Abstract
Increased levels of inflammatory cytokines, including tumor necrosis factor (TNF), interleukin-1 (IL-1), and IL-6, have been detected in specimens from human immunodeficiency virus type 1 (HIV-1)-infected individuals. Here we demonstrate that HIV-1 activates the expression of TNF but not of IL-1 and IL-6 in acutely and chronically infected T cells. The increase in TNF gene expression is due to activation of the TNF promoter by the viral gene product Tat. Transactivation of TNF gene expression requires the product of the first exon of the tat gene and is cell type independent. T cells chronically infected with pol-defective HIV-1 provirus constitutively express both Tat and TNF at levels significantly higher (fivefold) than those seen in control cells, and treatment with phorbol myristate acetate greatly enhances Tat expression and TNF production. As TNF can increase the production of IL-1 and IL-6 and these inflammatory cytokines all enhance HIV-1 gene expression and affect the immune, vascular, and central nervous systems, the activation of TNF by Tat may be part of a complex pathway in which HIV-1 uses viral products and host factors to increase its own expression and infectivity and to induce disease.
MeSH terms
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Animals
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Base Sequence
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Blotting, Northern
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Cell Line
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Chloramphenicol O-Acetyltransferase / genetics
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Chloramphenicol O-Acetyltransferase / metabolism
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Cytokines / biosynthesis*
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Cytokines / genetics
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Enzyme-Linked Immunosorbent Assay
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Gene Expression
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Gene Expression Regulation, Viral*
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Gene Products, tat / genetics*
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Genes, tat*
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HIV-1 / genetics
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HIV-1 / physiology*
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Humans
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Inflammation
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Interleukin-1 / biosynthesis
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Interleukin-1 / genetics
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Interleukin-6 / biosynthesis
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Interleukin-6 / genetics
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Lymphotoxin-alpha / biosynthesis
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Lymphotoxin-alpha / genetics
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Molecular Sequence Data
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Oligodeoxyribonucleotides
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Oligonucleotides, Antisense
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Plasmids
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Polymerase Chain Reaction
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RNA / genetics
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RNA / isolation & purification
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RNA, Messenger / genetics
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RNA, Messenger / metabolism
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Recombinant Proteins / metabolism
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Transcription, Genetic
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Transfection
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Tumor Cells, Cultured
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Tumor Necrosis Factor-alpha / biosynthesis
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Tumor Necrosis Factor-alpha / genetics
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tat Gene Products, Human Immunodeficiency Virus
Substances
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Cytokines
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Gene Products, tat
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Interleukin-1
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Interleukin-6
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Lymphotoxin-alpha
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Oligodeoxyribonucleotides
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Oligonucleotides, Antisense
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RNA, Messenger
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Recombinant Proteins
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Tumor Necrosis Factor-alpha
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tat Gene Products, Human Immunodeficiency Virus
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RNA
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Chloramphenicol O-Acetyltransferase