Genotypic characterization of HIV type 1 env gp160 sequences from three regions in Thailand

Molecular Epidemiology of Human Immunodeficiency Virus

During the evolution of human immunodeficiency virus (HIV), transmissions between humans and primates resulted in multiple HIV lineages in humans. This evolution has been rapid, giving rise to a complex classification and allowing for worldwide spread and intermixing of subtypes, which has consequently led to dozens of circulating recombinant forms. In the Republic of Korea, 12,522 cases of HIV infection have been reported between 1985, when AIDS was first identified, and 2015. This review focuses on the evolution of HIV infection worldwide and the molecular epidemiologic characteristics of HIV in Korea.

Analyzing the interaction of a herbal compound Andrographolide from Andrographis paniculata as a folklore against swine flu (H1N1)

Objective

To find new bioactive molecules for the treatment of swine flu.

Methods

The present study is an attempt to elucidate inhibition potential of andrographolide and its derivatives along with an associated binding mechanism through virtual screening and molecular docking simulation studies.

Results

Our findings revealed structural conformation changes in 150 loop, secondary sialic acid binding site residues of ACZ97474 {Neuraminidase (A/Blore/NIV236/2009(H1N1)}. Andrographolide have been identified as the highest binging energy of -10.88 Kcal/mol, 3 hydrogen bond interactions (Arg152, Lys150, and Gly197), total intermolecular energy of -12.07 Kcal/mol with bioactivity value (Ki) of 10.59 nmol/L, while the Food and Drug Admistraton approved drug Oseltamivir and Zanamivir have shown 2 and 4 hydrogen bond interactions with binding energies of -6.28 Kcal/mol and -7.73Kcal/mol, respectively, which is higher than andrographolide. The guanidine group of Arg152 has binding affinities to the hydrophilic nature of the inhibitors (-OH and =O groups), as identified by docking of andrographolide (CID: 5318517) on neuraminidase.

Conclusions

Hence, andrographolide has the potential to inhibit neuraminidase activity of H1N1 and may be used as an alternative medicinal therapy for swine flu positive patient. With potent antiviral activity and a potentially new mechanism of action, andrographolide may warrant further evaluation as a possible therapy for influenza.

HIV-1 tropism testing and clinical management of CCR5 antagonists: Quebec review and recommendations

HIV-1 tropism assays play a crucial role in determining the response to CCR5 receptor antagonists. Initially, phenotypic tests were used, but limited access to these tests prompted the development of alternative strategies. Recently, genotyping tropism has been validated using a Canadian technology in clinical trials investigating the use of maraviroc in both experienced and treatment-naive patients. The present guidelines review the evidence supporting the use of genotypic assays and provide recommendations regarding tropism testing in daily clinical management.

CRF01_AE subtype is associated with X4 tropism and fast HIV progression in Chinese patients infected through sexual transmission

BACKGROUND

The molecular epidemiology of the HIV-1 CRF01_AE subtype as a risk factor for fast HIV-1 progression remains poorly understood.

METHODS

We analyzed HIV-1 tropism by utilizing samples from 201 treatment-naive patients in our multicenter cohort (12 research centers in different provinces of China). Tropism was determined by V3 loop sequencing. Data from 235 treatment-naive patients infected sexually (including aforementioned 201 patients) in this cohort with date of estimated seroconversion (EDS) were retrospectively evaluated. Median time from EDS to AIDS was analyzed by Kaplan-Meier curves. Hazard ratios were determined by Cox proportional model.

RESULTS

CRF01_AE subtype was predominant (46.0%), especially in the MSM group. Further analysis revealed that the proportion of X4 tropism was higher in the CRF01_AE subtype (45.5%) than in others (C/CRF07_BC/CRF08_BC, 4.3%; B, 6.1%; P <0.001). CRF01_AE subtype was associated with faster progression from EDS to AIDS (4.8 vs. 6.4 years, P = 0.018) compared with non-CRF01_AE subtypes. In a multivariate model, the adjusted hazard ratio (aHR) of CRF01_AE was 1.42 (95% confidence interval, CI 0.99-2.03, P = 0.057), independent of HIV-1 viral load; it was also associated with fast progression to advanced immunodeficiency (aHR, 1.81, 95% CI 1.03-3.18, P = 0.038).

CONCLUSION

CRF01_AE, a predominant HIV-1 subtype in Chinese HIV-1 sexually infected patients, tends to be associated with fast progression to AIDS and advanced immunodeficiency, which might be ascribed to high proportion of X4 tropism. Further investigation of these risk factors may have significant implications to clinical practice and policy-making.

Genotypic prediction of HIV-1 CRF01-AE tropism

HIV-1 subtype CRF01-AE predominates in south Asia and has spread throughout the world. The virus tropism must be determined before using CCR5 antagonists. Genotypic methods could be used, but the prediction algorithms may be inaccurate for non-B subtypes like CRF01-AE and the correlation with the phenotypic approach has not been assessed. We analyzed 61 CRF01-AE V3 clonal sequences of known phenotype from the GenBank database. The sensitivity of the Geno2pheno10 genotypic algorithm was 91%, but its specificity was poor (54%). In contrast, the combined 11/25 and net charge rule was highly specific (98%) but rather insensitive (64%). We thus identified subtype CRF01-AE determinants in the V3 region that are associated with CXCR4 use and developed a new simple rule for optimizing the genotypic prediction of CRF01-AE tropism. The concordance between the predicted CRF01-AE genotype and the phenotype was 95% for the clonal data set. We then validated this algorithm by analyzing the data from 44 patients infected with subtype CRF01-AE, whose tropism was determined using a recombinant phenotypic entry assay and V3-loop bulk sequencing. The CRF01-AE genotypic tool was 70% sensitive and 96% specific for predicting CXCR4 use, and the concordance between genotype and phenotype was 84%, approaching the concordance obtained for predicting the tropism of HIV-1 subtype B. Genotypic predictions that use a subtype CRF01-AE-specific algorithm appear to be preferable for characterizing coreceptor usage both in pathophysiological studies and for ensuring the appropriate use of CCR5 antagonists.

Genetic diversity and molecular epidemiology of HIV transmission

The high genetic diversity of HIV is one of its most significant features, as it has consequences in global distribution, vaccine design, therapy success, disease progression, transmissibility and viral load testing. Studying HIV diversity helps to understand its origins, migration patterns, current distribution and transmission events. New advances in sequencing technologies based on the parallel acquisition of data are now used to characterize within-host and population processes in depth. Additionally, we have seen similar advances in statistical methods designed to model the past history of lineages (the phylodynamic framework) to ultimately gain better insights into the evolutionary history of HIV. We can, for example, estimate population size changes, lineage dispersion over geographic areas and epidemiological parameters solely from sequence data. In this article, we review some of the evolutionary approaches used to study transmission patterns and processes in HIV and the insights gained from such studies.

Phylodynamics of HIV-1 from a phase III AIDS vaccine trial in Bangkok, Thailand

BACKGROUND

In 2003, a phase III placebo-controlled trial (VAX003) was completed in Bangkok, Thailand. Of the 2,546 individuals enrolled in the trial based on high risk for infection through injection drug use (IDU), we obtained clinical samples and HIV-1 sequence data (envelope glycoprotein gene gp120) from 215 individuals who became infected during the trial. Here, we used these data in combination with other publicly available gp120 sequences to perform a molecular surveillance and phylodynamic analysis of HIV-1 in Thailand.

METHODOLOGY AND FINDINGS

Phylogenetic and population genetic estimators were used to assess HIV-1 gp120 diversity as a function of vaccination treatment, viral load (VL) and CD4(+) counts, to identify transmission clusters and to investigate the timescale and demographics of HIV-1 in Thailand. Three HIV-1 subtypes were identified: CRF01_AE (85% of the infections), subtype B (13%) and CRF15_AE (2%). The Bangkok IDU cohort showed more gp120 diversity than other Asian IDU cohorts and similar diversity to that observed in sexually infected individuals. Moreover, significant differences (P<0.02) in genetic diversity were observed in CRF01_AE IDU with different VL and CD4(+) counts. No phylogenetic structure was detected regarding any of the epidemiological and clinical factors tested, although high proportions (35% to 50%) of early infections fell into clusters, which suggests that transmission chains associated with acute infection play a key role on HIV-1 spread among IDU. CRF01_AE was estimated to have emerged in Thailand in 1984.5 (1983-1986), 3-6 years before the first recognition of symptomatic patients (1989). The relative genetic diversity of the HIV-1 population has remained high despite decreasing prevalence rates since the mid 1990s.

CONCLUSIONS

Our study and recent epidemiological reports indicate that HIV-1 is still a major threat in Thailand and suggest that HIV awareness and prevention needs to be strengthened to avoid AIDS resurgence.