201
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McManus CM, Weidenheim K, Woodman SE, Nunez J, Hesselgesser J, Nath A, Berman JW. Chemokine and chemokine-receptor expression in human glial elements: induction by the HIV protein, Tat, and chemokine autoregulation. THE AMERICAN JOURNAL OF PATHOLOGY 2000; 156:1441-53. [PMID: 10751368 PMCID: PMC1876886 DOI: 10.1016/s0002-9440(10)65013-4] [Citation(s) in RCA: 142] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Human immunodeficiency virus (HIV) encephalitis is a prominent pathology seen in children infected with HIV. Immunohistochemical analyses of pediatric brain tissue showed distinct differences in expression of C-C chemokines and their receptors between children with HIV encephalitis and those with non-CNS-related pathologies. Evidence suggests that soluble factors such as HIV Tat released from HIV-infected cells may have pathogenic effects. Our results show Tat effects on chemokines and their receptors in microglia and astrocytes as well as chemokine autoregulation in these cells. These results provide evidence for the complex interplay of Tat, chemokines, and chemokine receptors in the inflammatory processes of HIV encephalitis and illustrate an important new role for chemokines as autocrine regulators.
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Affiliation(s)
- C M McManus
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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202
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Pauza CD, Trivedi P, Wallace M, Ruckwardt TJ, Le Buanec H, Lu W, Bizzini B, Burny A, Zagury D, Gallo RC. Vaccination with Tat toxoid attenuates disease in simian/HIV-challenged macaques. Proc Natl Acad Sci U S A 2000; 97:3515-9. [PMID: 10725402 PMCID: PMC16271 DOI: 10.1073/pnas.97.7.3515] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Tat protein is essential for HIV type 1 (HIV-1) replication and may be an important virulence factor in vivo. We studied the role of Tat in viral pathogenesis by immunizing rhesus macaques with chemically inactivated Tat toxoid and challenging these animals by intrarectal inoculation with the simian/human immunodeficiency virus 89.6PD. Immune animals had significantly attenuated disease with lowered viral RNA, interferon-alpha, and chemokine receptor expression (CXCR4 and CCR5) on CD4(+) T cells; these features of infection have been linked to in vitro effects of Tat and respond similarly to extracellular Tat protein produced during infection. Immunization with Tat toxoid inhibits key steps in viral pathogenesis and should be included in therapeutic or preventive HIV-1 vaccines.
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Affiliation(s)
- C D Pauza
- Department of Pathology and Laboratory Medicine, University of Wisconsin and Wisconsin Regional Primate Research Center, Madison, WI 53706, USA.
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203
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Vaccination with tat toxoid attenuates disease in simian/HIV-challenged macaques. Proc Natl Acad Sci U S A 2000. [PMID: 10725402 PMCID: PMC16271 DOI: 10.1073/pnas.070049797] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Tat protein is essential for HIV type 1 (HIV-1) replication and may be an important virulence factor in vivo. We studied the role of Tat in viral pathogenesis by immunizing rhesus macaques with chemically inactivated Tat toxoid and challenging these animals by intrarectal inoculation with the simian/human immunodeficiency virus 89.6PD. Immune animals had significantly attenuated disease with lowered viral RNA, interferon-alpha, and chemokine receptor expression (CXCR4 and CCR5) on CD4(+) T cells; these features of infection have been linked to in vitro effects of Tat and respond similarly to extracellular Tat protein produced during infection. Immunization with Tat toxoid inhibits key steps in viral pathogenesis and should be included in therapeutic or preventive HIV-1 vaccines.
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204
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205
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Shutt DC, Soll DR. HIV-induced T-cell syncytia release a two component T-helper cell chemoattractant composed of Nef and Tat. J Cell Sci 1999; 112 ( Pt 22):3931-41. [PMID: 10547354 DOI: 10.1242/jcs.112.22.3931] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Using a newly developed gradient chamber to provide independent measurements of chemokinesis (stimulated motility) and chemotaxis (stimulated motility up a concentration gradient) of individual T-helper cells, it was recently demonstrated that HIV-induced T-cell syncytia release two distinct chemotactic activities that are separable by their rates of diffusion. The molecular masses of the two chemoattractant activities were estimated to be 30 and 120 kDa. The higher molecular mass activity was demonstrated to be the viral glycoprotein gp120. In an attempt to identify the lower molecular mass activity, chemotaxis and chemokinesis of T-helper cells were analyzed in individual concentration gradients of the virally encoded proteins Rev, p24, Tat and Nef. None functioned alone as a chemoattractant, but both Tat and Nef alone functioned as chemokinetic stimulants. When Tat and Nef were used together to generate parallel gradients, they stimulated chemotaxis. Antibody to either Tat or Nef neutralized the lower molecular mass chemotactic activity released by syncytia. The addition of antibody to the CD4 receptor or the addition of soluble CD4 inhibited high molecular mass chemotactic activity but not the low molecular mass chemotactic activity in HIV-induced syncytium-conditioned medium, demonstrating that the former but not the latter activity is mediated through the CD4 receptor. These results identify the combination of Nef and Tat as the lower molecular mass T cell chemoattractant released by HIV-induced syncytia, and provide the first evidence suggesting that parallel concentration gradients of two proteins are necessary for chemotaxis.
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MESH Headings
- CD4 Antigens/physiology
- Cells, Cultured
- Chemotactic Factors/chemistry
- Chemotactic Factors/metabolism
- Chemotactic Factors/pharmacology
- Chemotaxis/drug effects
- Culture Media, Conditioned/chemistry
- Drug Synergism
- Gene Products, nef/metabolism
- Gene Products, nef/pharmacology
- Gene Products, tat/metabolism
- Gene Products, tat/pharmacology
- Giant Cells/metabolism
- Giant Cells/virology
- HIV-1
- Humans
- T-Lymphocytes/cytology
- T-Lymphocytes/metabolism
- T-Lymphocytes/virology
- T-Lymphocytes, Helper-Inducer/cytology
- T-Lymphocytes, Helper-Inducer/drug effects
- T-Lymphocytes, Helper-Inducer/virology
- nef Gene Products, Human Immunodeficiency Virus
- tat Gene Products, Human Immunodeficiency Virus
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Affiliation(s)
- D C Shutt
- Department of Biological Sciences, University of Iowa, Iowa City, Iowa 52242, USA
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206
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Biancone L, Cantaluppi V, Boccellino M, Bussolati B, Del Sorbo L, Conaldi PG, Albini A, Toniolo A, Camussi G. Motility induced by human immunodeficiency virus-1 Tat on Kaposi's sarcoma cells requires platelet-activating factor synthesis. THE AMERICAN JOURNAL OF PATHOLOGY 1999; 155:1731-9. [PMID: 10550329 PMCID: PMC1866979 DOI: 10.1016/s0002-9440(10)65488-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
In the present study, we evaluated whether motility of Kaposi's sarcoma (KS) spindle cells induced by HIV-1 Tat protein is dependent on the synthesis of platelet-activating factor (PAF). The results obtained indicate that Tat induced a dose-dependent synthesis of PAF from KS cells at a concentration as low as 0.1 ng/ml. PAF production started rapidly after Tat stimulation, peaking at 30 minutes and declining thereafter. Tat-induced cell migration was also a rapid event starting at 30 minutes. The motility was abrogated by addition of a panel of chemically unrelated PAF receptor antagonists (WEB 2170, CV 3988, CV 6209, and BN 52021), suggesting that the synthesized PAF mediates the motogenic effect of Tat. This effect was also present on cells plated on a type-I collagen-, fibronectin-, or basement membrane extract-coated surface. Expression of PAF receptor-specific mRNA was detected in KS cells. In addition, examination of the cytoskeletal organization showed that Tat-mediated KS cell redistribution of actin filaments and shape change was also inhibited by a PAF receptor antagonist. Moreover, PAF receptor blockade prevented the up-regulation of beta1 integrin and the down-regulation of alphavbeta3 observed after stimulation of KS cells with Tat. In conclusion, the results of the present study indicate that Tat-induced PAF synthesis plays a critical role in triggering the events involved in motility of KS cells.
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Affiliation(s)
- L Biancone
- Cattedra di Nefrologia, Dipartimento di Medicina Interna, Università di Torino, Torino, Italy
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207
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Yang D, Chertov O, Bykovskaia SN, Chen Q, Buffo MJ, Shogan J, Anderson M, Schröder JM, Wang JM, Howard OM, Oppenheim JJ. Beta-defensins: linking innate and adaptive immunity through dendritic and T cell CCR6. Science 1999; 286:525-8. [PMID: 10521347 DOI: 10.1126/science.286.5439.525] [Citation(s) in RCA: 1293] [Impact Index Per Article: 51.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Defensins contribute to host defense by disrupting the cytoplasmic membrane of microorganisms. This report shows that human beta-defensins are also chemotactic for immature dendritic cells and memory T cells. Human beta-defensin was selectively chemotactic for cells stably transfected to express human CCR6, a chemokine receptor preferentially expressed by immature dendritic cells and memory T cells. The beta-defensin-induced chemotaxis was sensitive to pertussis toxin and inhibited by antibodies to CCR6. The binding of iodinated LARC, the chemokine ligand for CCR6, to CCR6-transfected cells was competitively displaced by beta-defensin. Thus, beta-defensins may promote adaptive immune responses by recruiting dendritic and T cells to the site of microbial invasion through interaction with CCR6.
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MESH Headings
- Antibodies/immunology
- Binding, Competitive
- Cell Line
- Chemokine CCL20
- Chemokines, CC/metabolism
- Chemokines, CC/pharmacology
- Chemotaxis
- Chemotaxis, Leukocyte
- Defensins
- Dendritic Cells/immunology
- Humans
- Immunity, Active
- Immunity, Innate
- Immunologic Memory
- Macrophage Inflammatory Proteins
- Pertussis Toxin
- Proteins/pharmacology
- Proteins/physiology
- Receptors, CCR6
- Receptors, Chemokine/genetics
- Receptors, Chemokine/metabolism
- Recombinant Proteins/pharmacology
- T-Lymphocyte Subsets/immunology
- Transfection
- Virulence Factors, Bordetella/pharmacology
- beta-Defensins
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Affiliation(s)
- D Yang
- Laboratory of Molecular Immunoregulation, Division of Basic Sciences, Intramural Research Support Program, SAIC Frederick, National Cancer Institute-Frederick Cancer Research and Development Center, Frederick, MD 21702-1201, USA
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208
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Jeang KT, Xiao H, Rich EA. Multifaceted activities of the HIV-1 transactivator of transcription, Tat. J Biol Chem 1999; 274:28837-40. [PMID: 10506122 DOI: 10.1074/jbc.274.41.28837] [Citation(s) in RCA: 341] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Affiliation(s)
- K T Jeang
- Laboratory of Molecular Microbiology, NIAID, National Institutes of Health, Bethesda, Maryland 20892, USA.
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209
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DeLuca C, Kwon H, Lin R, Wainberg M, Hiscott J. NF-kappaB activation and HIV-1 induced apoptosis. Cytokine Growth Factor Rev 1999; 10:235-53. [PMID: 10647779 DOI: 10.1016/s1359-6101(99)00015-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
HIV infection leads to the progressive loss of CD4+ T cells and the near complete destruction of the immune system in the majority of infected individuals. High levels of viral gene expression and replication result in part from the activation of NF-kappaB transcription factors, which in addition to orchestrating the host inflammatory response also activate the HIV-1 long terminal repeat. NF-kappaB induces the expression of numerous cytokine, chemokine, growth factor and immunoregulatory genes, many of which promote HIV-1 replication. Thus, NF-kappaB activation represents a double edged sword in HIV-1 infected cells, since stimuli that induce an NF-kappaB mediated immune response will also lead to enhanced HIV-1 transcription. NF-kappaB has also been implicated in apoptotic signaling, protecting cells from programmed cell death under most circumstances and accelerating apoptosis in others. Therefore, activation of NF-kappaB can impact upon HIV-1 replication and pathogenesis at many levels, making the relationship between HIV-1 expression and NF-kappaB activation multi-faceted. This review will attempt to analyse the many faces and functions of NF-kappaB in the HIV-1 lifecycle.
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Affiliation(s)
- C DeLuca
- Lady Davis Institute for Medical Research, Department of Microbiology, McGill AIDS Center, McGill University, Montreal, Canada
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210
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Abstract
Chemokines and chemokine receptors play a critical role in the host defense against viruses by mobilizing leukocytes to sites of infection, injury and inflammation. In order to replicate successfully within their host organisms, viruses have devised novel strategies for exploiting or subverting chemokine networks. This review summarizes various mechanisms that are currently known to be used by viruses for modulating chemokine activities including viral homologs of chemokines and chemokine receptors and soluble viral chemokine binding proteins. Insight into these strategies is providing a wealth of information on viral-host interactions, the function of chemokines in host defense and may help to generate novel anti-chemokine agents for treating against viral diseases or inflammatory disorders.
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Affiliation(s)
- A S Lalani
- Howard Hughes Medical Institute and Department of Microbiology and Immunology, University of California San Francisco, 94143-0414, USA.
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211
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Génin P, Mamane Y, Kwon H, LePage C, Wainberg MA, Hiscott J. Differential regulation of CC chemokine gene expression in human immunodeficiency virus-infected myeloid cells. Virology 1999; 261:205-15. [PMID: 10497106 DOI: 10.1006/viro.1999.9852] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The importance of chemokine expression on HIV infection has been emphasized by the discovery that infection of CD4(+) T cells by M-tropic strains of HIV-1 is antagonized by the chemokines RANTES, MIP-1alpha, and MIP-1beta, which are natural ligands of CCR5, a major coreceptor for macrophagetropic (M-tropic) isolates of HIV-1. Similarly, the CCR2b ligands MCP-1 and MCP-3 inhibit productive infection of PBMCs by both CCR5- and CXCR4-dependent strains of HIV-1, suggesting that expression of the MCP-1 chemokine may affect HIV infection via signaling through the CCR2 receptor and subsequent desensitization of the CCR5 and/or CXCR4 signaling pathway. Given the major role played by chemokine receptors in HIV-1 fusion/entry and the regulatory effects of chemokines on HIV-1 infection, we examined the pattern of chemokine gene expression in HIV-1-infected myeloid cells and in primary monocyte/macrophages. Chronic HIV-1 infection of U937 monocytic cells increased the expression of RANTES, MIP-1alpha, MIP-1beta, and IL-8 chemokine genes, but strongly inhibited PMA/PHA- and TNFalpha-induced MCP-1 gene transcription. HIV-1-mediated inhibition of MCP-1 transcription and secretion was further confirmed in de novo HIV-1-infected U937 cells and correlated with a delay in HIV- and signal-induced NF-kappaB binding to the MCP-1 promoter. The inhibition of MCP-1 gene expression may provide a mechanism by which HIV-1 escapes the early influence of chemokine expression in monocytic cells.
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Affiliation(s)
- P Génin
- Lady Davis Institute for Medical Research, McGill University, Montreal, H3T 1E2, Canada
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212
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Koedel U, Kohleisen B, Sporer B, Lahrtz F, Ovod V, Fontana A, Erfle V, Pfister HW. HIV Type 1 Nef Protein Is a Viral Factor for Leukocyte Recruitment into the Central Nervous System. THE JOURNAL OF IMMUNOLOGY 1999. [DOI: 10.4049/jimmunol.163.3.1237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
Recombinant HIV-1 Nef protein, but not Tat, gp120, and gp160, provoked leukocyte recruitment into the CNS in a rat model. The strong reduction of bioactivity by heat treatment of Nef, and the blocking effect of the mAb 2H12, which recognizes the carboxy-terminal amino acid (aa) residues 171–190 (but not of mAb 3E6, an anti-Nef Ab of the same isotype, which maps the aa sequence 168–175, as well as a mixture of mAbs to CD4) provided evidence for the specificity of the observed Nef effects. Using a modified Boyden chamber technique, Nef exhibited chemotactic activity on mononuclear cells in vitro. Coadministration of the anti-Nef mAb 2H12, as well as treatment of Nef by heat inhibited Nef-induced chemotaxis. Besides soluble Nef, chemotaxis was also induced by a Nef-expressing human astrocytoma cell line, but not by control cells. These data suggest a direct chemotactic activity of soluble Nef. The detection of elevated levels of IL-6, TNF-α, and IFN-γ in rat cerebrospinal fluid 6 h after intracisternal Nef injection hint at the additional involvement of indirect mechanisms in Nef-induced leukocyte migration into rat CNS. These data propose a mechanism by which HIV-1 Nef protein may be essential for AIDS neuropathogenesis, as a mediator of the recruitment of leukocytes that may serve as vehicles of the virus and perpetrators for disease through their production of neurotoxins.
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Affiliation(s)
- Uwe Koedel
- *Department of Neurology, Klinikum Grosshadern, Ludwig-Maximilians-University of Munich, Munich, Germany
| | - Birgit Kohleisen
- †Institute of Molecular Virology, GSF-Research Center for Environment and Health Neuherberg, Neuherberg; Germany,
| | - Bernd Sporer
- *Department of Neurology, Klinikum Grosshadern, Ludwig-Maximilians-University of Munich, Munich, Germany
| | - Fritz Lahrtz
- ‡Institute of Biomedical Sciences, University of Tampere, Tampere, Finland; and
| | - Vladimir Ovod
- ‡Institute of Biomedical Sciences, University of Tampere, Tampere, Finland; and
| | - Adriano Fontana
- §Institute of Clinical Immunology, University Hospital Zürich, Zürich, Switzerland
| | - Volker Erfle
- †Institute of Molecular Virology, GSF-Research Center for Environment and Health Neuherberg, Neuherberg; Germany,
| | - Hans-Walter Pfister
- *Department of Neurology, Klinikum Grosshadern, Ludwig-Maximilians-University of Munich, Munich, Germany
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213
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Kameoka M, Tanaka Y, Ota K, Itaya A, Yamamoto K, Yoshihara K. HIV-1 Tat protein is poly(ADP-ribosyl)ated in vitro. Biochem Biophys Res Commun 1999; 261:90-4. [PMID: 10405328 DOI: 10.1006/bbrc.1999.0964] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Purified recombinant HIV-1 Tat protein stimulated acceptor-dependent reaction of poly(ADP-ribose) polymerase in a dose-dependent manner. Analysis of the reaction products by SDS-polyacrylamide gel electrophoresis followed by immunoblotting with anti-poly(ADP-ribose) antibody revealed that recombinant Tat proteins were covalently modified with poly(ADP-ribose) in the enzyme reaction. Eventhough no significant effect of the modification was detected in the activity of Tat to form a specific complex with TAR (a viral transactivation response element) RNA, the present results raise the possibility that poly(ADP-ribose) polymerase is involved in the regulation of HIV-1 through the modification of a virus-encoded transactivator, Tat protein.
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Affiliation(s)
- M Kameoka
- Department of Biochemistry, Nara Medical University, Nara, Kashihara, 634-8521, Japan
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214
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Gallo RC. Tat as one key to HIV-induced immune pathogenesis and Tat (correction of Pat) toxoid as an important component of a vaccine. Proc Natl Acad Sci U S A 1999; 96:8324-6. [PMID: 10411869 PMCID: PMC33620 DOI: 10.1073/pnas.96.15.8324] [Citation(s) in RCA: 121] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- R C Gallo
- Institute of Human Virology, University of Maryland Biotechnology Institute, University of Maryland, 725 West Lombard Street, Baltimore, MD 21201, USA
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215
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Rana TM, Jeang KT. Biochemical and functional interactions between HIV-1 Tat protein and TAR RNA. Arch Biochem Biophys 1999; 365:175-85. [PMID: 10328810 DOI: 10.1006/abbi.1999.1206] [Citation(s) in RCA: 137] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
HIV-1 trans-activator of transcription (Tat) is an unusual transcriptional activator in being an RNA-binding protein rather than a DNA-binding protein. Recent findings have greatly advanced our understanding of the transcriptional function(s) of this protein. Here we review how Tat interacts with trans-activation responsive RNA and how this interaction contributes to transcription. We discuss the biological implications of recent studies showing an association of Tat with cellular kinases(s) and protein acetylases. Evidence for nontranscriptional activities of the Tat protein is also summarized.
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Affiliation(s)
- T M Rana
- Department of Pharmacology, Robert Wood Johnson (Rutgers) Medical School, 675 Hoes Lane, Piscataway, New Jersey, 08854, USA
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216
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Del Sorbo L, DeMartino A, Biancone L, Bussolati B, Conaldi PG, Toniolo A, Camussi G. The synthesis of platelet-activating factor modulates chemotaxis of monocytes induced by HIV-1 Tat. Eur J Immunol 1999; 29:1513-21. [PMID: 10359105 DOI: 10.1002/(sici)1521-4141(199905)29:05<1513::aid-immu1513>3.0.co;2-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
HIV-1 Tat protein has been shown to induce chemotaxis and recruitment of monocytes. In the present study, we evaluated whether HIV-1 Tat protein was able to induce the synthesis of platelet-activating factor (PAF), which is a potent mediator of cell motility, and whether the synthesis of PAF was instrumental in triggering Tat-induced monocyte chemotaxis. The results obtained indicate that Tat, but not gp120 and gp41, induced a time-dependent synthesis of PAF from monocytes at concentration as low as 0.1 ng/ml. As inferred by the inhibitory effect of anti-Flt-1 antibody and by the desensitization of monocytes following preincubation with vascular endothelial growth factor, the synthesis of PAF by monocytes stimulated with Tat was induced by activation of vascular endothelial growth factor receptor 1. Moreover, the Tat-induced chemotaxis of monocytes was abrogated both by WEB 2170 and by CV 3988, two chemically unrelated PAF receptor antagonists, suggesting that the synthesized PAF modulates the chemotactic response of monocytes to Tat. In conclusion, the results of the present study indicate that Tat-induced PAF synthesis plays a critical role in triggering the events involved in the migratory response of monocytes.
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Affiliation(s)
- L Del Sorbo
- Dipartimento di Medicina Interna, Università di Torino, Italy
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