中国HIV-1B''/C亚型感染者对自身病毒中和作用与疾病进展关系的研究

目的：探讨中国HIV-1 B’/C亚型感染者对自身病毒中和作用与疾病进展的关系。方法：将24例HIV-1 B’/C感染者自身原代病毒与同期和6个月自身血浆作用后,感染正常PBMC,培养7天测定p24抗原浓度,以正常人血浆加病毒悬液为对照。以抑制50%对照孔p24浓度的血浆最高稀释倍数的倒数计算中和抗体滴度,中和抗体滴度≥8倍为具有中和作用。结果：在同期血浆中和自身病毒试验中,3例缓慢进展者（SP）均具有中和作用,HIV组仅4例（4/21）具有中和作用,SP组中和抗体滴度明显高于HIV组。在6个月血浆中和自身病毒试验中,SP组中和抗体滴度明显增加,HIV组12例具有中和作用,SP组中和抗体滴度明显高于HIV组。中和抗体滴度与病毒载量呈明显的负相关。结论：疾病缓慢进展的HIV-1 B’/C亚型感染者对自身病毒中和作用明显高于HIV组,提示中和抗体在延缓疾病进程中发挥重要作用。     

HIV-1B′亚型毒株抵抗VRC01抗体中和作用的机制研究

目的:探讨具有广谱中和活性的患者DRVI01血浆来源的HIV-1B′亚型毒株抵抗VRC01抗体中和的机制。方法:比较同期感染相同亚型且对VRC01抗体敏感的病毒序列,结合文献报道筛选可能影响VRC01中和作用的关键氨基酸,通过定点突变、不同来源膜蛋白序列交换,验证这些位点氨基酸对VRC01抗体中和作用的影响。结果:位于...     

HIV-1自然感染中的中和抗体反应

中和抗体(Nab)可以防止I型人类免疫缺陷病毒(HIV-1)侵入靶细胞.HIV-1感染数周后即可诱导产生Nab,这些早期抗体只能特异性地中和自体病毒但不能中和异源性病毒.在一些慢性感染者体内则可以检测到可同时中和同源性和异源性病毒的广谱中和抗体(BNab).BNab的靶点通常位于包膜蛋白的保守区域.HIV-1 BNab的产生还受到病毒变异及结构遮盖等因素的限制,同时Nab的中和广度与病毒载量具有相关性.     

HIV-1准种的变化与疾病进展关系的研究

目的　研究HIV 1准种的变化对疾病进展的影响。方法　PCR方法扩增HIV 1V3～V5区片段 ,采用HMA(异源双链泳动分析 )的方法分析 4 8例HIV/AIDS准种的变化 ,并结合HIV/AIDSCD4 T淋巴细胞计数及病毒载量的结果分析HIV 1准种的变化对疾病进程的影响。结果　在不同的疾病状态下 ,体内病毒变异是不相同的 ,在体内CD4 T淋巴细胞计数较高 ,血浆病毒载量低的个体内 ,病毒毒株有很强的变异特征 ,体内具有很高的准种复杂度 ;而在CD4 细胞数很低 ,病毒载量较高的个体 ,病毒基因变异较少 ,病毒准种较为单一。结论　HIV 1准种的变化与疾病进展相关。     

HIV-1病毒感染因子基因克隆、表达、纯化及其抗体制备的研究

目的制备HIV-1病毒感染因子(Vif)及其抗体。方法用PCR技术从HIV-1NL4·3cDNA质粒中扩增病毒感染因子(vif)基因,vif基因全长为579nt(核苷酸),翻译成含192个氨基酸的蛋白质。将测序鉴定过的vif基因克隆到原核表达载体pET-32a上,以包涵体的形式在大肠埃希菌BL21(DE3)中高效表达,Vif蛋白C端融合6×His标签便于纯化及鉴定。应用酶切鉴定、SDS-PAGE及WesternBlot等方法确保基因片段的正确性及表达蛋白的特异性。间接ELISA法测定兔多克隆抗体滴度。结果成功地获得了高纯度的Vif融合蛋白,纯度可达80%以上。用其制备多克隆抗体滴度可达1∶204800。结论获得高纯度的Vif融合蛋白及其高效价的抗体。     

中国HIV-1病毒分离株的生物学特性与疾病进展关系的研究

目的　从HIV AIDS患者应用微量全血法分离中国HIV 1毒株 ,研究HIV 1的生物学特性与HIV AIDS疾病进展相关性。方法　建立微量全血法 ,从HIV AIDS全血标本中分离 17株HIV 1病毒分离株 ;检测这 17株病毒分离株嗜性和复制动力。结果　从 2 6例HIV AIDS病例中分离出HIV 1病毒 ,分离率为 6 5 .4 % (17 2 6 ) ,其中 17例HIV 1感染者的病毒分离率为 5 2 .9% (9 17) ,均为巨噬细胞嗜性 (M嗜性 ,NSI) ;9例AIDS患者的HIV 1病毒分离率为 88.9% (8 9) ,其中 7株为T细胞嗜性 (T嗜性 ,SI) ,1株为巨噬细胞嗜性。通过检测P2 4抗原确定 17株HIV 1病毒分离株的复制动力。在分离到的 17株HIV 1中 ,SI型病毒分离株与AIDS组显著相关 (P <0 .0 5 ) ;AIDS期的病毒分离株的复制动力明显高于HIV感染期 (P <0 .0 5 )。结论　微量全血法可用于病毒分离。 17株分离株的HIV 1复制动力与CD4 + T淋巴细胞计数呈线性负相关 ,与病毒载量呈正相关。     

中国HIV-1 B'/C亚型感染者对异体病毒中和作用与疾病进展关系研究

目的 探讨中国HIV-1 B'/C亚型感染者对异体病毒中和作用与疾病进展的关系.方法 根据CD4 T淋巴细胞数量和有尤临床症状将HIV-1 B'/C亚型感染者分为HIV慢性感染组和AIDS组.将HIV-1感染者血清稀释(1/10～1/320)后,与在基因结构特点上同源性很低的3株HIV-1作用,以检测其中和作用.同时以正常人血清加病毒悬液为对照孔,能够抑制对照孔50%病毒复制的血清为中和作用阳性.将某个HIV-1感染者血浆能够中和异体病毒的个数占3个异体病毒的百分率定义为HIV-1感染者中和异体病毒的宽度;将某个HIV-1感染者血浆中和3个异体病毒抗体滴度的几何平均滴度定义为HIV-1感染者中和异体病毒的强度.结果 HIV-1慢性感染组与AIDS组之间中和异体病毒的宽度和强度差异有统计学意义,HIV-1慢性感染组显著高于AIDS组.HIV-1慢性感染组中和异体病毒的宽度和强度与病毒载量呈正相关,而AIDS组巾和异体病毒的宽度和强度与病毒载量没有显著的相关性.HIV-1慢性感染组和AIDS组中和异体病毒的宽度和强度与CD4 T淋巴细胞数均没有显著的相关性.结论 中国HIV-1B'/C亚型感染者不同疾病进展阶段针对异体病毒中和作用能力不同,HIV慢性感染组显著高于AIDS组,当疾病进展到AIDS期时,失去对异体病毒的中和作用,提示针对异体病毒的中和抗体与疾病进程有关.     

中国HIV/AIDS患者保守表位的2F5抗体与疾病进展关系

目的 研究中国HIV/AIDS患者gp41保守表位中和抗体2F5与疾病进程的关系.方法 应用合成4(ELDKWA)-C24肽及gp41抗原肽包被96孔酶标板,ELISA方法检测特异性抗体水平.提取正常人外周血单个核细胞(PBMC),应用HIV-1 SF33毒株进行病毒多轮感染PBMC中和试验.结果 缓慢进展者(slow progressor,SP)的2F5样中和抗体水平显著高于典型进展者(typical progressor,TP)(P<0.05);2F5样中和抗体水平与gp41特异性抗体水平正相关(r=0.406,P<0.05).结论 中国HIV.-缓慢进展者体内具有高水平的2F5样抗体,2F5抗体可能是疾病不进展的保护性因素之一.     

基线极高HIV-1 RNA水平对初治HIV-1感染者外周血total HIV-1 DNA的影响

目的:观察基线HIV-1 RNA > 50万copies/mL的HIV-1感染者,在高效抗反转录病毒治疗（highly active antiretroviral therapy,HAART）前后外周血totalHIV-1 DNA的变化。方法:从国家十二五科技重大专项课题中选取基线HIV-1 RNA > 50万copi...     

Permissive residues within the minimal epitopes of neutralizing monoclonal antibodies to the V3 loop of HIV-1

Neutralizing monoclonal antibodies (mAb) specific for the third variable (V3) domain of gp120, the HIV-1 surface envelope protein, are mainly isolate specific. We have studied the composition and the permissivity of the minimal epitopes interacting with two of these, the 110-A and 19.26.4 mAb, which are strictly LAI isolate specific. Screening a hexapeptide phage library displayed on the surface of filamentous phage with the 110-A mAb has allowed selection of 49 phage sequences, permitting the definition of a consensus sequence. Based on this sequence, substituted synthetic peptides were prepared and used in binding assays. Our results show that both mAb interact with the same narrow region (316–320) of the V3 domain. The minimal epitope of the 110-A mAb was identified as a five amino acid sequence, Hy x R G p, where Hy represents any non-aromatic hydrophobic amino acid. By contrast, the minimal epitope of the 19.26.4 mAb was identified as x Q Pos G P, where Pos is any positively charged amino acid. Core residues of the epitope, critical for the binding to the mAb (written in uppercase letters), were set apart from permissive amino acid positions that tolerate substitutions (written in lowercase letters). Interestingly, the identified core residues Q_2/317 (19.26.4 mAb) and R_3/318 (110-A mAb) do not tolerate substitution and correspond to the QR insertion in the V3 domain, characteristic of the LAI isolate as compared to other isolates. This result may explain the strict isolate specificity of most anti-V3 LAI mAb. The two epitopes have totally different patterns of permissivity; thus, the effect of substitutions will differ depending on the mAb involved in the interaction. This suggests that the diversity of the antibody response is high enough to delay the emergence of HIV-1 variants resistant to neutralization by V3-specific antibodies.     

Assessment of antibody responses against gp41 in HIV-1-infected patients using soluble gp41 fusion proteins and peptides derived from M group consensus envelope

Human immunodeficiency virus type 1 (HIV-1) transmembrane glycoprotein gp41 is targeted by broadly-reactive neutralizing antibodies 2F5 and 4E10, making it an attractive target for vaccine development. To better assess immunogenic properties of gp41, we generated five soluble glutathione S-transferase fusion proteins encompassing C-terminal 30, 64, 100, 142, or 172 (full-length) amino acids of gp41 ectodomain from M group consensus envelope sequence. Antibody responses in HIV-1-infected patients were evaluated using these proteins and overlapping peptides. We found (i) antibody responses against different regions of gp41 varied tremendously among individual patients, (ii) patients with stronger antibody responses against membrane-proximal external region exhibit broader and more potent neutralizing activity, and (iii) several patients mounted antibodies against epitopes that are near, or overlap with, those targeted by 2F5 or 4E10. These soluble gp41 fusion proteins could be an important source of antigens for future vaccine development efforts.     

Use of broadly neutralizing antibodies for HIV-1 prevention

Antibodies have a long history in antiviral therapy, but until recently, they have not been actively pursued for HIV-1 due to modest potency and breadth of early human monoclonal antibodies (MAbs) and perceived insurmountable technical, financial, and logistical hurdles. Recent advances in the identification and characterization of MAbs with the ability to potently neutralize diverse HIV-1 isolates have reinvigorated discussion and testing of these products in humans, since new broadly neutralizing MAbs (bnMAbs) are more likely to be effective against worldwide strains of HIV-1. In animal models, there is abundant evidence that bnMAbs can block infection in a dose-dependent manner, and the more potent bnMAbs will allow clinical testing at infusion doses that are practically achievable. Moreover, recent advances in antibody engineering are providing further improvements in MAb potency, breadth, and half-life. This review summarizes the current state of the field of bnMAb protection in animal models as well as a review of variables that are critical for antiviral activity. Several bnMAbs are currently in clinical testing, and we offer perspectives on their use as pre-exposure prophylaxis (PrEP), potential benefits beyond sterilizing immunity, and a discussion of future approaches to engineer novel molecules.     

High titer HIV-1 V3-specific antibodies with broad reactivity but low neutralizing potency in acute infection and following vaccination

Identifying the earliest neutralizing antibody specificities that are elicited following infection or vaccination by HIV-1 is an important objective of current HIV/AIDS vaccine research. We have shown previously that transplantation of HIV-1 V3 epitopes into an HIV-2 envelope (Env) scaffold provides a sensitive and specific means to detect and quantify HIV-1 V3 epitope specific neutralizing antibodies (Nabs) in human sera. Here, we employ this HIV-2/HIV-1 V3 scaffolding strategy to study the kinetics of development and breadth of V3-specific Nabs in longitudinal sera from individuals acutely infected with clade C or clade B HIV-1 and in human subjects immunized with clade B HIV-1 immunogens. HIV-2/HIV-1 chimeras containing V3 sequences matched to virus type (HIV-2 or HIV-1), subtype (clade B or C), or strain (autologous or heterologous) were used as test reagents. We found that by 3-8 weeks post infection, 12 of 14 clade C subjects had a median IC₅₀ V3-specific Nab titer of 1:700 against chimeric viruses containing a heterologous clade C V3. By 5 months post-infection, all 14 subjects were positive for V3-specific Nabs with median titers of 1:8000 against heterologous clade C V3 and 1:1300 against clade B V3. Two acutely infected clade B patients developed heterologous clade B V3-specific Nabs at titers of 1:300 and 1:1800 by 13 weeks of infection and 1:5000 and 1:11000 by 7 months of infection. Titers were not different against chimeras containing autologous clade B V3 sequences. Each of 10 uninfected normal human volunteers who were immunized with clade B HIV-1 Env immunogens, but none of five sham immunized control subjects, developed V3-specific Nabs titers as high as 1:3000 (median 1:1300; range 1:700-1:3000). None of the HIV-1 infected or vaccinated subjects had antibodies that neutralized primary HIV-1 virus strains. These results indicate that high-titer, broadly reactive V3-specific antibodies are among the first to be elicited during acute and early HIV-1 infection and following vaccination but these antibodies lack neutralizing potency against primary HIV-1 viruses, which effectively shield V3 from antibody binding to the functional Env trimer.     

Neutralizing antibodies mechanism of neutralization and protective activity against HIV-1

The role of the humoral immune response in prevention against HIV-1 infection is still incompletely understood. However, neutralizing antibodies to certain epitopes on HIV-1 envelope glycoproteins inhibit HIV-1 infection in vitro and in vivo. Passive administration of these antibodies by themselvesor in combination completely protected hu-PBL-SCID mice or macaques from intravenous, vaginal, as well as maternal-fetal mucosal transmission. All these studies provide direct experimental evidence that neutralizing antibodies are potentenough to prevent HIV infection, and strongly suggest that neutralizing-antibody-based vaccines could provide effective protection against HIV-1, despite the potent action of CTLs. Some neutralizing epitopes have been defined in vitro and in vivo. Unfortunately, none of the neutralizing-antibody-based candidate vaccines has been demonstrated to induce enough protective activity. Weak antigenicity and immunogenicity of neutralizing epitopes on native or recombinant proteins and other factors made it difficult to induce neutralizing-epitope-specific antibody responses in vivo enough to prevent against primary isolates. Recent studies indicated that HIV-1 variations resulted in escape from neutralization or the CTL responses, which may be the principal challenge for HIV-1 prevention. Epitope vaccine as a new strategy activating both arms of the immune system, namely, using the “principal neutralizing epitopes” and the CTL epitopes in combination, should provide new hope for developing an effective vaccine to halt the HIV-1 epidemic.     

慢性HIV-1感染人群血浆不同中和能力及与有关因素的研究

目的 探讨安徽省既往献血的HIV慢性感染人群血浆中和能力及其与CD4、病毒载量的关系.方法 从安徽省既往献血的294位HIV慢性感染人群静脉抽血,EDTA抗凝后进行血浆和外周血单个核细胞(PBMC)的分离、CD4和病毒载量的检测,采用拥有共享序列的临床分离病毒1597株和实验室株SF33病毒两种病毒分别做血浆的中和试验.用200TCID50病毒感染TZM-bl细胞,通过加入不同稀释度血浆,用Luciferase Assay System检测血浆的中和能力并计算中和50%的病毒进入细胞的血浆浓度(EC50).结果 294位患者血浆针对HIV-1实验株SF33和临床分离株1597的中和能力间差异有统计学意义(P<0.05),针对实验株的中和能力明显高于临床分离株,91%患者血浆对HIV-1实验株SF33具有一定的中和抗体,其中EC50>500的抗体水平较高的血浆占33%,对临床分离株1597的中和抗体阳性率为79%,其中EC50>500的占7%.方差分析显示,血浆中和能力在CIM不同水平之间没有显著差异.294位HIV-1B'亚型感染的血浆病毒载量(1g)平均为4.40(2.60～6.46).方差分析显示,血浆对SF33的中和能力在不同病毒载量水平之间有显著差异,病毒载量不同的各组血浆针对1597病毒的中和能力之间差异无统计学意义.经Spearman's B相关分析,对SF33株的中和水平与病毒载量呈正相关,对1597株的中和水平与病毒载量的相关性没有统计学意义.在病毒载量1g<4的患者中,10.53%血浆样品的EC50高于500;在病毒载量1g≥5的患者中,6.46%血浆样品的EC50高于500.结论 HIV-1慢性感染人群的血浆对实验株SF33的中和能力随着病毒复制能力的提高而增加,但对临床分离株1597的中和能力未见相关性.     

Cross-clade neutralizing antibodies against HIV-1 induced in rabbits by focusing the immune response on a neutralizing epitope

Studies were performed to induce cross-clade neutralizing antibodies (Abs) by testing various combinations of prime and boost constructs that focus the immune response on structurally-conserved epitopes in the V3 loop of HIV-1 gp120. Rabbits were immunized with gp120 DNA containing a V3 loop characterized by the GPGR motif at its tip, and/or with gp120 DNA with a V3 loop carrying the GPGQ motif. Priming was followed by boosts with V3-fusion proteins (V3-FPs) carrying the V3 sequence from a subtype B virus (GPGR motif), and/or with V3 sequences from subtypes A and C (GPGQ motif). The broadest and most consistent neutralizing responses were generated when using a clade C gp120 DNA prime and with the V3_B-FP boost. Immune sera displayed neutralizing activity in three assays against pseudoviruses and primary isolates from subtypes A, AG, B, C, and D. Polyclonal Abs in the immune rabbit sera neutralized viruses that were not neutralized by pools of human anti-V3 monoclonal Abs. Greater than 80% of the neutralizing Abs were specific for V3, showing that the immune response could be focused on a neutralizing epitope and that vaccine-induced anti-V3 Abs have cross-clade neutralizing activity.     

Highly conserved HIV-1 gp120 glycans proximal to CD4-binding region affect viral infectivity and neutralizing antibody induction

Glycosylation plays important roles in gp120 structure and HIV-1 immune evasion. In the current study, we introduced deglycosylations into the 24 N-linked glycosylation sites of a R5 env MWS2 cloned from semen and systematically analyzed the impact on infectivity, antigenicity, immunogenicity and sensitivity to entry inhibitors. We found that mutants N156-T158A, N197-S199A, N262-S264A and N410-T412A conferred decreased infectivity and enhanced sensitivity to a series of antibodies and entry inhibitors. When mice were immunized with the DNA of wild-type or mutated gp160, gp140 or gp120; N156-T158A, N262-S264A and N410-T412A were more effective in inducing neutralizing activity against wild-type MWS2 as well as heterologous IIIB and CH811 Envs. In general, gp160 and gp140 induced higher neutralizing activity compared with gp120. Our study demonstrates for the first time that removal of individual glycan N156, N262 or N410 proximal to CD4-binding region impairs viral infectivity and results in enhanced capability to induce neutralizing activity.     

Safety,pharmacokinetics and neutralization of the broadly neutralizing HIV-1 human monoclonal antibody VRC01 in healthy adults

VRC-HIVMAB060-00-AB (VRC01) is a broadly neutralizing HIV-1 monoclonal antibody (mAb) isolated from the B cells of an HIV-infected patient. It is directed against the HIV-1 CD4 binding site and is capable of potently neutralizing the majority of diverse HIV-1 strains. This Phase I dose-escalation study in healthy adults was conducted at the National Institutes of Health (NIH) Clinical Center (Bethesda, MD, USA). Primary objectives were the safety, tolerability and pharmacokinetics (PK) of VRC01 intravenous (i.v.) infusion at 5, 20 or 40 mg/kg, given either once (20 mg/kg) or twice 28 days apart (all doses), and of subcutaneous (s.c.) delivery at 5 mg/kg compared to s.c. placebo given twice, 28 days apart. Cumulatively, 28 subjects received 43 VRC01 and nine received placebo administrations. There were no serious adverse events or dose-limiting toxicities. Mean 28-day serum trough concentrations after the first infusion were 35 and 57 μg/ml for groups infused with 20 mg/kg (n = 8) and 40 mg/kg (n = 5) doses, respectively. Mean 28-day trough concentrations after the second infusion were 56 and 89 μg/ml for the same two doses. Over the 5–40 mg/kg i.v. dose range (n = 18), the clearance was 0·016 l/h and terminal half-life was 15 days. After infusion VRC01 retained expected neutralizing activity in serum, and anti-VRC01 antibody responses were not detected. The human monoclonal antibody (mAb) VRC01 was well tolerated when delivered i.v. or s.c. The mAb demonstrated expected half-life and pharmacokinetics for a human immunoglobulin G. The safety and PK results support and inform VRC01 dosing schedules for planning HIV-1 prevention efficacy studies.