Evaluation of supplemental testing with the Multispot HIV-1/HIV-2 Rapid Test and APTIMA HIV-1 RNA Qualitative Assay to resolve specimens with indeterminate or negative HIV-1 Western blots

BackgroundThe use of Western blot (WB) as a supplemental test after reactive sensitive initial assays can lead to inconclusive or misclassified HIV test results, delaying diagnosis.ObjectiveTo determine the proportion of specimens reactive by immunoassay (IA) but indeterminate or negative by WB that could be resolved by alternative supplemental tests recommended under a new HIV diagnostic testing algorithm.Study designRemnant HIV diagnostic specimens that were reactive on 3rd generation HIV-1/2 IA and either negative or indeterminate by HIV-1 WB from 11 health departments were tested with the Bio-Rad Multispot HIV-1/HIV-2 Rapid Test (Multispot) and the Gen-Probe APTIMA HIV-1 RNA Qualitative Assay (APTIMA).ResultsAccording to the new testing algorithm, 512 (89.8%) specimens were HIV-negative, 55 (9.6%) were HIV-1 positive (including 19 [3.3%] that were acute HIV-1 and 9 [1.6%] that were positive for HIV-1 by Multispot but APTIMA-negative), 2 (0.4%) were HIV-2 positive, and 1 (0.2%) was HIV-positive, type undifferentiated. 47 (21.4%) of the 220 WB-indeterminate and 8 (2.3%) of the 350 WB-negative specimens were HIV-1 positive.ConclusionApplying the new HIV diagnostic algorithm retrospectively to WB-negative and indeterminate specimens, the HIV infection status could be established for nearly all of the specimens. IA-reactive HIV-infected persons with WB-negative results had been previously misclassified as uninfected, and HIV diagnosis was delayed for those with WB-indeterminate specimens. These findings underscore the limitations of the WB to confirm HIV infection after reactive results from contemporary 3rd or 4th generation IAs that can detect HIV antibodies several weeks sooner than the WB.     

Detection and differentiation of HIV-2 using the point-of-care Alere q HIV-1/2 Detect nucleic acid test

BackgroundThe Alere q HIV-1/2 Detect test (Alere Detect) is a rapid point-of-care (POC) nucleic acid test (NAT) that can detect and differentiate HIV-1 and HIV-2 in 25-μL whole blood or plasma samples. The Alere Detect test has been validated for early infant diagnosis of HIV-1 infection, and it is the only POC NAT device currently known to detect HIV-2, which is endemic in West Africa.ObjectivesTo evaluate the sensitivity detecting HIV-2 RNA and the differential performance of the Alere Detect.Study designPlasma samples from non-HIV (n = 4), HIV-1 (n = 22), HIV-2 (n = 111; 29 Group A, 2 Group B) and HIV-1/HIV-2 dually-seropositive (n = 8) participants in Senegal and the United States and HIV-2 reference strains (3 Group A, 1 Group B) were tested by Alere Detect, Abbott RealTime HIV-1 and the University of Washington HIV-2 RNA quantitative (UW HIV-2) assays.ResultsThe Alere Detect correctly differentiated between HIV-1 and HIV-2 in all 80 (100%) patient samples with detectable HIV RNA (n = 20 HIV-1, 60 HIV-2). The overall HIV-2 detection concordance between Alere Detect and the UW HIV-2 assay was 68% (54/80); the concordance improved to 100% (30/30) for samples with HIV-2 RNA >300copies/mL. Neither assay detected HIV-2 RNA in 31 of 111 HIV-2 seropositive samples.ConclusionsThe Alere Detect test is a novel device detecting HIV RNA in clinical samples, and differentiating HIV-1 and HIV-2 with a high level of specificity. It has the potential for use as a rapid HIV-2 NAT-based diagnosis tool in resource-limited settings and to confirm HIV-2 infection for the CDC 4th generation HIV-1/2 diagnostic algorithm.     

Evaluation of Xpert HIV-1 Qual assay for resolution of HIV-1 infection in samples with negative or indeterminate Geenius HIV-1/2 results

BackgroundDiagnosis of HIV infection is a multistage algorithm. Following screening with 4^th generation combination immunoassay, confirmation of HIV infection is performed with an antibody assay that differentiates HIV-1 from HIV-2 infection. In the newly updated algorithm, samples that are nonreactive or indeterminate in the differentiation assay are to be tested with an HIV-1 nucleic acid amplification (NAAT) test for resolution. Xpert HIV-1 Qual is a new NAAT assay approved for the identification of HIV infection in whole and dried blood.ObjectivesTo assess the performance of Xpert HIV-1 Qual supplementary assay in resolving the clinical status of serum samples reactive by 4^th generation immunoassays and indeterminate or negative by Geenius HIV-1/2 confirmatory assay.Study designIn a retrospective study, samples from 97 individuals for whom the true HIV-1 status was already known (by follow-up samples) and which were negative or indeterminate by HIV-1/2 Geenius assay were tested with Xpert Qual HIV-1 assay.ResultsXpert Qual assay correctly classified all 97 samples from HIV-1 positive (n = 49) and negative (n = 48) individuals. The sensitivity and specificity of Xpert Qual when using the true HIV status as a reference were 100% (92.7–100% at 95% confidence interval [CI] and 92.6–100% at 95% CI, respectively).ConclusionsApplying Xpert Qual HIV-1 assay in the new HIV multi-stage diagnostic algorithm correctly classified 100% of HIV-1 infections including 49 from HIV-1 carriers who have not yet seroconverted. With this assay the total time required for acute HIV diagnosis could be significantly reduced.     

Characterization of a monoclonal antibody to a novel glycan-dependent epitope in the V1/V2 domain of the HIV-1 envelope protein,gp120

Recent studies have described several broadly neutralizing monoclonal antibodies (bN-mAbs) that recognize glycan-dependent epitopes (GDEs) in the HIV-1 envelope protein, gp120. These were recovered from HIV-1 infected subjects, and several (e.g., PG9, PG16, CH01, CH03) target glycans in the first and second variable (V1/V2) domain of gp120. The V1/V2 domain is thought to play an important role in conformational masking, and antibodies to the V1/V2 domain were recently identified as the only immune response that correlated with protection in the RV144 HIV-1 vaccine trial. While the importance of antibodies to polymeric glycans is well established for vaccines targeting bacterial diseases, the importance of antibodies to glycans in vaccines targeting HIV has only recently been recognized. Antibodies to GDEs may be particularly significant in HIV vaccines based on gp120, where 50% of the molecular mass of the envelope protein is contributed by N-linked carbohydrate. However, few studies have reported antibodies to GDEs in humans or animals immunized with candidate HIV-1 vaccines. In this report, we describe the isolation of a mouse mAb, 4B6, after immunization with the extracellular domain of the HIV-1 envelope protein, gp140. Epitope mapping using glycopeptide fragments and in vitro mutagenesis showed that binding of this antibody depends on N-linked glycosylation at asparagine N130 (HXB2 numbering) in the gp120 V1/V2 domain. Our results demonstrate that, in addition to natural HIV-1 infection, immunization with recombinant proteins can elicit antibodies to the GDEs in the V1/V2 domain of gp120. Although little is known regarding conditions that favor antibody responses to GDEs, our studies demonstrate that these antibodies can arise from a short-term immunization regimen. Our results suggest that antibodies to GDEs are more common than previously suspected, and that further analysis of antibody responses to the HIV-1 envelope protein will lead to the discovery of additional antibodies to GDEs.     

Th1/Th2 cytokine responses following HIV-1 immunization in seronegative volunteers

The Th1/Th2 profile that follows human vaccination may profoundly influence the subsequent course of disease after infection. However, the ability to detect IL-4 has been limited outside trials of live vaccination. By using methods in which memory effector cells are allowed to antigenically expand by short term culture, followed by low-dose mitogenic stimulation, we have been able to follow the Th1/Th2 profile in HIV-1^?volunteers enrolled in two phase I studies of HIV immunogens (a recombinant gp120 and a multivalent, octomeric V3 loop peptide). Antigen-specific interferon-gamma (IFN-γ) could be detected in primary stimulation, but IL-4 was observed only after antigenic expansion and restimulation. In both of these studies the responses after initial immunizations were dominated by IFN-γ, with IL-4 appearing only after multiple rounds of immunization, and IL-4 was temporally related to antibody production. Concomitant with the IL-4 production, the amount of supernatant IFN-γ declined. Antigen-specific IL-10 was not detected in either study. Such techniques, which have been shown to correlate with outcomes in immunotherapy, may prove useful as future surrogates of human vaccine response.     

HIV-1 Tat-Based Vaccines: An Overview and Perspectives in the Field of HIV/AIDS Vaccine Development

The HIV epidemic continues to represent one of the major problems worldwide, particularly in the Asia and Sub-Saharan regions of the world, with social and economical devastating effects. Although antiretroviral drugs have had a dramatically beneficial impact on HIV-infected individuals that have access to treatment, it has had a negligible impact on the global epidemic. Hence, the inexorable spreading of the HIV pandemic and the increasing deaths from AIDS, especially in developing countries, underscore the urgency for an effective vaccine against HIV/AIDS. However, the generation of such a vaccine has turned out to be extremely challenging. Here we provide an overview on the rationale for the use of non-structural HIV proteins, such as the Tat protein, alone or in combination with other HIV early and late structural HIV antigens, as novel, promising preventative and therapeutic HIV/AIDS vaccine strategies.     

Shortening of the diagnostic window with a new combined HIV p24 antigen and anti-HIV-1/2/O screening test

Because antibodies to the human immunodeficiency virus (HIV) are absent in the very early phase of HIV infection, there remains a slight residual risk for HIV transmission by blood donations by viremic but antibody negative donations. To shorten the diagnostic window between infection and the detection of antibodies, Enzygnost® HIV Integral (Dade Behring, Germany) was developed. With this new test, HIV p24 antigen and HIV antibodies can be detected simultaneously in a single test. In a multicenter study the new screening assay has been compared with various tests that detect only HIV antibodies or HIV p24 antigen and with assays which permit a simultaneous detection of HIV antigen and HIV antibodies. The new assay showed 100% sensitivity for the detection of antibodies to HIV-1, groups M (n=1102) and O (n=55), and HIV-2 (n=289). In 23 out of 52 seroconversion panels, seroconversion was detected 2–18 days earlier with the new combined antigen/antibody test compared to single antibody tests. All samples from a viral load panel (n=451), all samples containing p24 antigen (n=302), and all but one of the cell culture supernatants (n=38) infected with various HIV-1 subtypes or HIV-2 were identified reliably by the new test. The specificity of the assay for 4002 unselected blood donors was 99.78% initially and 99.80% after retesting. Potentially interfering factors had no systematic influence on specificity. By testing for p24 antigen, which is present prior to the onset of antibody production in some cases of recent HIV infection, the new assay reduces the diagnostic window as compared to third generation screening assays, thus permitting an earlier diagnosis of HIV infection.     

Replication competent molecular clones of HIV-1 expressing Renilla luciferase facilitate the analysis of antibody inhibition in PBMC

Effective vaccine development for human immunodeficiency virus type 1 (HIV-1) will require assays that ascertain the capacity of vaccine immunogens to elicit neutralizing antibodies (NAb) to diverse HIV-1 strains. To facilitate NAb assessment in peripheral blood mononuclear cell (PBMC)-based assays, we developed an assay-adaptable platform based on a Renilla luciferase (LucR) expressing HIV-1 proviral backbone. LucR was inserted into pNL4-3 DNA, preserving all viral open reading frames. The proviral genome was engineered to facilitate expression of diverse HIV-1 env sequences, allowing analysis in an isogenic background. The resulting Env-IMC-LucR viruses are infectious, and LucR is stably expressed over multiple replications in PBMC. HIV-1 neutralization, targeting TZM-bl cells, was highly correlative comparing virus (LucR) and cell (firefly luciferase) readouts. In PBMC, NAb activity can be analyzed either within a single or multiple cycles of replication. These results represent advancement toward a standardizable PBMC-based neutralization assay for assessing HIV-1 vaccine immunogen efficacy.     

Diagnosing acute HIV infection: The performance of quantitative HIV-1 RNA testing (viral load) in the 2014 laboratory testing algorithm

New recommendations for laboratory diagnosis of HIV infection in the United States were published in 2014. The updated testing algorithm includes a qualitative HIV-1 RNA assay to resolve discordant immunoassay results and to identify acute HIV-1 infection (AHI). The qualitative HIV-1 RNA assay is not widely available; therefore, we evaluated the performance of a more widely available quantitative HIV-1 RNA assay, viral load, for diagnosing AHI. We determined that quantitative viral loads consistently distinguished AHI from a false-positive immunoassay result. Among 100 study participants with AHI and a viral load result, the estimated geometric mean viral load was 1,377,793 copies/mL.     

Distribution of two HIV-1-resistant polymorphisms (SDF1-3′A and CCR2-64I alleles) in the Polish population

Chemokine receptors (CCR2 and CXCR4) are used as coreceptors for entry of human immunodeficiency virus (HIV) into the target cells. Mutations in CCR2 (CCR2-64I) and stromal-derived factor SDF1 (SDF1-3′A), the primary ligand for CXCR4, exhibited a protective effect against the onset of acquired immune deficiency syndrome (AIDS). The frequency of the SDF1-3′A and CCR2-64I alleles were determined in blood donors from 16 provinces, covering the entire territory of Poland. Of 1063 individuals, 274 (25.8%) were carriers of the SDF1-3′A allele; 36 of them (3.4%) were homozygotes (SDF-3′A/A) while 238 (22.4%) were heterozygotes (SDF-3′G/A), resulting in a 14.6% frequency of the SDF1-3′A allele. Moreover, in the same group of individuals, 234 (22.0%) carried the CCR2-64I allele; 6 of them (0.6%) were homozygotes (CCR2-64I/I), and 228 (21.4%) were heterozygotes (CCR2-64V/I), resulting in an 11.3% frequency of the CCR2-64I allele. The highest frequencies of the SDF1-3′A allele were found in the northeastern provinces and in one of the western provinces of Poland. In contrast, allelic frequencies of CCR2-64I varied slightly among different provinces. The different pattern of prevalence of the SDF1-3′A and CCR2-64I alleles in Poland might suggest that the CCR2-64I allele was spread much earlier than the SDF1-3′A allele in the population of Poland. Received: March 25, 2002 / Accepted: July 29, 2002 Acknowledgments We thank the directors of the Transfusion Centers from the 16 administrative provinces of Poland for providing venous blood samples. This research was supported by grant no. 6PO5B09221 from the State Committee for Scientific Research (KBN) and grant no. 501-1-08-05 from K. Marcinkowski University of Medical Sciences, Poznań. Correspondence to:P.P. Jagodzinski     

HIV抗体快速检测试剂的临床评价

目的对注册前的HIV抗体快速检测试剂的质量进行临床评价。方法用不同的评价试剂检测440份健康献血员样品、300份HIV抗体强阳性样品以及264份HIV感染高危人群样品，并分别计算其特异性和敏感性。结果17家注册前试剂检测300份HIV抗体强阳性样品的敏感性为100％；检测440份健康献血员样品的特异性为97．7％-100％；检测264份HIV感染高危人群样品的特异性为59．1％-100％，敏感性为70．3％-95．1％。结论不同试剂之间存在敏感性和特异性的差异，而且HIV感染的高危自然人群来源的样品有助于客观地反应试剂的质量差异。     

抗HIV-1核心抗原p24单克隆抗体的制备及特性的初步鉴定

目的 :建立分泌抗HIV 1p2 4单克隆抗体 (mAb)的杂交瘤细胞株 ,并对其特性进行初步鉴定。方法 :以纯化的基因工程制备的p2 4抗原免疫BALB/c小鼠 ,取免疫小鼠的脾细胞与Sp2 /0骨髓瘤细胞融合 ,经HAT、HT选择培养及有限稀释法进行克隆化后 ,用间接ELISA法及Dotblot对其进行筛选和特性鉴定。结果 :筛选到 2株可分泌抗HIV 1p2 4mAb的杂交瘤细胞 ,其腹水效价为 1×10 -5,亲和力为 1.7× 10 4～ 1.8×10 4mol/L ,mAb的Ig亚类均为IgG1。两株mAb与HBcAg、HCVRNA阳性血清及HIVgp4 1等均无交叉反应 ,只与HIV 1p2 4抗原阳性血清产生特异反应。结论 :成功地建立了 2株可分泌抗HIV 1p2 4mAb的杂交瘤细胞 ,为进一步研制HIV 1p2 4抗原的ELISA检测试剂盒奠定了基础     

Comparative performance of the new Aptima HIV-1 Quant Dx assay with three commercial PCR-based HIV-1 RNA quantitation assays

BackgroundQuantitative measurement of HIV-1 RNA levels in plasma (‘viral load’) plays a central role in clinical management. The choice of assay platform can influence results and treatment decisions.ObjectiveTo compare the analytical performance of the new TMA-based Hologic Aptima^® HIV-1 Quant Dx assay with that of three PCR-based assays: Abbott RealTime HIV-1, Qiagen Artus^® HI Virus-1 QS-RGQ, and Roche CAP/CTM HIV-1 Test v2.Study designAssay performance was evaluated using Acrometrix HIV-1 RNA Standard panels; the 3rd WHO HIV-1 RNA International Standard (12–500 copies/ml; 6 dilutions; 9 replicates); and plasma samples from 191 HIV-positive patients.ResultsAptima showed high (>0.99) precision, accuracy and concordance with the Acrometrix Standards across a wide dynamic range (2.0–6.7 log₁₀ copies/ml). Variance caused up to 2.1 (Aptima), 1.7 (RealTime), 7.5 (Artus), and 1.9 (CAP/CTM) fold changes in the International Standard quantifications at 50–500 copies/ml. HIV-1 RNA detection rates in plasma samples were 141/191 (74%), 119/191 (62%), 108/191 (57%), and 145/191 (76%) for Aptima, RealTime, Artus and CAP/CTM, respectively. For categorising samples either side of 50 copies/ml, Aptima had excellent agreement with RealTime (kappa 0.92; 95% CI 0.87–0.98); lowest agreement was with Artus (kappa 0.79; 95%CI 0.70–0.88). Aptima quantifications were mean 0.12 and 0.06 log₁₀ copies/ml higher compared with RealTime and CAP/CTM, respectively, and 0.05 log₁₀ copies/ml lower compared with Artus. Limits of agreement were narrowest when comparing Aptima to RealTime.ConclusionsThe new Aptima HIV assay is sensitive, precise, and accurate. HIV assays exhibit discordance at low HIV-1 RNA copy numbers.     

Differential incorporation of uracil DNA glycosylase UNG2 into HIV-1, HIV-2, and SIV(MAC) viral particles

We have previously reported that the host uracil DNA glycosylase UNG2 enzyme is incorporated into HIV-1 virions via a specific association with the viral integrase (IN) domain of Gag-Pol precursor. In this study, we investigated whether UNG2 was packaged into two phylogenetically closely related primate lentiviruses, HIV-2(ROD) and SIV(MAC239). We demonstrated by GST-pull-down and coprecipitation assays that INs from HIV-1, HIV-2(ROD), and SIV(MAC239) associated with UNG2, although the interaction of UNG2 with HIV-2(ROD) IN and SIV(MAC239) IN was less strong than with HIV-1 IN. We then showed by Western blotting that highly purified HIV-2 and SIV(MAC) viral particles did not incorporate host UNG2, contrasting with the presence of UNG2 in HIV-1 viral particles. Finally, we showed that HIV-1/SIV chimeric viruses in which residues 6 to 202 of HIV-1 IN were replaced by the SIV counterpart were impaired for packaging of UNG2, indicating that the incorporation of host UNG2 into viral particles is the hallmark of the HIV-1 strain. Moreover, we found that HIV-1/SIV IN chimeric viruses were deficient for viral propagation.     

HIV-1膜蛋白GP120V1/V2区域的真核表达、纯化和鉴定

目的:真核表达北美HIV-1分离株BAL和中国分离株CNE1两种毒株的V1V2,并纯化、鉴定其生物活性,为血清学分析鉴别HIV-1感染病人抗体反应及性质提供实验基础。方法:本研究将HIV-1北美分离株BAL和中国分离株CNE1两种毒株的V1V2基因序列定向克隆到多系统表达载体pTriEx-3 Hygro vector(Merck&Co.,Inc.)中,构建了表达质粒,并将表达质粒瞬时转染293T细胞,144小时后收获上清液,经浓缩、纯化后,SDS-PAGE电泳,Western blot检测蛋白的表达,ELISA检测其与HIV-1阳性病人血清的反应性。结果:经SDS-PAGE电泳、Western blot、ELISA方法证实确实得到了有免疫反应活性的V1V2蛋白,从表观分子量判断,表达的V1V2蛋白被糖基化修饰。使用V1V2蛋白作为抗原,分析发现中国HIV-1阳性病人体内比较广泛的存在着V1V2的抗体,为血清学的分析奠定了实验基础。     

中国HIV-1感染疾病长期不进展者CCR2-64I、SDF1-3’A和CCR5Δ32的基因变异研究

目的 探讨CCR2-641、SDF1-3’A、CCR5Δ32基因变异对中国HIV—1感染疾病长期不进展者（long-term nonprogressors，LTNPs）疾病进程的影响。方法 收集17例中国HIV-1感染LTNPs和39例中国HIV-1感染疾病典型进展者（typical progressors，TPs）的抗凝全血标本，用全自动核酸提取仪提取基因组DNA，采用PCR／RFLP技术对CCR2、SDF1、CCR5基因进行检测分析。结果 LTNP组的CCR2-64I、SDF1-3’A基因突变率分别为50％和62．5％，TP组的CCR2-64I和SDF1-3’A基因突变率分别为23．08％、33．33％，LTNP组CCR2—64I、SDF1-3’A基因突变率明显高于TP组（P〈0．05）；LTNP组有1例CCR5Δ32杂合突变，未发现纯合变异，而TP组未发现CCR5Δ32突变。结论 CCR2-64I、SDF1-3’A和CCR5Δ32基因突变可能是中国HIV-1感染者疾病长期不进展的保护性因素之一。     

Comparison of cervicovaginal humoral immunity in clinically asymptomatic (CDC Al and A2 category) patients with HIV-1 and HIV-2 infection

Paired sera and cervicovaginal secretions (CVS) from 11 HIV-1- and 11 HIV-2-infected women, all clinically asymptomatic (CDC A1 and A2 categories), were analyzed for total IgG, IgA, albumin (HSA), IgG, and IgA antibodies toenvencoded surface glycoproteins of HIV-1 (gp160) and of HIV-2 (gp105), by comparison to 15 age-matched healthy controls. Secretion rates of IgG and IgA into CVS were evaluated by calculation of their relative coefficients of excretion (RCE) by reference to HSA. Cervicovaginal production of anti-HIV antibodies was evaluated by comparison between specific antibody activities of IgG and of IgA to HIV in CVS and in sera. In HIV-1-infected women, total IgG and IgA in CVS were, respectively, 6- and 4-fold increased, whereas the secretion rate of total IgG was 2.1-fold increased and that of total IgA was 2.5-fold reduced. In contrast, total IgG and IgA as well as their secretion rates were normal in HIV-2-infected women. In HIV-1- but not in HIV-2-infected women, HSA levels in cervicovaginal washings were twofold increased, demonstrating alteration of the mucosal barrier in HIV-1 infection. In HIV-1-infected patients, IgG and IgA to gpl60 were detected in all sera and CVS. In HIV-2-infected patients, IgG to gp105 was detected in all sera and CVS, whereas IgA to gp105 could be detected in only half of sera and one-third of CVS. Cross-reactivity by IgG and/or IgA to HIV-1 or HIV-2 against the surface glycoprotein of the other HIV type was observed in sera as well as in CVS, and more frequently in HIV-2- than in HIV-1-infected women. Finally, the mean specific activities of IgG and of IgA to gp160 or gp105 were higher in CVS than in sera, evidencing a possible local synthesis of both isotypes in HIV-1 as well as in HIV-2 infections. As early as the asymptomatic stages, HIV-1 affects the cervicovaginal mucosa more than HIV-2 does, suggesting higher viral replication within the female genital tract in HIV-1 infection than in HIV-2 infection.     

Anti-B7-1/B7-2 antibody elicits innate-effector responses in macrophages through NF-kappaB-dependent pathway

Blocking T cell co-stimulatory signals by anti-B7-1/B7-2 mAb is an attractive approach to treat autoimmune diseases. However, anti-B7-1/B7-2 mAb treatment is known to exacerbate autoimmune diseases through mechanisms not fully understood. Tumor necrosis factor alpha (TNF-alpha) and reactive oxygen species (ROS) also play important roles in determining the clinical outcome of autoimmune diseases. In this study, we demonstrate that the anti-B7-1 and the anti-B7-2 mAbs activate macrophages for higher induction of TNF-alpha and other effector responses such as bacterial cytotoxicity and production of ROS. Nuclear factor-kappaB (NF-kappaB) was found to be increased with anti-B7-1/B7-2 mAb treatment. Inhibition of NF-kappaB activity by over-expression of phosphorylation-defective I-kappaB alpha in anti-B7-1/B7-2 mAb-treated macrophages decreased TNF-alpha production. These data indicate that anti-B7-1 and anti-B7-2 mAbs can trigger innate-effector responses in macrophages by activating NF-kappaB-signaling pathway. Our results suggest that the B7 molecules are not only essential for induction of adaptive immune responses but also play roles in activation of innate immune responses.     

Comparison of HIV-1 detection in plasma specimens and dried blood spots using the Roche COBAS Ampliscreen HIV-1 test in Kisumu, Kenya

The World Health Organization recommends screening donor blood for HIV in centralized laboratories. This recommendation contributes to quality, but presents specimen transport challenges for resource-limited settings which may be relieved by using dried blood spots (DBS). In sub-Saharan Africa, most countries screen donor blood with serologic assays only. Interest in window period reduction has led blood services to consider adding HIV nucleic acid testing (NAT). The U.S. Food and Drug Administration (FDA) mandates that HIV-1 NAT blood screening assays have a 95% detection limit at or below 100 copies/ml and 5000 copies/ml for pooled and individual donations, respectively. The Roche COBAS Ampliscreen HIV-1 test, version 1.5, used for screening whole blood or components for transfusion, has not been tested with DBS. We compared COBAS Ampliscreen HIV-1 RNA detection limits in DBS and plasma. An AIDS Clinical Trials Group, Viral Quality Assurance laboratory HIV-1 standard with a known viral load was used to create paired plasma and DBS standard nine member dilution series. Each was tested in 24 replicates with the COBAS Ampliscreen. A probit analysis was conducted to calculate 95% detection limits for plasma and DBS, which were 23.8 copies/ml (95% CI 15.1-51.0) for plasma and 106.7 copies/ml (95% CI 73.8-207.9) for DBS. The COBAS Ampliscreen detection threshold with DBS suggests acceptability for individual donations, but optimization may be required for pooled specimens.