Binding of HIV-1 virions to α_4β_7 expressing cells and impact of antagonizing α_4β_7 on HIV-1 infection of primary CD4^+ T cells

HIV-1 envelope glycoprotein is reported to interact with α4β7, an integrin mediating the homing of lymphocytes to gut-associated lymphoid tissue, but the significance of α4β7 in HIV-1 infection remains controversial. Here, using HIV-1 strain Ba L, the gp120 of which was previously shown to be capable of interacting with α4β7, we demonstrated that α4β7 can mediate the binding of whole HIV-1 virions to α4β7-expressing transfectants. We further constructed a cell line stably expressing α4β7 and confirmed the α4β7-mediated HIV-1 binding. In primary lymphocytes with activated α4β7 expression, we also observed significant virus binding which can be inhibited by an anti-α4β7 antibody. Moreover, we investigated the impact of antagonizing α4β7 on HIV-1 infection of primary CD4+ T cells. In α4β7-activated CD4+ T cells, both anti-α4β7 antibodies and introduction of shorthairpin RNAs specifically targeting α4β7 resulted in a decreased HIV-1 infection. Our findings indicate that α4β7 may serve as an attachment factor at least for some HIV-1 strains. The established approach provides a promising means for the investigation of other viral strains to understand the potential roles of α4β7 in HIV-1 infection.

Trizivir (Abacavir/Lamivudine/Zidovudine) plus Lopinavir/Ritonavir Induction Therapy Followed by Trizivir-Alone Maintenance for HIV-1-Infected Patients: A 96-Week Pilot Treatment Simplification Study

Objective: The purpose of this study was to investigate whether switching HIV-infected patients stabilized on Trizivir (abacavir 300 mg/lamivudine 150 mg/zidovudine 300 mg) plus lopinavir/ritonavir 400 mg/100mg twice daily to Trizivir alone affects clinical efficacy and tolerability. Methods: This phase 4, open-label, pilot study was conducted over 96 weeks in 23 antiretroviral-na?ve, HIV-infected patients. Initially, these patients received induction therapy with Trizivir plus lopinavir/ritonavir 400 mg/100mg twice daily. Patients who achieved a viral load 3. Nineteen patients completed induction;of the four who did not, three were lost to follow-up and one withdrew due to gastrointestinal adverse events. In 14 induction completers who had viral load measurements taken at week 48, intent-to-treat: observed analysis showed a week 48 viral load 3 higher than the baseline count. Twelve patients completed the subsequent 48-week Trizivir-alone maintenance phase, of whom 11 (92%) achieved viral loads of both 3 above baseline. Trizivir-only maintenance was associated with fewer adverse events than the Trizivir-lopinavir/ritonavir induction phase and with improvement in total cholesterol, LDL-cholesterol, and triglycerides. Conclusions: Trizivir-alone maintenance after Trizivir-lopinavir/ritonavir induction maintained virologic and CD4+ cell response, and was associated with an improved adverse event and lipid profile.

Cloning and analysis of the envelope protein clone of HIV-1, CHNHLJ03009c34 from an infected individual in Heilongjiang province

To analyze the variability and phenotype of envelope glycoprotein （Env） of human immunodeficiency virus type 1 （HIV-1） prevalent in Heilongjiang province, cloning of the full-length env gene from the peripheral blood mononuclear cells （PBMCs） of an HIV-1 positive individual in Heilongjiang province in China was performed by using conserved region primers. The amplified PCR products were cloned into a plasmid vector and sequenced. Phylogenetic analysis was done upon the full-length Env amino acid sequence. Subsequently, an HIV-1 pseudotyped virus bearing the envelope protein was constructed and the infectivity was examined using U87 cell lines expressing CD4 with either CCR5 or CXCR4. As the result, two functional env clones named as CHNHLJ03009c34 （GenBank Accession No： AY905493 ） and CHNHLJ03009c33 were obtained. It was found that the homology between CHNHLJ03009c34 and an HIV-1 subtype B＇ strain, RIA-2, isolated from Yunnan province, was 91.52% through comparing and analyzing full-length Env amino acid sequence of HIV-1 isolated from either China or abroad. Phylogenetic analysis indicated that CHNHLJ03009c34 has the closest molecular relation with strain RIA2 based on analyzing the full-length of the Env, while it became an independent branch upon analyzing the sequences of C2-V3 region of the Env. The secondary structure analysis of the envelope protein showed that the antigenicity and hydrophobicity of the strain demonstrated have no definite difference from that of RL42. Examination of infectivity showed that pseudovirus CHNHLI03009c34 could only infect U87. CD4. CCR5 cells, indicating that it was a RS-tropic HIV-1. In the conclusion, two HIV-1 env clones from an infected individual in Heilongjiang province have been identified as subtype B＇ and RS-tropic HIV-1. This is the first report on the analysis of primary isolates in Heilongjiang province.

2008-2009年北京市男男性行为者HIV-1感染率与新发感染率调查

目的了解北京市男男性行为者（MSM）人群HIV-1感染率与新发感染率情况。方法对北京市2008—2009年三轮MSM人群进行横断面调查，采用酶联免疫吸附试验（ELISA）与蛋白印迹实验（WB）对监测样本进行初筛与确证实验。再对血清学确认为HIV-1阳性的样本进行BEDHⅢ捕获酶联法（BED方法）检测。结果在1833份监测样本中共筛出96份HIV-1阳性样本，其中进行BED方法检测的样本数为68例，判定为新近感染的样本为36例。三轮MSM人群HIV感染率分别为5．9％、5．0％、4．9％；三轮MSM人群新发感染率分别为4．83％（2．36％～7．54％）、4．83％（2．36％～7．54％）、2．65％（0．82％～4．55％）。结论北京市2008～2009年度MSM人群HIV的感染率与新发感染率均达到较高水平。

Viral infections and cell cycle G2/M regulation

Progression of cells from G2 phase of the cell cycle to mitosis is a tightly regulated cellular process that requires activation of the Cdc2 kinase, which determines onset of mitosis in all eukaryotic cells. In both human and fission yeast (Schizosaccharomyces pombe) cells, the activity of Cdc2 is regulated in part by the phosphorylation status of tyrosine 15 (Tyr15) on Cdc2, which is phosphorylated by Wee1 kinase during late G2 and is rapidly dephosphorylated by the Cdc25 tyrosine phosphatase to trigger entry into mitosis. These Cdc2 regulators are the downstream targets of two well- characterized G2/M checkpoint pathways which prevent cells from entering mitosis when cellular DNA is damaged or when DNA replication is inhibited. Increasing evidence suggests that Cdc2 is also commonly targeted by viral proteins, which modulate host cell cycle machinery to benefit viral survival or replication. In this review, we describe the effect of viral protein R (Vpr) encoded by human immunodeficiency virus type 1 (HIV-1) on cell cycle G2/M regulation. Based on our current knowledge about this viral effect, we hypothesize that Vpr induces cell cycle G2 arrest through a mechanism that is to some extent different from the classic G2/M checkpoints. One the unique features distinguishing Vpr-induced G2 arrest from the classic checkpoints is the role of phosphatase 2A (PP2A) in Vpr-induced G2 arrest. Interestingly, PP2A is targeted by a number of other viral proteins including SV40 small T antigen, polyomavirus T antigen, HTLV Tax and adenovirus E4orf4. Thus an in-depth understanding of the molecular mechanisms underlying Vpr-induced G2 arrest will provide additional insights into the basic biology of cell cycle G2/M regulation and into the biological significance of this effect during host-pathogen interactions.

Laboratory Profile of HIV-2 and Dual HIV-1/HIV-2 Associated Acquired Immunodeficiency Syndrome in Nigeria

Background: HIV-2 is comparatively less pathogenic with slow progression of infection to clinical disease and consequently there is less of information on the occurrence of HIV-2 associated disease than HIV-1. We hereby describe some laboratory profiles of individuals presenting with HIV-2 and dual HIV-1/2 related AIDS at the University College hospital in Ibadan over a period of seven years. Methodology: Blood samples from patients presenting with the AIDS defining illness at the University College Hospital, Ibadan, Nigeria were tested for antibodies to HIV-1/2 using rapid test devices or ELISA. Initially reactive samples were further tested by immunoblotting for differentiation into HIV-1 or HIV-2 or HIV-1/2 dual infection. Blood samples from individuals with confirmed infections were further analyzed for CD4 cell lymphocyte number, plasma HIV-1 RNA concentration, hematological and blood chemistry parameters. The data analysis was done using descriptive statistics and Levene-S test for equality of variance. Results: Thirty five patients, 18 and 17 with HIV-2 and dual HIV-1/2 infections respectively were identified during the period covered by this study (2005-2012). The median age of the patients was 48 years old (Range: 42 - 70 years old) and mean CD4 cell count of HIV-2 patients at enrollment was 324 (Range: 16 - 696) and 350 (Range 54 - 863) per microlitre of blood for patients with dual HIV-1/2 infection. HIV-1 RNA was not detected in the plasma of the 18 patients with serological HIV-2 infection but 2 (11.8%) of the 17 patients with dual HIV-1/2 serological profile had detectable HIV-1 RNA (1,287,275 copies/ml and 1,816,491 copies/ml). Conclusion: The results emphasize the need to consider HIV-2 infection in the investigation of patients presenting with the AIDS related illness but with negative HIV-1serology. The study also shows the importance of inclusion of multispot HIV-1 and 2 rapid tests for differentiating HIV-1 from HIV-2 infections in regions where both types of HIV circulate or epidemiologically indicated.

Prokaryotic Expression and Purification of HIV-1 Vif and hAPOBEC3G, Preparation of Polyclonal Antibodies

To prepare HIV-1 Vif and hAPOBEC3G and to produce their antibodies, the full length gene fragment of HIV-1 vif was amplified by PCR from a plasmid of HIV-1 NL4.3 cDNA, and the APOBEC3G gene was obtained by RT-PCR from the total RNA of H9 cells. The resulting DNA construct was cloned into a prokaryotic expression vector (pET-32a). Recombinant pET-vif and pET-APOBEC3G were expressed respectively in Eserichia coli BL21 (DE3) as an insoluble protein. The vector also contained a six-histidine tag at the C-terminus for convenient purification and detection. To express and purify the HIV-1 Vif and hAPOBEC3G in E.coli cells, the accuracy of inserted gene and specificity of proteins were detected by the two enzyme digestion method, SDS-PAGE, and Western blotting. Rabbits were then immunized by Vif or APOBEC3G protein and serum samples were tested by indirect ELISA to determine the level of antibodies. Immunoenzyme and immunofluorescence assays were performed to identify the specificity of polyclonal antibodies. The titer of the anti-Vif antibodies was 1:204800, and that of the anti-APOBEC3G antibodies was 1:102400. Thus the antibodies could detect the antigen expression in the cells, demonstrating that fusion proteins with high purity and their corresponding polyclonal antibodies with high titer and specificity were achieved.

HIV-1 Primarily Targets the Innate Immune System and Only Secondarily Modulates Adaptive Immune Cell Depletion

Persistence of HIV-1 infection allows for permissive microenvironmental conditioning in terms of contextual innate immune participation. The progression of host cell injury constitutes an additional parametric formulation in self-amplifying modulation of the adaptive immune response in a manner that inclusively promotes the emergence of a final stage of AIDS that is both depletive and permissive for opportunistic infections and various forms of neoplasia. It is within contextual indices of promotion of depleted T-helper lymphocytes and of augmented viremic loads that manifestations of classic lesions emerge as the AIDS phenomenon. It is further to be realized that an apoptotic response of multiple cell subtypes including T-lymphocytes includes host-cell participation within formulated settings of further persistence of the retroviral infection. An all-inclusive phenomenon of dendritic cell-lymphocyte synapse formulation corresponds to the establishment of HIV-1 infection that specifically conditions all subsequent stages in depletion of the injured host cells regardless of the dynamics or kinetics of the retroviral replicative infectious process itself.

Nonlinear Uncertain HIV-1 Model Controller by Using Control Lyapunov Function

In this paper, we introduce a new Control Lyapunov Function (CLF) approach for controlling the behavior of nonlinear uncertain HIV-1 models. The uncertainty is in decay parameters and also external control setting. CLF is then applied to different strategies. One such strategy considers input into infected cells population stage and the other considers input into a virus population stage. Furthermore, by adding noise to the HIV-1 model a realistic comparison between control strategies is presented to evaluate the system’s dynamics. It has been demonstrated that nonlinear control has effectiveness and robustness, in reducing virus loading to an undetectable level.

Stochastic HIV Infection Model with CTLs Immune Response Driven by Lévy Jumps

This paper mainly investigates the effect of the lévy jumps on the stochastic HIV infection model with cytotoxic T lymphocytes (CTLs) immune response. First, we prove that there is a unique global positive solution in any population dynamics, then we find sufficient conditions for the extinction of the disease. For proofing the persistence in mean, a special Lyapunov function be established, we obtain that if the infected CD4+ T-cells and virus particles will persistence in mean. Finally, numerical simulations are carried out to illustrate the theoretical results.

Detection of recent HIV-1 infections among men who have sex with men in Beijing during 2005-2006

Background Men who have sex with men （MSM） have become one of the most risky populations for HIV infection in China. Though several cross-sectional sero-prevalence studies have been conducted, the annual HIV incidence remains unknown in this population.Methods We applied IgG-capture BED-enzyme immunoassay （BED-CEIA） to define the recent HIV-1 infections among MSM in Beijing in the years 2005 and 2006 and the annual HIV incidence was estimated.Results Overall, 1067 MSM samples were collected, including 526 samples in the year 2005 and 541 in 2006. In 2005, of 17 HIV seropositive samples, 7 were identified as recent HIV-1 infections and the estimated HIV infection incidence was 2.9% per year （95% CI, 0.8%-5.0%）. In 2006, of 26 HIV seropositive samples, 9 were identified as recent HIV-1 infections and the estimated annual incidence was 3.6% （95% CI, 1.3%-5.9%）, which was 0.7% higher than that in 2005. Individuals engaging in male group sexual intercourse （5.17% vs 0.87%, P=0.019） and having receptive anal sexual intercourse more than five times （2.79% vs 0.33%, P=0.047） in the past 6 months significantly increase the risk of being infected by HIV-1.Conclusions A high level of annual HIV-1 infection incidence was observed among MSM in Beijing for the consecutive years 2005 and 2006 with a continuous increasing trend. The rising incidence and related high risk behavior among MSM alarmed the health authorities and calls for more effective intervention strategies among this population.

DYNAMICS OF AN HIV-1 INFECTION MODEL WITH CELL-MEDIATED IMMUNE RESPONSE AND STOCHASTIC PERTURBATION

In this paper, we introduce the stochasticity into an HIV-1 infection model with cytotoxic T lymphocytes （CTLs） immune response via the technique of parameter perturbation. We show that there is a positive solution as desired in any population dynamics. Then we analyze the long time behavior of this model. We obtain a sufficient condition for the stochastic asymptotic stability in the large of the infection-free equilibrium and give the conditions for the solution fluctuating around the two infection equilibria （one without CTLs being activated and the other with）. Finally, we make sinmlations to conform to our analytical results.

GLOBAL DYNAMICS OF A DELAYED HIV-1 INFECTION MODEL WITH ABSORPTION AND SATURATION INFECTION

In this paper, an HIV-1 infection model with absorption, saturation infection and an intracellular delay accounting for the time between viral entry into a target cell and the production of new virus particles is investigated. By analyzing the characteristic equations, the local stability of an infection-free equilibrium and a chronic-infection equilibrium of the model is established. By using suitable Lyapunov functionals and LaSalle＇s invariance principle, it is proved that if the basic reproduction ratio is less than unity, the infection-free equilibrium is globally asymptotically stable; and if the basic reproduction ratio is greater than unity, sufficient condition is derived for the global stability of the chronic-infection equilibrium.

DYNAMICS OF A NON-AUTONOMOUS HIV-1 INFECTION MODEL WITH DELAYS

In this paper, following a previous paper （[32] Permanence and extinction of a non- autonomous HIV-I model with two time delays, preprint） on the permanence and extinc- tion of a delayed non-autonomous HIV-1 within-host model, we introduce and investigate a delayed HIV-1 model including maximum homeostatic proliferation rate of CD4＋ T- cells and varying coefficients. By applying the asymptotic analysis theory and oscillation theory, we show： （i） the system will be permanent when the threshold value R. 〉 1, and for this case we also obtain the explicit estimate of the eventual lower bound of the HIV-1 virus load; （ii） the threshold value R＊ 〈 1 implies the extinction of the virus. Furthermore, we obtain that the threshold dynamics is in agreement with that of the corresponding autonomous system, which extends the classic results for the system with constant coefficients. Numerical simulations are also given to illustrate our main results, and in particular, some sensitivity test of R. is established.

The Establishment of an In Vivo HIV-1 Infection Model in Humanized B-NSG Mice

Suitable animal models for human immunodeficiency virus type 1(HIV-1)infection are important for elucidating viral pathogenesis and evaluating antiviral strategies in vivo.The B-NSG(NOD-PrkdcscidIl2rgtm1/Bcge)mice that have severe immune defect phenotype are examined for the suitability of such a model in this study.Human peripheral blood mononuclear cells(PBMCs)were engrafted into B-NSG mice via mouse tail vein injection,and the repopulated human T-lymphocytes were observed at as early as 3-weeks post-transplantation in mouse peripheral blood and several tissues.The humanized mice could be infected by HIV-1,and the infection recapitulated features of T-lymphocyte dynamic observed in HIV-1 infected humans,meanwhile the administration of combination antiretroviral therapy(cART)suppressed viral replication and restored T lymphocyte abnormalities.The establishment of HIV-1 infected humanized B-NSG mice not only provides a model to study virus and T cell interplays,but also can be a useful tool to evaluate antiviral strategies.

Frequency of HLA-A*03 associates with HIV-1 infection in a Chinese cohort

During the early mid-1990s, a number of rural farmers across central China were employed to the unregulated plasma- selling-activity and many of them were infected by HIV-1. However, AIDS progression in the former blood donors （FBDs） is various. The aim of this study is to assess human leukocyte antigen （HLA） class I allele distribution in FBDs and evaluate its association with HIV-1 infection and disease progression. A total of 353 FBDs were enrolled in the cohort including 294 ART na＇fve HIV-1 seropositive and 59 HIV-1 seronegative age-matched subjects. The viral load and CD4/CD8 T cell counts were assessed in all subjects. Compared with HIV-seropositive group, the frequency of HLA-A＊03 in control was significantly higher. After classifying the HLA-B alleles of the subjects according to the presence of Bw4/Bw6 serological epitopes, detri- mental effect of HLA Bw6/Bw6 homozygosity was also confirmed in the HIV-seropositive subjects. This study provides nov- el evidence on HLA class I allele distribution and association of HLA-A＊03 frequency with HIV-1 infection and viremia in the HIV-1 infected FBDs, which may throw light on intervention strategy for the HIV-1 infection and our understanding how host immunity and genetic background affect HIV infection and AIDS progression.

Investigating the effect of pyroptosis on the slow CD4+T cell depletion in HIV-1 infection,by dynamical analysis of its discontinuous mathematical model

HIV infection is one of the most serious causes of death throughout the world.CD4+T cells which play an important role in immune protection,are the primary targets for HIV infection.The hallmark of HIV infection is the progressive loss in population of CD4+T cells.However,the pathway causing this slow T cell decline is poorly understood[16].This paper studies a discontinuous mathematical model for HIV-1 infection,to investigate the effect of pyroptosis on the disease.For this purpose,we use the theory of discontinuous dynamical systems.In this way,we can better analyze the dynamical behavior of the HIV-1 system.Especially,considering the dynamics of the system on its discontinuity boundary enables us to obtain more comprehensive results rather than the previous researches.A stability region for the system,corresponding to its equilibria on the discontinuity boundary,will be determined.In such a parametric region,the trajectories of the system will be trapped on the discontinuity manifold forever.It is also shown that in the obtained stability region,the disease can lead to a steady state in which the population of uninfected T cells and viruses will preserve at a constant level of cytokines.This means that the pyroptosis will be restricted and the disease cannot progress for a long time.Some numerical simulations based on clinical and experimental data are given which are in good agreement with our theoretical results.

Combination of Tripterygium Wilfordii Hook F With Antiretroviral Therapy Delayed Viral Rebound in A Patient of Acute HIV-1 Infection

Prolonged antiretroviral therapy(ART)-free remission post-treatment has been observed and reported in human immunodeficiency virus-1(HIV-1)infection.The primary factors for such achievement have been linked to the transcriptional inactivation of HIV-1 DNA and immune recovery.Here,we reported a patient with acute HIV-1 infection who immediately received intensified quadruple ART.At month 9(M9),an old CFDA-approved immuno-suppressive herbal medicine,Tripterygium Wilfordii Hook F(TwHF),was used in addition to ART.The patient was closely monitored.Virological and immunological tests as well as transcriptome analysis were carried out at each visit.The results showed that TwHF reduced serum IP-10 level and inhibited T cell activation.Both ART and TwHF were discontinued in M24,and levels of peripheral blood HIV-1 RNA and DNA remained suppressed for consecutive 12months.With transcriptome analysis,we found pattern changes linking immuno-activation and amino acid metabolism with viral suppression and rebound.This indicates that the intentional suppression of immuno-activation is a promising approach for a functional cure of HIV-1 infection.

重庆市2006-2008年男男性行为人群HIV-1感染发病率调查

目的用连续横断面调查和BED-捕获酶联试验（BED-CEIA）估算重庆市男男性行为（MSM）人群中HIV-1的发病率及其变化趋势。方法利用“滚雪球”和“方便抽样”方法招募得到样本，用BED-CEIA进行HIV-1新近感染检测，并根据标准公式和2种校正公式估算该人群2006--2008年连续3年的发病率；比较不同抽样场所和不同年龄组所得结果，进行发病率的分层分析。结果2006—2008年调查人数分别为1000、1044和945，HIV-1年感染发病率分别为7．01％、7．98％和7．80％。不同采样场所的HIV-1感染发病率差异有统计学意义，2007年和2008年MSM发病率最高的人群分别来自浴室和通过网络寻找性伴的MSM，分别达到17．87％和12．22％；2008年21～25岁年龄组HIV-1发病率最高，达8．69％；不同方法的校正降低了对发病率的估计。结论重庆市MSM人群HIV-1新发感染维持在较高水平，但连续3年的发病率经校正后上升趋势不明显。