Spectrum of biological properties of human immunodeficiency virus (HIV-1) isolates

Cloyd, Miles W.; Moore, Barbara

doi:10.1016/0042-6822(90)90059-z

Cited by 99 publications

(50 citation statements)

References 49 publications

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“…Further evidence of this intracellular control is provided by biological studies showing variations in replication of HIV-1 strains in different cell lines, macrophages, and PBMCs from various donors (Levy ef al., 1985a;Castro etal., 1990;Cloyd and Moore, 1990;von Briesen etal., 1990;Olafsson etal., 1991). The virus furthermore specifies a protein called the transactivator (Tat), which prevents RNA polymerase II from falling off during transcription (Peterlin etal., 1986;Marciniak etal., 1990a).…”

Section: Viral Gene Expressionmentioning

confidence: 99%

Review

1996

Biological Chemistry Hoppe-Seyler

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Proteolytic enzymes have many physiological functions in plants, bacteria, viruses, protozoa and mammals. They play a role in processes such as food digestion, complement activation or blood coagulation. The action of proteolytic enzymes is biologically controlled by proteinase inhibitors and increasing attention is being paid to the physiological significance of these natural inhibitors in pathological processes. The reason for this growing interest is that uncontrolled proteolysis can lead to irreversible damage e.g. in chronic inflammation or tumor metastasis. This review focusses on the possible role of the cystatins, natural and specific inhibitors of the cysteine proteinases, in pathological processes. Key words: Cystatins / Cysteine proteinases / Inflammation / Inhibitors / Pathological processes. Cysteine ProteinasesCysteine Proteinases, synonymous with thiol proteinases, are small proteins with molecular masses varying from 23 to 24 kDa and with two catalytic residues, Cys25 and His159, which are involved in the hydrolytic reaction. Cysteine proteinases catalyze the hydrolysis of various polypeptide substrates and are most active under reducing and mildly acidic conditions (pH 5 -6.5). They have been detected in and isolated from a large number of biological sources including plants, bacteria, animals and humans. Bacterial cysteine proteinases are produced by Clostridium histolyticum, named clostripain, by hemolytic group A streptococci and by the pathogenic anaerobic Porphyromonas gingivalis, a bacterium associated with periodontitis. Bacterial cysteine proteinases probably play a role in the penetration of normal tissues by the bacteria and in the food digestion. Viral cysteine proteinases from picornaviruses, e.g. the poliovirus and rhinovirus type I, are involved in proteolytic cleavage of precursor proteins for virus replication and for the production of new virus particles. A virus-coded cysteine proteinase is involved in this process (Kay and Dunn, 1990; Körant et a/., 1985;. HIV-I also needs proteolytic processing by cysteine proteinases to regulate the expression of viral proteins (Guy ef a/., 1991). Protozoal cysteine proteinases are produced by a number of protozoan parasites to facilitate host invasion, metabolize host proteins, to degrade the host immune molecules or to use them for intracellular replication. Cysteine proteinases are produced by e.g. Trypanosoma cruzi, the causative agent of American trypanosomiasis or by Leishmania species, causing one of the six major parasitic diseases. Furthermore, human malarial parasites produce a broad scala of proteinases including cysteine proteinase which are involved in erythrocyte invasion and rupture (McKerrow, 1993). Mammalian cysteine proteinases are present in the lysosomes of cells. Lysosomes contain different cysteine proteinases, the most important being the cathepsins B, H, L and S Kirschke, 1981, Barrett et a/., 1988). These cathepsins have common ancestors and are related to papain. Cathepsin B has been detected in every tissue or cel...

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Section: Viral Gene Expressionmentioning

confidence: 99%

Review

1996

Biological Chemistry Hoppe-Seyler

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“…Most often infection leads to rapid c.p.e, with or without syncytium formation and cell death. In other cases, c.p.e, is moderate, with recurrent cytopathic/non-cytopathic periods, or a rather stable equilibrium between uninfected and infected cells exists Cloyd & Moore, 1990). Some infected cells can retain their morphological integrity and growth potential despite usual viral production.…”

Section: Introductionmentioning

confidence: 99%

Extensive C-terminal Deletion in Human Immunodeficiency Virus Type 1 Env Glycoprotein Arising After Long-term Culture of Chronically Infected Cells

Zaides

Yagello²,

Veselovskaya

et al. 1994

Journal of General Virology

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Human immunodeficiency virus type 1 (HIV-1) chronically infected (CI) cell lines were established from HIV-1,~B/LA~-infected MT-4 cells that survived acute infection. The HIV env gene expressed in the two longterm cultured cell lines differed from that of the lines cultured for shorter periods, by coding for a glycoprotein gpl60 that had the C terminus deleted. One long-term cultured cell line, CI-17, was studied in detail. An insertion of a premature stop codon in the env gene caused about 90 % of gpl60 molecules to be truncated (gpl60x), lacking both cytoplasmic and transmembrane domains; these species were secreted into the cell medium, and could form oligomers with other truncated gpl60 molecules as well as with their normal counterparts. CI-17 cells constantly yielded high levels of viral protein and relatively low quantities of infectious virus, without cytopathicity. However, acute infection of fresh MT-4 cells with CI-17-derived virus led to cytopathicity, the rate of which as well as the Env glycoprotein pattern depended on multiplicity: (i) using an infection dose of 10 -4 IDs0/cell, cells died 7 to 8 days post-infection with normal gpl60 synthesis predominating; (ii) with l0 -2 IDs0, gpl60x was produced as early as 48 h postinfection and cell death was delayed. Predominant gpl60x formation occurred again when new CI cell lines were obtained with CI-17-derived virus. Thus, two human immunodeficiency virus variants, a normal and a defective one, are persistently expressed in CI-17 cells. The other long-term cultured CI cell line also expressed gpl60 with a similar (albeit slightly longer) deletion of a C-terminal region in most molecules, but the cell lines that were cultured for shorter periods did not. These results suggest that the emergence of HIV variants with a C-terminal deletion in the Env glycoprotein, which coexist with normal virus, may play a role in maintaining the long-term growth capacity and viability of CI ceils.

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“…Fax j81 75 751 3995. e-mail aishimot!virus.kyoto-u.ac.jp occur even without syncytia formation (Cloyd & Moore, 1990 ;Dedera & Ratner, 1991 ;Koga et al, 1994). HIV envelope glycoproteins (gp120 and gp41) and cell-surface CD4 are involved in syncytia formation (Freed et al, 1991 ;Hussey et al, 1988 ;Lifson et al, 1986).…”

mentioning

confidence: 99%

“…The cytopathic properties of HIV are highly dependent on the HIV isolate, cell type and concentration (m.o.i.) of virus (Cloyd & Moore, 1990 ;Dedera & Ratner, 1991). Detailed analysis of the factors that determine the cytopathic effect (CPE) may provide important information on HIV pathogenicity.…”

mentioning

confidence: 99%