OBJECTIVETo develop an objective bioassay for quantitative detection of HIV-induced cell-cell fusion for screening HIV entry inhibitors.

METHODSHL2/3 cells expressing HIV envelope proteins gp120/gp41, Tat, and other HIV proteins were co-cultured with HeLa-CD4-LTR-beta-gal cells expressing CD4 receptor and HIV LTR triggered reporter gene beta-galactosidase. The enzyme activities of beta-galactosidase were detected by a chromogenic substrate, chlorophenol red-beta-galactopyranoside (CPRG). Specific HIV entry inhibitors were used to validate the established detecting method.

RESULTSNo syncytium was formed by mixing HL2/3 and HeLa-CD4-LTR-beta-gal cells. However, the membrane could be fused and the Tat expressed by HL2/3 cells could bind to HIV LTR on HeLa-CD4-LTR-beta-gal cells and trigger the expression of beta-galactosidase. CPRG allowed quantitative and sensitive detection of the activity of beta-galactosidase. Further studies showed that HIV entry inhibitors could inhibit the activity of beta-galactosidase in a dose-dependent manner.

CONCLUSIONWe have developed a simple, cheap, objective and quantitative non-infectious cell-cell fusion bioassay that can be used to screen for anti-HIV agents targeting the virus entry from natural and synthetic compound libraries.

Biological Assay ; Cell Fusion ; Cell Line ; Coculture Techniques ; Drug Evaluation, Preclinical ; methods ; HIV Envelope Protein gp120 ; metabolism ; HIV Envelope Protein gp41 ; metabolism ; HIV Fusion Inhibitors ; chemistry ; pharmacology ; Humans ; beta-Galactosidase ; metabolism

Constructing eukaryotic expressing vector of pMT/Bip/V5-His A-HIV gp120 and transfecting S2 cells to establish stable gp120-expressing S2 cell line. The gp120 gene of HIV CRF07-BC epidemic in China was amplified by polymerase chain reaction from the recombinant vector PRSV-gp120 and confirmed by DNA sequence analysis. The DNA fragment of HIV gp120 was digested with the restriction endonucleases NcoI and XhoI, then inserted into eukaryotic expressing vector pMT/BiP/V5-His A. A selection vector containing the streptomyces griseochromogenes bsd gene conferring blasticidin resistance was cotransfected into drosophila S2 cells by Cellfectin II reagent. The stable cell line was established following repeated screening by blasticidin. HIV gp120 was purified by a Ni-NTA affinity column followed by molecular sieve chromatography. Recombinant protein was characterized by SDS-PAGE, Western blot and ELISA. The eukaryotic expressing vector pMT/BiP/V5-His A-HIV gp120 was constructed, stable expressing cell line was established, and protein was expressed and purified successfully. This result will contribute to functional study of gp120 and vaccine design against AIDS.
Animals ; Cell Line ; Drosophila ; genetics ; metabolism ; virology ; Gene Expression ; HIV ; genetics ; metabolism ; HIV Envelope Protein gp120 ; genetics ; isolation & purification ; metabolism ; HIV Infections ; virology ; Humans ; Recombinant Proteins ; genetics ; isolation & purification ; metabolism

OBJECTIVENew rationally designed i,i+7-hydrocarbon-stapled peptides that target both HIV-1 assembly and entry have been shown to have antiviral activity against HIV-1 subtypes circulating in Europe and North America. Here, we aimed to evaluate the antiviral activity of these peptides against HIV-1 subtypes predominantly circulating in China.

METHODSThe antiviral activity of three i,i+7-hydrocarbon-stapled peptides, NYAD-36, NYAD-67, and NYAD-66, against primary HIV-1 CRF07_BC and CRF01_AE isolates was evaluated in peripheral blood mononuclear cells (PBMCs). The activity against the CRF07_BC and CRF01_AE Env-pseudotyped viruses was analyzed in TZM-bl cells.

RESULTSWe found that all the stapled peptides were effective in inhibiting infection by all the primary HIV-1 isolates tested, with 50% inhibitory concentration toward viral replication (IC50) in the low micromolar range. NYAD-36 and NYAD-67 showed better antiviral activity than NYAD-66 did. We further evaluated the sensitivity of CRF01_AE and CRF07_BC Env-pseudotyped viruses to these stapled peptides in a single-cycle virus infectivity assay. As observed with the primary isolates, the IC50s were in the low micromolar range, and NYAD-66 was less effective than NYAD-36 and NYAD-67.

CONCLUSIONHydrocarbon-stapled peptides appear to have broad antiviral activity against the predominant HIV-1 viruses in China. This finding may provide the impetus to the rational design of peptides for future antiviral therapy.

Amino Acid Sequence ; Anti-HIV Agents ; chemistry ; pharmacology ; China ; epidemiology ; HIV Envelope Protein gp120 ; genetics ; metabolism ; HIV Infections ; epidemiology ; virology ; HIV-1 ; drug effects ; genetics ; Humans ; Peptides, Cyclic ; administration & dosage ; pharmacology ; Phylogeny

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.
*Virus Internalization ; T-Lymphocytes, Helper-Inducer/*metabolism/*virology ; Protein Binding ; Mutation/genetics ; Mice, Transgenic ; Mice ; Humans ; HIV-1/*metabolism ; HIV Envelope Protein gp120/metabolism ; Antigens, CD4/*genetics/*metabolism ; Animals

OBJECTIVETo screen human monoclonal Fab fragments against HIV-1 gp120 peptide binding chemokine receptor.

METHODSA synthesized polypeptide containing 23 amino acid residues of the gp120 antigen epitope binding chemokine receptor was coated as the solid-phase antigen. After biopanning from the HIV-1 phage Fab antibody library, the acquired positive clones were tested and sequenced.

RESULTSOne clone of human phage Fab monoclonal antibody against HIV-1 gp120 polypeptide was acquired. It has high affinity, specificity and inhibition rate and it belongs to IgG I subclass and kappa type. Its Vh H and V kappa were derived from Vh III and V kappa III.

CONCLUSIONSThe human phage Fab fragment against HIV-1 gp120 antigen site binding chemokine receptor was acquired.

Amino Acid Sequence ; Antibodies, Monoclonal ; genetics ; Antibodies, Viral ; genetics ; Bacteriophages ; genetics ; Cloning, Molecular ; HIV Envelope Protein gp120 ; Humans ; Immunoglobulin Fab Fragments ; genetics ; In Vitro Techniques ; Molecular Sequence Data ; Peptide Library ; Receptors, Chemokine ; metabolism ; Receptors, HIV ; immunology

Complete HIV-1 env genes were amplified by nested PCR from uncultured peripheral blood mononuclear cells (PBMCs) DNA of 60 HIV-1 positive paid blood donors in Henan province, and the amplified full-length genes were sequenced. Twenty one full-length env genes were obtained, sequence analysis found that 15 of them had intact open reading frame (ORF). Fourteen sequences conformed to subtype B', their average genetic distance with the international reference sequence RL42 was 4.87% +/- 0.31%. One was subtype B, its genetic distance with the international reference sequence HXB2 was 5.43%. The amino acid sequences of these env genes were deduced according to their nucleotide sequences and extensive analysis and comparison of important structural motifs were performed. The results indicated that there was no drastic alteration in the number and position of potential N-linked glycosylation sites among these 15 sequences. And the residues involved in forming the CD4 binding site were highly conserved. Genotype prediction of coreceptor usage based on V3 sequence and net charge suggested that most samples use CCR5 coreceptor. GPGR motif at the tetrapeptide crown in the V3 loop was most common in these samples and it was detected in 40% sequences. The cleavage site of gp120/gp41 was highly conserved, so Gp160 precursor of all isolates would be efficiently cleaved into the Gp120 and Gp41 subunits. The known neutralizing antibody binding sites for 2G12, IgG1b12, 4E10 and 2F5 were also highly conserved, it is expected that most of these isolates will be sensitive to neutralization by these antibodies. Further study to elucidate the correlation of the env genotype to functionally relevant motifs is necessary and that will aid vaccine and novel drug design.
Base Sequence ; Blood Donors ; supply & distribution ; CD4 Antigens ; metabolism ; China ; Clinical Laboratory Techniques ; Conserved Sequence ; HIV Envelope Protein gp120 ; genetics ; HIV-1 ; genetics ; Humans ; Receptors, CCR5 ; chemistry ; genetics ; env Gene Products, Human Immunodeficiency Virus ; chemistry ; genetics

Anti-HIV-1 gp120 single chain antibody(scFv) gene and staphylococcus extoxin A(SEA) gene were inserted into vector pPIC9K. The recombinant plasmid was integrated into Pichia pastoris by electroporation. High level expression was performed by determining the Muts phenotype and screening muti-copy integrants. The recombinant protein was about 57kD and the production was 50.1 mg/L. It was shown that the two kinds of protein affected the conformation of each other by antibody affinity assay, but the recombinant targeting toxins could highly mediate CTLs to kill HIV-1 target cells.
Enterotoxins ; genetics ; Genetic Vectors ; HIV Envelope Protein gp120 ; biosynthesis ; genetics ; immunology ; HIV-1 ; genetics ; immunology ; Immunoglobulin Variable Region ; biosynthesis ; genetics ; immunology ; Pichia ; genetics ; metabolism ; Recombinant Proteins ; biosynthesis ; genetics ; immunology

BACKGROUNDHIV-1 infected and immune-activated macrophages and microglia secrete neurotoxins, such as tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), which play major role in the neuronal death. It has been shown that different HIV-1 variants have varying abilities to elicit secretion of TNF-α by peripheral blood mononuclear cell (PBMC); however, whether the difference of gp120 gene could affect the secretion of TNF-α and IL-1β by glial cells is unknown. The aim of this study was to explore the association between gene diversity and induction of neurotoxic cytokines.

METHODSIn this study, we constructed retroviral vectors MSCV-IRES-GFP/gp120 using HIV-1 gp120 genes isolated from four different tissues of one patient who died of AIDS dementia complex (ADC). Recombinant retroviruses produced by cotransfection of MSCV-IRES-GFP/gp120, pCMV-VSV-G and pUMVC into 293T cells were collected and added into U87 glial cells. Concentrations of TNF-α and IL-1β secreted by transduced U87 cells were assayed with ELISA separately.

RESULTSThe four HIV-1 gp120 were in the different branch of the neighbor-joining tree. Compared to the pMIG retrovirus (gp120-negative) or U87 cells, all the gp120-positive recombinant retroviruses induced more TNF-α (P < 0.01) and IL-1β (P < 0.01). In addition, compared with the L/MIG retrovirus, all the three brain gp120-positive recombinant retroviruses induced less TNF-α (P < 0.01) and IL-1β (P < 0.01).

CONCLUSIONSHIV-1 gp120 could induce U87 cells secret more TNF-α and IL-1β again. The more important is that difference of HIV-1 gp120, especially cell-tropism may account for the different ability in eliciting secretion of TNF-α and IL-1β, which might supply a novel idea helping understand the pathogenesis of ADC.

AIDS Dementia Complex ; metabolism ; virology ; Cell Line ; Cell Line, Tumor ; Enzyme-Linked Immunosorbent Assay ; HIV Envelope Protein gp120 ; genetics ; metabolism ; Humans ; Interleukin-1beta ; metabolism ; Tumor Necrosis Factor-alpha ; metabolism

BACKGROUNDThe human immunodeficiency virus-1 (HIV-1) envelope glycoprotein gp120 has been implicated in the development of AIDS-associated retinopathy. The present study tested the hypothesis that gp120 may induce oxidative stress including up regulation of inducible nitric oxide synthase (iNOS) and production of malondialdehyde (MDA) and nitric oxide (NO) to mediate retinopathy in retinal pigment epithelial (RPE) cells.

METHODSHuman RPE cell line D407 was cultured and treated with gp120. HIV-1 gp120 protein induced lipid peroxidation product MDA. NO production and iNOS expression were examined in vitro by spectrophomtometry, real-time PCR, Western blotting, and confocal microscope.

RESULTSAddition of gp120 was able to induce RPE cells to produce NO and MDA in time- and dose-dependent manners (P < 0.05). Similarly, gp120 was also capable of up-regulating iNOS mRNA and protein in D407 cells in time- and dose-dependent manners.

CONCLUSIONSGp120 induces oxidative stress in D407 cell by stimulating MDA and NO production, which is mediated by up-regulating iNOS expression. Gp120 may mediate oxidation stress in AIDS-associated retinopathy.

Blotting, Western ; Cell Line ; Epithelial Cells ; drug effects ; metabolism ; HIV Envelope Protein gp120 ; pharmacology ; Humans ; Immunohistochemistry ; Microscopy, Confocal ; Nitric Oxide ; metabolism ; Nitric Oxide Synthase Type II ; genetics ; metabolism ; Oxidative Stress ; drug effects ; Polymerase Chain Reaction ; Retina ; cytology

OBJECTIVETo prepare HIV-1 subtype C Gp120 protein and to produce its polyclonal antibodies.

METHODSA C-terminal fragment of gp120 gene was amplified by PCR from a plasmid expressing full-length HIV-1 subtype C gp160 gene. The length of the subtype C gp120 fragment was 612 nt and it encodes 204 amino acid residues. The resulting DNA construct was cloned into a prokaryotic expression vector (pET-30a) and recombinant pET-30a-gp120 was expressed in Escherichia coli BL21 (DE3) as an insoluble protein. The vector also contained a six-histidine (His6) tag at the C-terminus for convenient purification. To produce subtype C Gp120-specific polyclonal antibodies, New-Zealand rabbit was immunized with the purified Gp120 protein. Serum samples were tested by enzyme-linked immunosorbent assays (ELISA) to determine the level of antibodies. And Western blotting was used to further verify whether the polyclonal antibodies could specifically recognize subtype C Gp160 protein expressed in mammalian cells.

RESULTSHIV-1 subtype C Gp120 protein was successfully acquired and the titer of its polyclonal antibodies was 1:204 800. The polyclonal antibodies efficiently recognized Subtype C Gp160 protein expressed in COS-1 cells.

CONCLUSIONHIV-1 subtype C Gp120 fusion protein with high purity was obtained and its corresponding polyclonal antibodies with high titer were produced.

Animals ; Antibodies, Viral ; analysis ; COS Cells ; Cercopithecus aethiops ; Escherichia coli ; genetics ; metabolism ; Gene Expression ; HIV Envelope Protein gp120 ; genetics ; immunology ; isolation & purification ; Rabbits ; Recombinant Proteins ; genetics ; immunology ; isolation & purification