should not exceed five per batch. Retesting of reactive pools, testing of its components, and supplemental test(s) of reactive sera should then follow. The optimum pool size for most laboratories is five, with the best technical and economic performance seen with the particle agglutination assay.     

ELISA法检测尿液中HIV-1抗体的研究分析

目的 探讨艾滋病病毒(HIV)感染者晨尿、非晨尿和血液中HIV-1抗体检测结果的一致性，引进尿液HIV-1抗体检测方法。方法 平行采集吸毒人员血液和尿液标本，分别用血液和尿液酶联免疫吸附试验(ELISA)法检测HIV抗体，阳性血清标本送云南省疾病预防控制中心确认。结果 检测483人，血检阳性91人，晨尿检测阳性96人，两种方法一致性98．96％。对应晨尿阳性者采集非晨尿和阴性对照尿液标本各91份(其中血液标本检测HIV抗体阳性者86份)，检出阳性86份，阴性5份，非晨尿标本与血液标本检测结果一致。以血液标本检测结果为准，晨尿标本检测HIV-1抗体的灵敏度100％，特异度98．72％；非晨尿标本检测HIV-1抗体的灵敏度和特异度均为100％。结论 尿液ELISA法检测HIV-1抗体结果可靠，非晨尿可代替晨尿作HIV-1抗体筛查。     

Sendai virus-based production of HIV type 1 subtype B and subtype E envelope glycoprotein 120 antigens and their use for highly sensitive detection of subtype-specific serum antibodies.

We previously described a Sendai virus (SeV)-based expression system for the recombinant gp120 of HIV-1 subtype B (rgp120-B), which has permitted the production of antigenetically and functionally authentic gp120 at a concentration as high as 6 microg/ml of culture supernatant (Yu D et al.: Genes Cells 1997;2:457-466). Here the same procedure was successfully applied to the production of HIV-1 subtype E gp120 (rgp120-E). The remarkable production of the proteins by the SeV expression system enabled us to use crude culture supernatants for serological and functional studies of gp120s. The immunological authenticity of rgp120-E was verified by patient sera and anti-V3 loop monoclonal antibodies specific for HIV-1 subtypes B and E. CD4-binding properties were corroborated by FACS analyses. The rgp120s were then used in an enzyme immunoassay (rgp120-EIA) to detect antibodies in the sera of HIV-1-infected individuals, and the performance was assessed in comparison with a conventional V3 loop peptide EIA (V3-EIA). The initial evaluation of a serum panel (n = 164) consisting of 76 subtype E and 88 subtype B sera revealed that the rgp120-EIA was nearly 1000-fold more sensitive than the V3-EIA and was able to detect subtype-specific antibody with 100% sensitivity and with a complete correlation with the genotypes, whereas the V3-EIA failed to detect 9 and 24% of the same subtype E and B sera, respectively. Furthermore, a study employing a panel of 28 international sera with known genotypes (HIV-1 subtypes A through F) confirmed the remarkable specificity of this method. An EIA reactivity higher than 1.0 was an unambiguous predictor of HIV-1 subtype E and B infections. The data imply the presence of strong subtype-specific epitopes for antibody bindings to these rgp120s.     

Evaluation of a Combined HIV-1/2 and HTLV-I/II Assay for Screening Blood Donors

A combined immunoassay for the simultaneous detection of antibodies to HIV-1/2 and HTLV-I/II (Bioelisa, Launch Diagnostics) has been evaluated to determine its suitability for routine use in blood donor screening. 84,222 donations were tested from 76,452 donors. One HIV- and 1 HTLV-I-positive donor were identified. The specificity was 99.7%, and the sensitivity for anti-HIV-1, anti-HIV-2, and anti-HTLV-I on 173 positive sera was 100%; 2 of 25 anti-HTLV-II-positive sera were non-reactive. Although the specificity of the assay is not as high as that of HIV-1/2 kits currently in UK transfusion use, the information gained about donor HTLV antibody status makes the test an attractive alternative to them.     

吸毒人群尿液血液标本HIV-1抗体ELISA检测对比分析

目的　用酶联免疫吸附试验 (ELISA)检测吸毒人群尿液标本中艾滋病病毒 1型 (HIV 1 )抗体 ,与血清学检测结果进行比较。方法　采集某市劳教所吸毒者尿液、血液标本 354例 ,HIV 1抗体阳性吸毒者复检尿液标本1 9例 ,共计 373例。应用ELISA初筛试剂检测尿液及血液标本中HIV 1抗体 ,阳性者取其血液标本进一步用Genelabs试剂做蛋白印迹 (WB)试验确认。结果　尿液、血液标本中检测HIV 1抗体的特异性为 99 72 % ,尿试剂的假阳性率为 0 2 8% ;血液标本HIV 1抗体阳性者 ,尿液标本检测也呈阳性 ,灵敏度为 1 0 0 %。结论　尿液标本用ELISA方法检测HIV 1抗体与血液标本ELISA方法的检出率有高度的一致性。尿试剂适用于对高危人群进行尿液HIV 1抗体的筛查工作     

戊型肝炎病毒抗体双抗原夹心法ELISA的建立与初步应用

目的　建立抗戊型肝炎病毒 (HEV)抗体检测的双抗原夹心ELISA(DS -ELISA) ,并应用于多种动物血清的检测。方法　将大肠杆菌表达的一段HEVORF2区重组抗原分别包被微孔板和进行辣根过氧化物酶 (HRP)标记 ,利用 5份阳性血清和 4 0份阴性血清建立双抗原夹心ELISA ;用 4 0 0份义务献血员血清比较双抗原夹心ELISA与间接法IgG抗体ELISA的符合情况 ;用 3只HEV感染猴系列血清比较双抗原夹心ELISA试剂和Genelabs公司HEVIgG试剂 ;用双抗原夹心ELISA试剂检测新疆地区的部分牛、绵羊、山羊、猪血清和上海地区的部分鸡血清中的HEV抗体。结果　建立了检测HEV抗体的双抗原夹心ELISA方法 ,对 4 0 0份义务献血员血清的检测表明其与间接法IgG抗体ELISA试剂的符合情况良好 ,并且有更高的s/co比值 ;与Genelabs公司HEVIgG试剂的比较表明双抗原夹心ELISA试剂的检出更早 ,尤其是持续时间及强度明显优于Genelabs试剂 ;在所检测的各种动物中均发现了HEV抗体 ,其中猪抗体的阳性率最高 ,表明双抗原夹心ELISA试剂可同时用于不同动物的抗HEV抗体检测。结论　利用大肠杆菌表达的HEV重组抗原建立了双抗原夹心法ELISA ,并可同时用于不同动物的抗HEV抗体检测。     

How many bloods will a 'HIVCHEK' check? Multiple tests for HIV antibody for a single screening kit.

Detection of HIV infection in blood donors or populations is usually by testing sera for antibodies to HIV-1 and HIV-2. Screening tests are now highly sensitive and specific, but still expensive and scarce in Africa. We tested the commercially available kits 'HIVCHEK 1 + 2' in two field laboratories, on specimens from blood donors and antenatal women in rural Zaire. We describe a method of using one test kit for up to five serum samples, saving money and time. In 491 antenatal mothers in Eastern Zaire, among whom the HIV seroprevalence was 3.3%, we compared 'HIVCHEK' results with results obtained by ELISA and Western blot. The 'HIVCHEK' multiple-sample method had a sensitivity of 82% and a specificity of 99.6%. In an area with an HIV seroprevalence of < 4%, using 'HIVCHEK' by the multiple sample method would lead to a saving of about 2,400 pounds for every 1000 individuals tested.     

HIV抗体快速诊断试剂的评估

目的 通过对艾滋病病毒(HIV)抗体快速诊断试剂的质量评估，筛选检测性能好的试剂，为艾滋病自愿咨询检测(VCT)提供依据。方法 用国家艾滋病参比实验室提供的50份参比样品、来自不同人群的400份样品、两套BBI(BOSTON BIOMEDICA，INC)抗体阳转血清盘(包括10份样品)，对8个厂家的HIv抗体快速诊断试剂的敏感性、特异性进行了评估。结果 被评价的各种快速诊断试剂的敏感性为97．71％～100％，特异性为81．78％～99．63％；阳性预示值为72．78％～99．22％，阴性预示值为98.89％～100％；用BBI血清盘检测时的试剂敏感性及特异性均为100％。结论 HIV抗体快速诊断试剂有较好的检测性能，有些试剂的敏感性及特异性均在95％以上，适合在发展中国家的VCT场所、仪器设备缺乏的实验室、偏远地区的血液筛查及职业暴露后的快速诊断中使用。     

Comparison of different kits in the detection of autoantibodies to cardiolipin and beta2glycoprotein 1

OBJECTIVE: To estimate the performance characteristics of 10 commercial kits and one in-house kit for the detection and quantification of anticardiolipin (aCL) (six kits) and anti-beta2glycoprotein 1 (anti-beta2GP1) (five kits) antibodies, and to evaluate the degree of variability between these different kits. METHODS: We determined the presence of aCL and anti-beta2GP1 IgG and IgM antibodies in 67 sera from 62 patients and reviewed the data separately. Each serum sample was tested with six commercial aCL determination kits and with four commercial and one in-house anti-beta2GP1 determination kit. We then analysed the operating characteristics of each kit (sensitivity, specificity, positive and negative predictive values) and we analysed the absolute and 2 x 2 agreements. RESULTS: The 62 patients included had primary antiphospholipid syndrome (APS) in 10 cases, secondary APS for eight, systemic lupus (SLE) for 23 and other diagnoses for the remaining 21. Operating characteristics differed from one kit to another. Good agreement was found using sensitive aCL determination kit and specific anti-beta2GP1 determination kit. Agreement between kits was medium for IgG aCL. 2 x 2 concordance studies showed a group of three aCL kits which were quite homogenous and showed that all anti-beta2GP1 kits formed quite a homogenous group. CONCLUSION: A high degree of variability still persists for aCL antibody determination posing the question of the qualification of commercial or in-house kits and the question of standardization of results. A better concordance is found for high positive results. Good agreement exists for anti-beta2GP1 kits. aCL determination is still needed and should be complemented by anti-beta2GP1 determination.     

在吸毒人群中应用ELISA检测尿液及血液标本中HIV-1抗体结果分析

目的比较利用吸毒人群的尿液和血液标本检测HIV-1抗体结果的一致性.方法对某市强制戒毒所273例吸毒者分别采集其尿液和血液标本,应用ELISA方法分别采用尿液和血液初筛试剂检测尿液和血液标本中的HIV-1抗体.结果 273例中有94例血液标本的HIV-1抗体为阳性,其平行尿液标本中有93例HIV-1抗体为阳性.分析结果表明应用尿液、血液标本检测HIV-1抗体方法的一致性为99.6%.结论采用尿液试剂进行HIV-1抗体检测结果是可靠的,而且是值得大范围推广的.     

Lack of autologous neutralizing antibodies in the cerebrospinal fluid of HIV-1 infected individuals.

The cerebrospinal fluids (CSF) and sera from HIV-1-infected individuals at different clinical stages were monitored for neutralizing activity against CSF-derived HIV-1 isolates. None of the CSF samples and only one of seven serum samples could neutralize the autologous CSF isolate. CSF samples collected one to two years later from the same patients also lacked autologous neutralizing antibodies against these isolates. However, some CSF samples were able to neutralize heterologous CSF isolates albeit in low titers. HIV antibody positive control sera could readily neutralize all of the CSF isolates demonstrating that these isolates were not resistant to neutralization per se. IgG antibodies against the HIV-1 envelope protein and, specifically, against the V3 loop of HIV-1 gp120 (MN) were present in some CSF samples, although the samples lacked neutralizing activity. In summary, this study demonstrates a lack of autologous neutralizing antibodies in CSF samples when assayed against CSF-derived HIV-1 isolates.     

Evaluation of new fourth-generation human immunodeficiency virus antigen and antibody detection assay with enzyme-linked fluorescent immunoassay

We evaluated the fourth-generation HIV screening assay VIDAS HIV DUOII (DUOII) based on ELFA for simultaneous detection of anti-HIV-1 and anti-HIV-2 antibodies and HIV-1 p24 antigen through comparison with other HIV antigen-antibody detection assays. Materials were 1228 HIV-negative specimens, 95 HIV-antibody-positive specimens, and HIV commercial panels. The specificity of DUOII was 99.8% and sensitivity 100%, detecting all of HIV-1 group M subtype A, B, B', C, D, A/E, F, G, B/D, HIV-1 group O, and HIV-2. The sensitivity test to HIV-1 p24 antigen was 5pg/ mL, higher than other assays. DUOII was equivalent to or superior in detecting results earlier than other assays in an evaluation using 10 commercial HIV-1 seroconversion panels of primary infection. DUOII detects anti-HIV IgM antibody, so no negative sample was found in the second window between p24 antigen disappearance and raised anti-HIV IgG antibody. DUOII has sufficient specificity and sensitivity for HIV screening, and detects primary infection sooner than other assays. These results indicate that DUOII is useful and reliable in HIV screening.     

ELISA检测HIV感染者尿液标本中抗HIV-1抗体结果分析

目的利用尿液标本检测抗HIV-1抗体.方法通过ELISA方法检测50例抗HIV-1抗体阳性感染者及100例抗HIV-1抗体阴性对照组尿液中抗HIV-1抗体.结果显示在50例HIV感染者中有49例尿液抗HIV-1抗体阳性,1例阴性;对照组中尿液中均未检测出抗HIV-1抗体,以血液标本为标准,检测尿液抗HIV-1抗体的灵敏性为98.0%,特异性为100%.尿液标本与血液标本检测的一致性达99.3%.结论本实验提示在采集血液标本不便的情况下,可通过尿液抗HIV-1抗体的检测对高危人群的HIV感染情况进行监测和筛查.     

Evaluation of different commercial kits for HIV/HTLV-III EIA

Choice of an ideal, cost-effective and rapid diagnostic test for HIV infection is of immense value in developing countries like India where resources are limited. A number of commercial HIV antibody testing kits are now available with varying sensitivities and specificities. Six different commercial HIV kits namely, Wellcozyme, Flow HIV-TEKG, Abbott HIV EIA, Abbott VIA, Dip-stick EIA and Abbott env/core recombinant EIA were evaluated. Du-Pont Western blot (W.B.) kit was used as gold standard to compare the results. Of the 376 sera from various high-risk individuals screened, Wellcozyme kit yielded 100 per cent concordant results with W.B. Abbott VIA and Abbott env/core also yielded results in confirmation with W.B., excepting the fact that both detected one extra sample positive, which was negative in W.B. Abbott EIA yielded 4 false positive results. Dip-stick kit yielded the maximum number of false positives. The study indicated that 3 kits, namely Wellcozyme, Abbott VIA and Abbott EIA could be used to achieve optimum and acceptable results.     

A critical evaluation of enzyme immunoassay kits for detection of antinuclear autoantibodies of defined specificities. II. Potential for quantitation of antibody content

OBJECTIVE: To analyze the performance of different commercial enzyme immunoassay (EIA) kits for measuring antibody levels of antinuclear antibodies (ANA) specific for double stranded (ds) DNA, SSB/La, Sm, and Scl-70. METHODS: Twenty companies that were known major purveyors of EIA kits for detection of ANA were approached to determine their interest and willingness to participate in this study. The manufacturers were advised that they would be sent coded sera containing mixtures of the Arthritis Foundation/Centers for Disease Control reference reagents, and that they were to use their own test kits to analyze the antibody specificities of these sera and to report the data, in optical density (OD) units, or their equivalent. The analysts were blinded to the concentration of the antibodies and the specificities. RESULTS: Initially, 11 manufacturers out of 20 agreed to participate, but 2 subsequently withdrew. The commercial EIA kits have the potential of being able to quantitate specific autoantibody content to ds-DNA, SSB/La, Sm, and Scl-70. However, certain deficiencies in these kits were also detected, the most obvious being lack of uniformly good performance, with kits of certain manufacturers showing exceptional accuracy in 3 out of 4 of their antibody-specific kits and poor accuracy for a 4th kit. CONCLUSION: It is important for clinicians to appreciate that there is marked inter-manufacturer variation in the performance of EIA kits used as an aid in the diagnosis of systemic rheumatic diseases. Manufacturers need to exercise constant surveillance of kit performance and to provide assurance that such is being done. Improved EIA kits would lend themselves to reliable quantitation of antibody levels in human sera and help to determine whether serial measurement of antibody levels might be useful in monitoring disease activity.