scholarly journals Loss of CD4 membrane expression and CD4 mRNA during acute human immunodeficiency virus replication.

1988 ◽  
Vol 168 (6) ◽  
pp. 1953-1969 ◽  
Author(s):  
P Salmon ◽  
R Olivier ◽  
Y Riviere ◽  
E Brisson ◽  
J C Gluckman ◽  
...  
Keyword(s):  
Cell Surface ◽  
Virus Replication ◽  
Receptor Gene ◽  
Human Immunodeficiency Virus Replication ◽  
Hiv Replication ◽  
Membrane Expression ◽  
Receptor Modulation ◽  
Immunodeficiency Virus ◽  
Vaccinia Viruses ◽  
Hiv Envelope

Using mAbs and genomic probe to the CD4 molecule, the HIV receptor, we demonstrated that HIV replication induces the disappearance of its functional receptor from the cell surface by two distinct mechanisms. First, after being expressed onto the cell surface, HIV envelope gp110 will complex CD4, efficiently masking the CD4 epitope used by the virus to bind its receptor. This phenomenon occurs on the surface of each infected cell and is not due to the release of soluble gp110; infection with recombinant HIV/vaccinia viruses expressing a mutated HIV env gene designed to prevent gp110 release from the cell surface induces a similar gp/CD4 complexes formation. Second, virus replication induces a dramatic and rapid loss of CD4 mRNA transcripts, preventing new CD4 molecules from being synthesized. These two mechanisms of receptor modulation could have been developed to avoid reinfection of cells replicating the virus as well as to produce more infectious particles. These results suggest that the classical virus interference documented for other retroviruses might not only be due to receptor/envelope interaction, but might also depend on receptor gene expression.

scholarly journals Partial Inhibition of Human Immunodeficiency Virus Replication by Type I Interferons: Impact of Cell-to-Cell Viral Transfer

2009 ◽  
Vol 83 (20) ◽  
pp. 10527-10537 ◽  
Author(s):  
Daniela Vendrame ◽  
Marion Sourisseau ◽  
Virginie Perrin ◽  
Olivier Schwartz ◽  
Fabrizio Mammano
Keyword(s):  
Human Immunodeficiency Virus ◽  
Virus Replication ◽  
Type I Interferons ◽  
Human Immunodeficiency Virus Replication ◽  
Type I ◽  
Restriction Factors ◽  
Hiv Replication ◽  
Potent Effect ◽  
Immunodeficiency Virus ◽  
The Impact

ABSTRACT Type I interferons (IFN) inhibit several steps of the human immunodeficiency virus type 1 (HIV) replication cycle. Some HIV proteins, like Vif and Vpu, directly counteract IFN-induced restriction factors. Other mechanisms are expected to modulate the extent of IFN inhibition. Here, we studied the impact of IFN on various aspects of HIV replication in primary T lymphocytes. We confirm the potent effect of IFN on Gag p24 production in supernatants. Interestingly, IFN had a more limited effect on HIV spread, measured as the appearance of Gag-expressing cells. Primary isolates displayed similar differences in the inhibition of p24 release and virus spread. Virus emergence was the consequence of suboptimal inhibition of HIV replication and was not due to the selection of resistant variants. Cell-to-cell HIV transfer, a potent means of virus replication, was less sensitive to IFN than infection by cell-free virions. These results suggest that IFN are less active in cell cultures than initially thought. They help explain the incomplete protection by naturally secreted IFN during HIV infection and the unsatisfactory outcome of IFN treatment in HIV-infected patients.

Metabolism of 3′-Azido-3′-Deoxythymidine and 3′-Fluoro-3′-Deoxythymidine in Combination in Human Immunodeficiency Virus Infected Lymphoblastoid Cells

1992 ◽  
Vol 3 (3) ◽  
pp. 165-170 ◽  
Author(s):  
S. Cox
Keyword(s):  
Human Immunodeficiency Virus ◽  
Virus Replication ◽  
Cell Types ◽  
Human Immunodeficiency Virus Replication ◽  
Lymphoblastoid Cells ◽  
Synergistic Inhibition ◽  
Immunodeficiency Virus ◽  
Deoxynucleoside Triphosphate ◽  
The Individual

A combination of 3′-azido-3′-deoxythymidine (AZT) with 3′-fluoro-3′-deoxythymidine (FLT) has been shown previously to give synergistic inhibition of human immunodeficiency virus replication and greatly reduced cytotoxicity in vitro. The phosphorylation of the compounds, and their effect upon the natural deoxynucleoside triphosphate pools, were compared in CEM, H9, and HIV-infected H9 lymphoblastoid cells, both for the compounds when used alone and when combined together. Higher levels of FLT triphosphate than AZT triphosphate, and higher levels of AZT monophosphate than FLT monosphosphate, were formed in all cell types. Both compounds were phosphorylated most efficiently in CEM cells, whereas they were least efficiently phosphorylated in infected H9 cells. Owing to competition, the phosphorylation of both analogues was reduced when used in combination, compared to the phosphorylation of the separate compounds. The phosphorylation of the separate compounds was therefore at a maximum and was not increased by combining the compounds. The two compounds competed equally with each other for phosphorylation when used at a ratio of AZT: FLT of 5: 1. Both analogues severely reduced the deoxynucleoside triphosphate pools in uninfected and human immunodeficiency virus-infected H9 cells, but not in CEM cells. The effects of the two compounds were similar to those found when the compounds were combined, and thus H9 cells were shown to be much more sensitive to the effects of the analogues upon deoxynucleoside triphosphate pools than CEM cells were. Thus the synergistic combination of 3′-azido-3′-deoxythymidine and 3′-fluoro-3′-deoxythymidine was shown to have a similar metabolism and a similar effect upon cellular deoxynucleoside triphosphate pools to the individual compounds.

scholarly journals Variants selected by treatment of human immunodeficiency virus-infected cells with an immunotoxin.

1990 ◽  
Vol 172 (3) ◽  
pp. 745-757 ◽  
Author(s):  
S H Pincus ◽  
K Wehrly ◽  
E Tschachler ◽  
S F Hayes ◽  
R S Buller ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Cell Surface ◽  
Reverse Transcriptase ◽  
Selection Process ◽  
Parental Cell ◽  
Parental Cell Line ◽  
Envelope Gene ◽  
Immunodeficiency Virus ◽  
Human T Lymphocyte ◽  
Hiv Envelope

An immunotoxin has been made by coupling anti-human immunodeficiency virus (HIV) envelope antibody 907 to ricin A chain (907-RAC). 907 recognizes an epitope within the immunodominant PB-1 loop of gp120. Variant cells were selected by cloning persistently infected H9/human T lymphocyte virus IIIB cells in the presence of the immunotoxin. Clones resistant to 907-RAC arose at a frequency of 0.1-1.0%. Seven clones were selected for intensive analysis. When studied, these clones fell into two distinct groups, members of which appeared to be identical, suggesting that the variation arose before the selection process. In contrast to the parent cells, none of the cloned variants produced infectious HIV. The first set of clones, designated the "E" variants, expressed decreased levels of the HIV envelope on the cell surface. However, levels of intracellular HIV antigens and reverse transcriptase were equal to or greater than that of the parental cell line. Radioimmunoprecipitation demonstrated that the gp160 was truncated to 145 kD (gp120 was normal length), capable of binding to CD4, and, unlike normal gp160, was released in its unprocessed form into the cellular supernatant. Sequence analysis demonstrated that a deletion at codon 687 of the envelope gene resulted in the production of this truncated protein. Ultrastructural analysis of E variants demonstrated some budding forms of virus, but also large numbers of HIV within intracellular vesicles. The second set of variants, the "F" series, produced no HIV antigens, reverse transcriptase, nor was there ultrastructural evidence of virus. However, proviral DNA was present. Virus could not be induced with agents known to activate latent HIV. These cells also lacked cell surface CD4 and could not be infected with HIV. These studies demonstrate that variation in HIV can affect the phenotype of the cells carrying the altered virus, allowing for escape from immunologic destruction. The E variants may serve as prototypes for attenuated HIV, which could be used as a vaccine. We have reconstructed the mutation found in the E variants within the infectious HIV clone HXB-2 and demonstrated that the resulting virus retains its noninfectious phenotype.

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