Cross-reactive monoclonal antibodies to multiple HIV-1 subtype and SIVcpz envelope glycoproteins

The extraordinarily high level of genetic variation of HIV-1 env genes poses a challenge to obtain antibodies that cross-react with multiple subtype Env glycoproteins. To determine if cross-reactive monoclonal antibodies (mAbs) to highly conserved epitopes in HIV-1 envelope glycoproteins can be induced, we immunized mice with wild-type or consensus HIV-1 Env proteins and characterized a panel of ten mAbs that reacted with varying breadth to subtypes A, B, C, D, F, G, CRF01_AE, and a highly divergent SIVcpzUS Env proteins by ELISA and Western blot analysis. Two mAbs (3B3 and 16H3) cross-reacted with all tested Env proteins, including SIVcpzUS Env. Surface plasmon resonance analyses showed both 3B3 and 16H3 bound Env proteins with high affinity. However, neither neutralized primary HIV-1 pseudoviruses. These data indicate that broadly reactive non-neutralizing monoclonal antibodies can be elicited, but that the conserved epitopes that they recognize are not present on functional virion trimers. Nonetheless, such mAbs represent valuable reagents to study the biochemistry and structural biology of Env protein oligomers.     

缺血性脑卒中TOAST分型及其复发率和危险因素分析

目的探讨缺血性脑卒中患者类肝素药物治疗急性缺血性脑卒中试验（TOAST）病因分型各亚型的构成、危险因素及与复发的关系。方法采用前瞻性队列研究方法,对2006年10月1日至2007年9月30日本院首发急性缺血性脑卒中患者441例的临床资料,按照TOAST标准进行病因分型,随访1年,记录终点事件。结果TOAST分型各亚型构成为不明病因型（SUE）42．3％、小动脉闭塞型（SAO）30．9％、大动脉粥样硬化型（LAA）17．3％、心源性栓塞型（CE）9．3％、其他明确病因型（SOE）0．2％;各亚型分布在性别、年龄上差异有统计学意义;缺血性脑卒中各亚型1年复发率分别为CE33．3％、SUE14．6％、LAA 13．7％、SAO6．9％;各亚型在吸烟史、高血压、糖尿病、心脏病、总胆固醇、低密度脂蛋白、纤维蛋白原、血糖等方面差异有统计学意义。结论TOAST分型各亚型间的复发率及危险因素不尽相同,可以为缺血性脑卒中二级预防提供参考依据。     

河南省人免疫缺陷病毒1型流行现状研究

目的 了解河南省人免疫缺陷病毒1型(HIV-1)毒株的亚型状况及序列变异、流行特征,分析其传播来源和传播规律.方法 对2006-2007年在河南省采集的1287例HIV-1感染者抽取静脉血,用巢式聚合酶链反应(nest-PCR)对单个核细胞中前病毒脱氧核糖核酸的env基因和gag基因进行扩增,并测定和分析核苷酸序列.结果 1287份样本中存在B'、C亚型及BC、AE两个重组亚型,其在所有分析样本中的比例分别为95.882%(1234/1287)、0.466%(6/1287)、2.875%(37/1287)、0.777%(10/1287).与国内及国际的参考毒株RL42、C.95in21068、07-BC.CN.97.C54A、01AE.TH.90.CM240间的离散率分别为(9.327±0.245)%、(5.214±0.183)%、(6.278±0.194)%、(5.332±0.1 58)%.结论 目前河南省艾滋病感染者中有B'、C亚型及BC、AE两个重组亚型.泰国B'亚型依然占主导地位.B'亚型以既往有偿献血人员为主,BC亚型以性传播为主,AE亚型以性传播及既往献血途径为主,C亚型以性传播为主.     

HIV-1 Tat-specific IgG antibodies in high-responders target a B-cell epitope in the cysteine-rich domain and block extracellular Tat efficiently

Tat, an important regulatory protein of HIV-1, has been implicated in HIV-related pathogenesis. Immune responses to Tat, although underrepresented, confer protection against disease progression, in natural infection and experimental immunization, making Tat an attractive vaccine candidate. Information on immune responses to Tat from India which has the second largest HIV incidence has been lacking. Here we report a cross-sectional study evaluating the humoral response to Tat from a large number of samples from two southern states of India. 14% of the seropositive (63/447) and 4.6% of seronegative samples (7/150) harbored Tat-reactive antibodies. A significant number of the seropositive samples contained high levels of anti-Tat antibodies (31/447) which demonstrated class-switch to IgG1 and bound to Tat with high avidity. Cross-reactivity analysis showed that these antibodies interacted with Tat from different clades with variable degree withthe highest interaction with subtype-AE and the least with subtype-B Tat. Importantly, a B-cell epitope in the cysteine-rich domain was found to be the most immunodominant one and antibodies interacting with this epitope blocked extracellular Tat efficiently. To the best of our knowledge this is the first report on immune responses to Tat from Indian populations and the data presented here could significantly contribute to HIV Tat vaccine design.     

GABA(A) receptor subtype-selective efficacy: TPA023, an alpha2/alpha3 selective non-sedating anxiolytic and alpha5IA, an alpha5 selective cognition enhancer

TPA023 and α5IA are structurally related compounds that selectively modulate certain GABA_A receptor subtypes. Hence, TPA023 has weak partial agonist efficacy at the α2 and α3 subtypes whereas α5IA has inverse agonist efficacy at the α5 subtype. These efficacy characteristics translate into novel pharmacological profiles in preclinical species with TPA023 being a nonsedating anxiolytic in rats and primates whereas α5IA enhanced cognition in rats but was devoid of the proconvulsant or kindling liabilities associated with nonselective inverse agonists. In vitro and in vivo metabolic studies showed that TPA023 was metabolized via CYP3A4-mediated t -butyl hydroxylation and N -deethylation whereas α5IA was metabolized to produce the hydroxymethyl isoxazole, the latter of which was highly insoluble and caused renal toxicity in preclinical species. In humans, TPA023 had a half-life in the region of 6–7 h whereas the half-life of α5IA was 2–2.5 h. TPA023 was clearly differentiated from the nonselective agonist lorazepam in terms of saccadic eye movement and unlike lorazepam, it did not impair either postural stability, as judged by body sway, or cognition. The occurrence of the hydroxymethyl isoxazole metabolite of α5IA in human urine precluded the use of α5IA in prolonged dosing studies. Nevertheless, α5IA was evaluated in an alcohol-induced cognitive impairment model in healthy normal volunteers and was found to reverse the memory-impairing effects of alcohol. To date, however, no efficacy data for either TPA023 or α5IA in patient populations has been reported, although at the very least, the preclinical and limited clinical data with TPA023 and α5IA validate the approach of targeting specific GABA_A receptors through subtype-selective efficacy.     

HIV-1与HIV-2交叉反应毒株的基因亚型分析

目的分析HIV-1+2蛋白印迹试验中HIV-1确证阳性同时出现HIV-2带型样本的基因亚型。方法将HIV-1+2确证试验中同时出现HIV-2带型的样本,通过基因诊断确认是否为HIV-2共感染;同时扩增HIV-1 gag,env基因段,通过测序和系统进化树的构建,分析具有HIV-2带型的HIV-1毒株的基因亚型。结果在34份出现HIV-2带型的标本中,基因诊断发现均为交叉反应,并非HIV-1和HIV-2共感染。出现交叉反应的毒株中以AE亚型为主,占73.5%(25/34),BC重组和B亚型分别占17.7%(6/34)和8.8%(3/34)。结论HIV-1+2蛋白确证试验中HIV-1确证阳性,同时出现HIV-2带型的阳性样本,并非HIV-1和HIV-2共感染,而是交叉反应。出现交叉反应的HIV-1毒株以AE亚型为主。     

Adaptive changes in HIV-1 subtype C proteins during early infection are driven by changes in HLA-associated immune pressure

It is unresolved whether recently transmitted human immunodeficiency viruses (HIV) have genetic features that specifically favour their transmissibility. To identify potential “transmission signatures”, we compared 20 full-length HIV-1 subtype C genomes from primary infections, with 66 sampled from ethnically and geographically matched individuals with chronic infections. Controlling for recombination and phylogenetic relatedness, we identified 39 sites at which amino acid frequency spectra differed significantly between groups. These sites were predominantly located within Env, Pol and Gag (14/39, 9/39 and 6/39 respectively) and were significantly clustered (33/39) within known immunoreactive peptides. Within 6 months of infection, we detected reversion-to-consensus mutations at 14 sites and potential CTL escape mutations at seven. Here we provide evidence that frequent reversion mutations probably allows the virus to recover replicative fitness which, together with immune escape driven by the HLA alleles of the new hosts, differentiate sequences from chronic infections from those sampled shortly after transmission.     

神经性厌食患者血小板 5-羟色胺浓度的对照研究

目的研究5-羟色胺（5-HT）在神经性厌食发病中的作用。方法采用高效液相色谱法,分别测定37例神经性厌食患者和34例正常对照者的血小板5-HT含量。结果神经性厌食患者血小板5-HT水平[（2.2±1.4）nmol/109个血小板]低于正常对照组[（4.4±0.9）nmol/109个血小板],差异有统计学意义（t=-7.845;P〈0.01）;两亚型即约束型[（2.4±1.1）nmol/109个血小板]与暴食/清除型[（2.0±1.6）nmol/109个血小板]神经性厌食患者血小板5-HT浓度比较,差异无统计学意义（P〉0.05）。结论本研究结果支持神经性厌食患者5-HT能低下的假说;并提示约束型与暴食/清除型神经性厌食发病有着相同的5-HT机制。     

Antigenicity and immunogenicity of HIV-1 consensus subtype B envelope glycoproteins

"Centralized" (ancestral and consensus) HIV-1 envelope immunogens induce broadly cross-reactive T cell responses in laboratory animals; however, their potential to elicit cross-reactive neutralizing antibodies has not been fully explored. Here, we report the construction of a panel of consensus subtype B (ConB) envelopes and compare their biologic, antigenic, and immunogenic properties to those of two wild-type Env controls from individuals with early and acute HIV-1 infection. Glycoprotein expressed from full-length (gp160), uncleaved (gp160-UNC), truncated (gp145), and N-linked glycosylation site deleted (gp160-201N/S) versions of the ConB env gene were packaged into virions and, except for the fusion defective gp160-UNC, mediated infection via the CCR5 co-receptor. Pseudovirions containing ConB Envs were sensitive to neutralization by patient plasma and monoclonal antibodies, indicating the preservation of neutralizing epitopes found in contemporary subtype B viruses. When used as DNA vaccines in guinea pigs, ConB and wild-type env immunogens induced appreciable binding, but overall only low level neutralizing antibodies. However, all four ConB immunogens were significantly more potent than one wild-type vaccine at eliciting neutralizing antibodies against a panel of tier 1 and tier 2 viruses, and ConB gp145 and gp160 were significantly more potent than both wild-type vaccines at inducing neutralizing antibodies against tier 1 viruses. Thus, consensus subtype B env immunogens appear to be at least as good as, and in some instances better than, wild-type B env immunogens at inducing a neutralizing antibody response, and are amenable to further improvement by specific gene modifications.