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Biomedical subjects

V Wunderlich

Publications and source records attributed to V Wunderlich.

At least 37 records · Page 2Linked to original sources

[The biological effects of coordination compounds of transitional metals. 6. Effect of 4-methyl-2-aminopyridine-palladium chloride and cis-dichlorodiammine-platinum(II) on retroviruses and the virus-associated RNA polymerase of the influenza virus].

The effect on retroviruses of two transition metal complexes of known antiviral activity, 4-methyl-2-amino-pyridine-palladium-chloride (MAP) and cis-dichloro-diammine-platinum(II) (cis-DDP) has been investigated. The experiments included the evaluation of the action of compounds on virus particle-associated reverse transcriptase in exogenous assays, on virus propagation in persistently infected cell cultures and on virus infectivity in mice. In disrupted viruses and in the absence of excess protein, the reverse transcriptase was inhibited by MAP but not by cis-DDP. The same results were obtained when examining the activity of the virus-associated RNA polymerase of influenza virus A/WSN. Both compounds did not inhibit the replication of retroviruses in cell cultures, except at high dose levels which exerted toxic action on both cells and virus formation. The leukemogenicity of Rauscher murine leukemia virus was strongly inhibited when the virus had been incubated with MAP before inoculation. A similar treatment with cis-DDP did not influence viral leukemogenicity. Despite somewhat different results with both compounds tested, we conclude from the present results that the above mentioned compounds cannot be considered as antiretroviral drugs.

Animals↗

[Immunosuppression by retroviruses in tumors and immune deficiency diseases].

Most retroviruses are immunosuppressive in vitro and in vivo. They are able to enhance virus-induced tumor development and/or to induce acquired immune deficiency syndromes (AIDS) which are characterized by malignant tumors and opportunistic infections. Experimental evidence for the immunosuppressive properties of several type D viruses derived from human cell lines and other retroviruses is presented.

Acquired Immunodeficiency Syndrome↗

[The effect of phenolic polymers on retroviruses].

Phenolic polymers synthesized by enzymatic oxidation of coffeic acid, chlorogenic acid, and gentisinic acid were found to strongly inhibit RNA-dependent DNA polymerase (revertase) of retroviruses. Except of two type C retroviruses inhibition became reversible by the addition of bovine serum albumin to the exogenous revertase test. The phenolic polymers tested did not influence the propagation of retroviruses in the cell culture. The replication of Rauscher leukemia virus in mice was diminished by a short-time preincubation of virus suspension with coffeic acid polymer (KOP). In contrast, the preincubation of a virus-containing serum with KOP increased the leukemogenic effect of the virus. KOP given to mice at a high dose subsequently to virus inoculation resulted in high revertase activities and in an elevation of spleen weights too.

Animals↗

Suppression of human lymphocyte mitogen response by retroviruses of type D. I. Action of highly purified intact and disrupted virus.

The type D retrovirus PMFV, derived from a human cell line, suppresses the in vitro response of human lymphocytes to different T-cell mitogens as well as the mixed lymphocyte reaction. The suppressive effect is virus-specific and the active fraction copurifies with the virus particles. The suppression is produced by both crude and highly purified intact and disrupted virus preparations. However, the suppressive activity of virus disrupted by ether or a detergent is higher as compared with intact virus. The absence of any factors cytotoxic for lymphocytes or lymphoblasts in the suppressive virus preparation is shown by different methods.

Acquired Immunodeficiency Syndrome↗

Suppression of human lymphocyte mitogen response by retroviruses of type D. II. Non-activity of Mason-Pfizer monkey virus versus activity of human cell line derived virus PMFV.

In contrast to the human cell line derived type D retrovirus PMFV, the Mason-Pfizer monkey virus (MPMV) does not suppress the mitogen response of normal human lymphocytes. Both viruses have been propagated on the same cell lines and purified by the same methods. MPMV did not contain a factor able to abolish PMFV-induced suppression of the mitogen response. Neither could MPMV suppress the mitogen response of lymphocytes from rhesus monkeys or baboons. PMFV however inhibited their reactivity.

Animals↗

Teleocidin, a tumour promoter, stimulates synthesis of primate retroviruses in persistently infected human cells.

The naturally occurring tumour promoter teleocidin produces a pronounced but transient enhancement of the synthesis of extracellular viral particles in human cells chronically infected with simian retroviruses of type C (baboon endogenous virus, simian sarcoma virus) or type D (Mason-Pfizer monkey virus) or a human cell line-derived type D isolate (PMF virus), respectively. The retrovirus-stimulating activity of teleocidin is very similar to that previously described for the tumour-promoting phorbol ester TPA in the same cell systems.

Carcinogens↗

Bovine leukemia virus (BLV)--a structural model based on chemical crosslinking studies.

Nearest neighbor relationships between lipid and protein as well as between high-molecular-weight viral RNA and protein were investigated in bovine leukemia virus (BLV) particles using chemical crosslinking reagents. Separation of dimethyl suberimidate (DMS) induced lipid-protein complexes by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the phosphoprotein pp 15 is linked to the lipid bilayer of the virus. By use of diepoxybutan (DEB) as crosslinking reagent p 12 and again pp 15 were found to be linked to the viral RNA. Based on these results and our previous data describing the spatial relationships of major structural proteins within BLV particles, a structural model of BLV is proposed.

Animals↗

Enhancement of primate retrovirus synthesis by tumour promoters.

The tumor promoters 12-O-tetradecanoylphorbol-13-acetate (TPA) and teleocidin were found to be effective in stimulating the synthesis of primate retroviruses in chronically infected human cells. Production of baboon endogenous virus, simian sarcoma virus of woolly monkeys, Mason-Pfizer virus of rhesus monkeys and of a type D isolate from a human cell line was evaluated by assaying particle-associated reverse transcriptase activities in culture fluids of cells grown in the presence or absence of tumour promoters. Both TPA and teleocidin caused a significant but transient increase in virus production, as well as cytomorphological changes in the following infected cell types: human embryonic kidney, Tu 197 human ovarian carcinoma cells, NC 37 human lymphoblastoid line. However, infected A 204 human rhabdomyosarcoma cells were not modified by these promoters. The stimulation of virus production reached its maximum after two to four days, at which time virus production was three to forty times higher than that in controls. The optimal concentration of tumour promoters was 5-10 ng/mL. 12-O-Retinoylphorbol-13-acetate produced a similar but somewhat weaker effect. Control experiments demonstrated that enhancement was specific to those viruses that chronically infected each cell type.

Carcinogens↗

A simple method for purification of retroviruses using polyacrylnitrile.

A simple method has been developed that allows the concentration and partial purification of retroviruses from both small and large volumes of culture fluid in a comparatively short period of time. The method is based on the property of polyacrylnitrile (PAN) to adsorb preferentially nonviral proteins. Retroviruses purified by this procedure exhibit rather high specific reverse transcriptase activities and a good appearance in electron micrographs and protein patterns.

Acrylic Resins↗

Biochemical studies of primate retroviruses.

In the present paper, recent biochemical studies of retroviruses carried out in our laboratory are summarized. Protein compositions, peptide maps of internal structural proteins, neighborhoods of major structural proteins, and serological properties of reverse transcriptases of type D virus isolates from human cells (including Graffi's isolate termed PMFV and also isolates from HeLa- and HEp-2 cells) were compared with those of type D viruses from Old World (Mason-Pfizer virus of rhesus monkeys, langur virus) and New World (squirrel monkey retrovirus) monkeys. The results provide various new informations on, and further demonstrate the diversity of primate type D viruses. Other studies showed that tumor promoting agents (phorbol ester TPA, indole alkaloid teleocidin) are able to considerably increase, in a transient manner, the production of type C and type D primate retroviruses in persistently infected human cells. From experiments demonstrating a disintegrating activity of chelating agents (EDTA, EGTA) and certain psychoactive drugs (including trifluoperazine) on various primate and nonprimate retroviruses it is concluded that divalent cations, probably Ca2+ ions, and possibly also cation-binding proteins are associated with retroviral membranes and that complexing of these components results in loss of viral infectivity.

Alkaloids↗

Chemical crosslinking of major structural proteins within type D retroviruses.

The nearest neighbor relationships of major structural proteins within type D retroviruses (SMRV, MPMV, PMFV) were investigated by crosslinking with the cleavable bifunctional reagent dimethyl dithiobispropionimidate (DTBPI) or by use of 2-iminothiolane (methyl mercaptobutyrimidate, MBI) and subsequent oxidation by hydrogen peroxide. The crosslinked complexes of proteins were analyzed by two-dimensional diagonal polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. In intact virions both crosslinking reagents induced the formation of covalently linked complexes of the internal structural proteins as well as complexes containing the envelope glycoproteins. The following complexes were found for each virus: SMRV: (pp20)2; (p35)2,4,6; (pp20-gp68); MPMV: (p10)2,4,6; (p25)2,4; (p10-p25); (gp20-gp68); (p45-gp68); PMFV: (p10)2; (p25)2; (p10-p25); (p45-gp68). In control experiments without crosslinking reagents no covalently linked complexes were detected.

Cross-Linking Reagents↗

Tumor promoter-stimulated synthesis of Mason-:Pfizer monkey virus.

The tumor promoter 12-0-tetradecanoyl-phorbol-14-acetate (TPA) increases by severalfold the synthesis of Mason-Pfizer monkey virus (MPMV), a type D retrovirus, when the virus is growing in human embryo kidney (HEK) cells. The effect is transient and paralleled by a striking morphological alteration of the cells. The optimal TPA concentration for stimulation is 5 ng. ml-1. Contrary to infected HEK cells, TPA induces at similar concentrations neither stimulation of MPMV synthesis nor altered morphology in persistently MPMV-infected cells of the continuous human tumor cell line A 204.

Animals↗

Disintegration of retroviruses by chelating agents.

Exposure in vitro of various mammalian retroviruses to the chelating agents EDTA or EGTA in millimolar concentrations resulted in partial disintegration of viral membranes as measured by accessibility or even release of reverse transcriptase, an internal viral protein, without any other treatment usually required. Among the viruses responding to chelators were mammalian type C viruses, primate type D viruses and bovine leukemia virus. The effect was dose-dependent. The avian type C virus AMV, however, was found to be not susceptible to the agents. Rauscher mouse leukemia virus treated in vitro with EDTA or EGTA showed reduced infectivity in mice. The results are considered as evidence for some association of divalent cations with membranes of mammalian retroviruses. The disintegrating activity of EGTA suggests that Ca2+ is an integral constituent of viruses but Mg2+ may also be involved. These cations seem to be responsible for maintaining integrity of retroviral membranes which, after chelation of ions, are either disrupted or become permeable for the exogenous template of reverse transcriptase. In addition, the disintegrating activity of trifluoperazine may indicate that a calmodulin-like protein occurs in retroviral membranes.

Avian Myeloblastosis Virus↗

Use of Sepharose bead immunofluorescence assay for comparison of the type D retroviruses MPMV and PMFV.

Mason-Pfizer monkey virus (MPMV) and PMFV, an isolate from a human continuous cell line, were compared by Sepharose bead immunofluorescence assay. According to the results with p27-specific assays the main structural protein of both viruses seems to be identical in the prominent antigenic determinants. Differences were found when comparing the p15s indicating that this viral protein contains type-specific antigenic determinants.

Animals↗