Design of small molecules with HIV fusion inhibitory property based on Gp41 interaction assay

Gp41 of HIV [Human Immunodeficiency Virus] is a protein that mediates fusion between viral and cellular membranes. The agent, T-20, which has been approved for HIV inhibition, can restrain Gp41 function in the fusion process; nevertheless, it has disadvantages like instability, high cost of production and injection form to be delivered twice a day. Several molecules like NB-2 and NB-64 have been discovered that can inhibit HIV infection. These molecules were used as template compounds to design and develop more effective small molecules functioning as HIV-1 fusion inhibitors targeting Gp41. The process included in silico docking protocols using HEX and ArgusLab applications. A multisource database was created, after choosing the best molecules; they were tested in vitro for inhibitory activity by HIV-1 single-cycle model, transfected in HEK cells [293T]. Computational analysis and experimental data were combined to explore molecular properties and the most potent ones were found, with the best suitable criteria for interaction with Gp41. Several examples [DAA-6, DAA-9 and DAA-12] could inhibit infection in vitro as effective as NB-2, NB- 64. Since disadvantages of available fusion inhibitor [T-20], it seems necessary to find similar molecules to be approved and have small size providing suitable bioactivity profile. The molecules explored in this study can be good candidates for further investigations to be used as oral HIV fusion inhibitors in the future

Multicenter evaluation of individual donor nucleic acid testing (NAT) for simultaneous detection of human immunodeficiency virus -1 & hepatitis B & C viruses in Indian blood donors.

BACKGROUND & OBJECTIVE: India has a high prevalence of HIV-1, hapatitis C and B virus (HCV and HBV) in the blood donors but has yet to implement nucleic acid testing (NAT) in blood screening. We undertook a multicentre evaluation of blood donor testing by NAT for simultaneous detection of HIV-1, HBV and HCV in a single tube and also to determine the feasibility of NAT implementation in India's low volume setting. METHODS: A total of 12,224 unlinked samples along with their serological results were obtained from representative eight blood banks in India and were individually manually tested by the Procleix Ultrio Assay (Chiron Corp. Emeryville, CA) for simultaneous detection of HIV-1, HCV, and HBV. RESULTS: Of the 12,224 samples tested, 209 (1.71%) were seroreactive. One hundred thirty three samples (1.09%) were reactive by Ultrio assay, 84 samples were seroreactive but NAT non reactive. There were eight NAT yield cases: 1 HIV, 1 HIV-HCV co-infection, and 6 HBV. INTERPRETATION & CONCLUSION: Our observed NAT yield for all three viruses was 1 in 1528 (0.065%). We estimate NAT could interdict 3272 infectious donations a year among our approximate 5 million annual donations.

Chemokine profile among human immunodeficiency virus-1 (HIV-1) infected individuals from southern India.

BACKGROUND & OBJECTIVE: Individuals infected with HIV-1 have higher levels of chemokine producing cells compared to uninfected individuals. It is important to know the changes in chemokine levels associated with rate of progression of disease. There is a paucity of information on the plasma chemokines in HIV-1 infected individuals from India. We therefore carried out this study to estimate the levels of three chemokines namely macrophage inflammatory protein alpha (MIP1alpha), MIP1beta and RANTES, in relation to disease status in HIV-1 infected individuals and compared with uninfected individuals. METHODS: RANTES and MIP1alpha were estimated using ELISA in 114 HIV-1 infected and 30 controls, whereas MIP1beta was estimated in 101 HIV infected individuals only and 30 controls. The values were compared to the T cell subsets, HIV-1 viral loads and plasma cytokines (interferon gamma and interleukin-10). RESULTS: Compared to controls the mean MIP1alpha and RANTES level among the HIV-1 infected individuals was higher while MIP1beta level was lower in HIV infected individuals except CDC C groups. There was a significant positive correlation for MIP1á with HIV-1 viral load and IFNgamma, for MIP1alpha with viral load and IL10. There was a significant negative correlation between MIP1alpha with CD4 count and CD4: CD8 ratio and MIP1beta with CD4 count and CD8 count. There was a negativecorrelation between RANTES values and CD8 per cent. INTERPRETATION & CONCLUSION: In conclusion, our study showed a significantly higher level of beta chemokines in south Indian HIV-1 infected individuals compared to controls. These beta chemokines may have the inhibitory effect on HIV-1 only during the initial period and with the progression of disease this inhibitory effect wanes as shown by the positive correlation of beta chemokines with HIV-1 viral load.

A human mutant CD4 molecule resistant to HIV-1 binding restores helper T-lymphocyte functions in murine CD4-deficient mice

CD4 is a cell surface glycoprotein that acts as a co-receptor for the T cell antigen receptor by binding to a non-polymorphic portion of MHC molecules. CD4 also functions as a receptor for human immunodeficiency virus type-I (HIV-1) because the viral envelope glycoprotein gp120 binds to CD4 with a high affinity. We have previously demonstrated that introduction of mutations into CD4 abolished the binding of gp120 and prevented HIV-1 from entering cells and spreading. However, whether introduction of such mutations into CD4 causes decreased binding to MHC and loss of function is yet to be determined. We generated transgenic mouse lines by injecting a mutant human CD4 (muthCD4) gene under a murine CD4 enhancer/promoter to ensure tissue and stage specific expression. To exclude the influence of endogenous murine CD4, transgenic mice were crossed with murine CD4-targeted mice to produce muthCD4 transgenic mice lacking endogenous CD4 (muthCD4TG/KO mice). In these mice, T lymphocytes expressing muthCD4 expanded and matured in the thymus and were present in the spleen and lymph nodes. They also activated B cells to mount an antibody response to a T-dependent antigen. The results from this study suggest that a human variant of CD4 modified to be resistant to HIV-1 binding can rescue the signaling for T cell development in the thymus in vivo, having helper T cell functions. Thus, further characterization of muthCD4 molecules should open the way to new HIV treatment modalities.

Obstacles to successful antiretroviral treatment of HIV-1 infection: problems & perspectives.

Mutations in human immunodeficiency virus type 1 (HIV-1) are a major impediment to successful highly active antiretroviral therapy (HAART) and the design of anti-HIV vaccines. Although HAART has made long-term suppression of HIV a reality, drug resistance, drug toxicity, drug penetration, adherence to therapy, low levels of continued viral replication in cellular reservoirs and augmentation of host immune responses are some of the most important challenges that remain to be sorted out. Continuing viral replication in the face of HAART leads to the accumulation of drug resistance mutations, increase in viral loads and eventual disease progression. Patients who fail therapy have minimal options for their clinical management. Therefore, a clear understanding of the pathogenesis of drug-resistant HIV-1, and all of the issues that influence the success of HAART is urgently needed. In the present article, we discuss various obstacles to HIV therapy, and provide perspectives relating to these issues that are critical in determining the success or failure of HAART.

Transduction of yeast cytosine deaminase mediated by HIV-1 Tat basic domain into tumor cells induces chemosensitivity to 5-fluorocytosine

Enzyme/prodrug approach is one of the actively developing areas for cancer therapy. In an effort to develop more effective enzyme/prodrug systems, cell-permeable cytosine deaminase was produced by fusing yeast cytosine deaminase (yCD) in frame with RKKRRQRRR domain of HIV-1 Tat which is an efficient delivery peptide of the foreign proteins into cells. The purified Tat-yCD fusion protein expressed in Escherichia coli was readily transduced into mammalian cells in a time- and dose-dependent manner. A significant level of the transduced Tat-yCD protein was recovered in the cell and was stable for 24 h as indicated by both results of the enzymatic assay of 5-fluorocytosine (5-FC) conversion to 5-fluorouracil (5-FU) and Western blot analysis. The cells transduced with Tat-yCD become highly sensitive to the cytotoxicity of 5-FC, while cells treated with yCD are unaffected by 5-FC. In addition, a strong bystander effect was observed with conditioned media from cells transduced with Tat-yCD added to non-transduced cells. Tat-yCD fusion protein demonstrated here for its ability to transduce into cells and convert nontoxic prodrug 5-FC to the toxic antimetabolite 5-FU, may be a useful approach for cancer therapy.

Carga viral en el síndrome de inmunodeficiencia adquirida. Estudio comparativo de tres métodos / Viral load and lymphocyte subpopulations in HIV-1 infection

Se evaluaron simultáneamente tres diferentes pruebas cuantitativas para determinar el ARN plasmático del VIH-1 en 129 pacientes adultos y pediátricos de SIDA (b DNA I Chiron Co), Digene Hybrid Capture Test (Digene Co) y MASBA VIH-1 ARN QT (Organon Teknika). Se efectuó análisis estadístico de varianza. La prueba más sensible de las evaluadas en términos de precisión y reproducibilidad fue la de NASBA. Esta prueba fue también apropiada para pacientes pediátricos dado los pequeños volúmenes de muestra necesarios para realizar el estudio (10 microlitros)

Nucleocytoplasmic transport of proteins and control of cellular function.

Nucleocytoplasmic transport of proteins occurs through pores embedded in the nuclear envelope. Recent studies have defined the cytoplasmic factors required for signal-mediated import of nuclear proteins. Considerable progress has been made in understanding the mechanism of nuclear export of proteins by the identification of specific signal sequences needed for export. Regulatory molecules have been shown to adopt novel mechanisms to control their entry into the nucleus and thereby regulate their functions.

Evaluation of a gp41 synthetic peptide for detection of antibodies anti-HIV1

Un péptido sintético derivado de una región conservada de la glicoproteína de transmembrana gp41 compuesto por 12 aminoácidos fue evaluado abtígeno de fase sólida en un enzimoinmunoensayo. Se analizaron 3 diferentes paneles de suero de Suecia, la Argentina y Tanzania. Se encontró una especificidad del 97.7% y 97.2% para los sueros suecos y argentinos respectivamente, siendo la sensibilidad del 100% para ambos paneles. Para el panel africano la especificidad fue del 90.5% y la sensibilidad del 96.0%. Los resultados indican que este péptido es altamente reactivo con sueros positivos para HIVl y puede ser útil en ensayos de inmunodiagnóstico