Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.3.1.28 (chloramphenicol acetyltransferase)
 5,100 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The tat gene of the human immunodeficiency virus, tat-III, when introduced into T-lymphoblastoid Jurkat cells by a Moloney retroviral recombinant DNA vector expressed high levels of the functional tat protein as measured by the chloramphenicol acetyltransferase assay. Immunofluorescence analysis with CD4-specific monoclonal antibodies demonstrated that the cell surface levels of the CD4 antigen were increased by 5- to 10-fold in the tat-III-infected Jurkat cells. Cellular cytoplasmic RNA analysis indicated that the enhanced CD4 expression was mediated at the mRNA level. Our findings suggest that the single expression of the human immunodeficiency virus tat protein in the absence of the other viral proteins causes an upregulation of CD4 gene expression on helper T cells, although infection of these cells by the virus, thus expressing all the viral gene products including tat, is known to downregulate CD4 antigen expression.
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PMID:Increased expression of CD4 molecules on Jurkat cells mediated by human immunodeficiency virus tat protein. 284 47

We recently demonstrated that monoclonal antibody (MAb) 13B8-2, specific for the immunoglobulin (Ig) complementary determining region 3 (CDR3)-like region of the CD4 molecule, inhibits viral transcription in human immunodeficiency virus (HIV)-infected CEM cells and HIV type 1 (HIV-1) promoter activity. Here, we have studied the capacity of several MAb specific for the D1 domain of CD4, including anti-CDR2-like (Leu-3a and ST4) and anti-CDR3-like (13B8-2 and ST40) MAb, and for the D2 domain of CD4 (BL4) to inhibit both provirus transcription in HIV-1LAI-infected CEM cells and transcription of the chloramphenicol acetyltransferase (CAT) gene under control of the HIV-1 long terminal repeat in transiently transfected CEM cells. We found that HIV-1 promoter activity and provirus transcription are inhibited only by MAb that bind to the CDR3-like region in domain 1 of CD4. Moreover, we demonstrated that the Fab fragment of an anti-CDR3-like region-specific anti-CD4 MAb is a powerful inhibitor of HIV-1 promoter activity. These results have implications for understanding the role of the CDR3-like region in CD4 T-cell signaling, which controls provirus transcription.
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PMID:Functional epitope analysis of the human CD4 molecule: antibodies that inhibit human immunodeficiency virus type 1 gene expression bind to the immunoglobulin CDR3-like region of CD4. 747 6

We used the polymerase chain reaction (PCR) to study which step(s) of the human immunodeficiency virus type 1 (HIV-1) life cycle may be blocked following treatment of HIV-exposed CEM cells with 13B8-2, a monoclonal antibody (mAb) specific for the immunoglobulin (Ig) CDR3-like region of the CD4 molecule and able to inhibit the productive infection of CEM cells by HIV-1. The presence of viral RNA was investigated and found in 13B8-2 mAb-treated CEM cells 30 min after viral exposure; the full-length viral DNA was found at 24 h post-infection. We also found integrated forms of viral DNA at 24 h post-infection. However, the integrated provirus was transcriptionally inactive in 13B8-2 mAb-treated cells, as demonstrated by the absence of spliced HIV-1 mRNA. The lack of HIV transcription under 13B8-2 mAb treatment was confirmed by chloramphenicol acetyltransferase (CAT) assay. We conclude that the inhibition of viral gene transcription accounts for the lack of progeny virions in culture supernatants of cells treated with this anti-CD4 mAb. We also demonstrate that 13B8-2 blocks viral production from chronically infected cells and restores CD4 cell-surface expression on CEM cells containing an integrated provirus(es). We found this effect to be reversible. Moreover, we demonstrate that 13B8-2 mAb treatment is efficient on different HIV-1 and HIV-2 virus isolates. These results may have major implications for the treatment of AIDS.
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PMID:An antibody that binds the immunoglobulin CDR3-like region of the CD4 molecule inhibits provirus transcription in HIV-infected T cells. 750 20