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Biomedical subjects

J Roubal

Publications and source records attributed to J Roubal.

At least 19 recordsLinked to original sources
PubMed1991

Mapping of serologically relevant regions of human cytomegalovirus phosphoprotein pp150 using synthetic peptides.

The entire amino acid sequence of human cytomegalo-virus (HCMV) 150K matrix phosphoprotein (pp150), consisting of 1048 amino acid residues, was divided into 95 overlapping 20 amino acid peptides which were synthesized on polyethylene rods. The rods were subjected to ELISA with pooled anti-HCMV-positive and anti-HCMV-negative sera. Four peptides recognized by the anti-HCMV-positive pool only were synthesized by the solid-phase method and their reactivity in a conventional ELISA, using a panel of 14 individual anti-HCMV-negative and 20 anti-HCMV-positive antisera, was evaluated; three peptides were found to be specifically reactive. Results obtained with one of these peptides (residues 595 to 614) in ELISA showed a good correlation with those obtained using a routinely performed complement fixation test.

Amino Acid Sequence↗
PubMed1990

A general procedure for evaluation of immunological relevance of synthetic peptides: peptides synthesized on paper in enzyme-linked immunosorbent assay.

Multiple continuous-flow solid-phase peptide synthesis has been adapted for synthesis of peptides on a cellulose carrier (Whatman 3MM paper). Paper-bound synthetic peptides that represent antigenic determinants of particular proteins detected antibodies against the respective proteins in an enzyme-linked immunosorbent assay. The method is applied to the synthesis, and use in site-directed serology, of four peptides derived from the gp41 glycoprotein of HIV, the Epstein-Barr virus-determined nuclear antigen-1 and VCA proteins of the Epstein-Barr virus, and the early region of human papillomavirus type 11.

Amino Acid Sequence↗
PubMed1990

Antibody against synthetic peptide derived from Epstein-Barr virus-determined nuclear antigen 1 (EBNA-1) in child non-Hodgkin's lymphoma.

Antibody reactivity against a synthetic peptide derived from Epstein-Barr virus nuclear antigen 1 (EBNA-1) was determined in 56 cases of child non-Hodgkin's lymphoma and 31 controls. The patients were divided into subgroups based on tumour location and histology and the antibody responses in the various groups were compared. A significant increase in both IgG and IgM antipeptide titres was detected in patients with tumours localized in the abdomen. High IgG titres were also noted in Burkitt-type, lymphoblastic, and centroblastic lymphomas. On the other hand, low or nil IgG titres were found in unclassified malignant lymphomas, in four cases of centroblastic-centrocytic lymphoma and in lymphomas located in the mediastinum. Surprisingly, the occurrence of antipeptide IgM antibody was highest in those tumours, where IgG titres were low, i.e. in subjects with mediastinal tumours and in unclassified malignant lymphomas. However, with the exception of tumours localized in the abdomen and unclassified tumours, the IgM titres in positive individuals were low and comparable with titres found in a part of healthy controls.

Abdominal Neoplasms↗
PubMed1988

Antibody response to Epstein-Barr virus antigens in patients with chronic viral infection.

We tested antibody titres against Epstein-Barr virus (EBV) antigens in patients suffering from chronic viral disease and compared them with those determined in sex- and age-matched healthy controls. Patient sera showed signs of active EBV infection [antibodies against early antigen (EA) and/or viral capsid antigen (VCA) in the IgM or IgA classes] significantly more frequently than the control group. Correspondingly, geometric mean titres (GMT) of antibodies against all viral antigens were elevated in the patients. The strongest association with EBV was observed in patients whose clinical symptoms closely resembled infectious mononucleosis: 92% of the subjects in this subgroup possessed anti-EA and 41 and 25% had IgM and IgA anti-VCA antibody, respectively. In patients with signs of lymphoproliferation only and in those suffering from frequent respiratory infections the association with EBV was less marked but still significant. Patients with transient defects in humoral and cellular immunity mounted higher titres against VCA in the IgG class than those without immune defects.

Adult↗
PubMed1988

Induction of Epstein-Barr virus antigens by hydroxyurea.

Treatment of the Epstein-Barr virus (EBV)-transformed, virus-producer P3HR-1 cell line with hydroxyurea (HU) resulted in increased synthesis of the EBV-specific early antigen (EA) and viral capsid antigen (VCA). The induction was noted already at a 200 mumol/l and reached plateau at a 1500 mumol/l HU concentration. At plateau concentration, the percentage of cells expressing EA and VCA was about 5 times higher than in the absence of the drug.

Antigens, Viral↗
PubMed1988

Epstein-Barr virus (EBV) antibodies in children with non-Hodgkin's lymphomas.

Antibody titres against Epstein-Barr virus (EBV) antigens in children suffering from non-Hodgkin's lymphoma (NHL) were determined. IgG antibody titres against the viral capsid antigen (VCA) and early antigen (EA) exceeded those found in healthy control subjects. On the other hand, antibody titres against EBV-determined nuclear antigen (EBNA complex) were generally lower than in the control group. The most striking phenomenon observed in the patient group was the frequent activation of latent virus infection as revealed by the periodical appearance of anti-EA and IgM class anti-VCA antibodies. Antibody titres against EBV antigens were generally lower among patients with progressing disease than in those with a more favourable course of the illness. The closest relation to EBV based on serological findings, was detected in lymphoblastic lymphomas of Burkitt-type histology, poorly differentiated lymphocytic lymphomas, and in lymphomas localized in the abdomen. The question whether EBV might be involved in a certain proportion of the cases examined is discussed and further approaches to elucidate this problem are suggested.

Adolescent↗
PubMed1988

Unchanged expression of Epstein-Barr virus-determined nuclear antigen-1 in productive virus cycle.

The level of the Epstein-Barr virus (EBV)-determined nuclear antigen (EBNA-1) encoded by the Bam HI-K fragment of EBV DNA remained unchanged in P3HR-1 cells after induction of the productive cycle of virus replication by sodium-n-butyrate and 12-o-tetradecanoylphorbol-13-acetate (TPA). This was shown by the same capacity of cell-free extracts from untreated and treated P3HR-1 cells to absorb anti-EBNA-1 antibody from a known human serum.

Antigens, Viral↗
PubMed1988

Effects of cis-dichloro-diammine-platinum (II) (cis-DDP) on Epstein-Barr virus induction and cell differentiation.

Morphological changes were induced by cis-dichlorodiammine platinum (II) (cis-DDP) in two Epstein-Barr virus (EBV) transformed cell lines: the productive P3HR-1 and the nonproductive Raji cell line. In P3HR-1 cells cis-DDP induced synthesis of viral antigens, viral particles and morphological changes characteristic for virus replication. In Raji cells, the virus replicative cycle was not induced and virus-specific morphological changes were limited to the sporadic appereance of some very early alterations in cell morphology. However, in Raji cells, but not in P3HR-1 cells, up to 20 per cent of the cell population exhibited differentiation-related changes towards plasma cell morphology. The most advances stage of cell differentiation detected was classified as plasmablast. Cis-DDP also induced some changes associated with the cytostatic effect of the drug. In the treated cell population cytokinesis was inhibited and frequently multinuclear cells appeared; moreover, extensive degenerative changes were observed.

Antigens, Viral↗
PubMed1987

Chemically purified serum factor can induce both Epstein-Barr virus antigen synthesis and cell differentiation.

The effects of purified Epstein-Barr virus-inducing serum factor (EIF) on the lymphoblastoid cell line Raji latently infected with Epstein-Barr virus were studied. Activated serum factor was capable of both: cooperating with n-butyrate and/or TPA in inducing synthesis of EBV antigens and triggering cell differentiation towards plasma cell as determined by electron microscopy. It seems therefore that the same serum component was involved in the induction of both phenomena.

Antigens, Viral↗
PubMed1985

Effects of activated serum factor on the induction of Epstein-Barr virus antigens and cell differentiation.

n-Butyrate and 12-0-tetradecanoylphorbol-13-acetate (TPA) have been shown to be potent inducers of Epstein-Barr virus (EBV) antigen synthesis (10, 18) and cell differentiation (1,2). Activated serum factor (SF) has also been reported to induce virus antigen synthesis and moreover it is capable of cooperative action with other inducers (5). We have demonstrated with an EBV-carrying lymphoma cell line (Raji) that activated SF can also induce the appearance of some cellular alterations, specific for early steps of the productive virus cycle in a low proportion of cells. In addition cell differentiation towards plasma cell was noted in about 8 per cent of SF-treated cells. It was confirmed that activated SF enhances the induction of virus antigens by n-butyrate or TPA as detected by the immunofluorescence technique. It was shown that it also potentiates the development of virus-induced changes in cellular morphology and the cell differentiation induced by these drugs. This effect was more pronounced in combination with TPA than with butyrate. Possible relationships between cell differentiation and virus-antigen expression are discussed.

Antigens, Viral↗
PubMed1985

Effect of n-butyrate on transformation of human lymphocytes by Epstein-Barr virus.

3 mM n-butyrate, which effectively induces synthesis of Epstein-Barr virus (EBV) antigens in the producer P3HR-1 cell line, inhibited the transformation of umbilical cord blood lymphocytes by EBV. The drug inhibited both EBNA synthesis and stimulation of host cell DNA synthesis by strain B95-8. This effect was less pronounced at lower concentrations, but even at 0.1 mM (which did not affect DNA synthesis in EBNA and stimulation of host cell DNA synthesis in EBV-infected lymphocytes were delayed.

Butyrates↗
PubMed1985

Effect of n-butyrate on superinfection of Raji lymphoblastoid cell line by Epstein-Barr virus.

The effect of n-butyrate on superinfectability of virus-nonproducer Raji cells by the P3HR-1 strain of Epstein-Barr virus (EBV) was investigated. n-Butyrate is known to be a potent inducer of virus antigen synthesis in virus-producer cell lines and of cell differentiation in virus nonproducers. The drug inhibited the growth of Raji cells but did not interfere markedly with cell viability. It induced a low rate of early antigen (EA) synthesis in about 1-2% of noninfected Raji cells. While the number of superinfectable cells remained relatively constant after treatment with butyrate, an increase in antigen positivity was noted in untreated cells. This relative decrease in sensitivity to superinfection in butyrate-treated Raji cells was more pronounced in cultures that had been treated with the drug for 48 or 72 hr as compared to those treated for 24 hr. A blocking of the treated cells in the certain cell-cycle phase and their drug-induced differentiation towards plasma cells might have been involved in the phenomenon described.

Antigens, Viral↗
PubMed1984

Effects of n-butyrate and phorbol ester (TPA) on induction of Epstein-Barr virus antigens and cell differentiation.

N-Butyrate, an effective inducer of synthesis of Epstein-Barr virus (EBV) antigens in virus-producer P3HR-1 cells, has recently been shown (2) to induce morphological differentiation towards plasma cell in nonproducer Raji cells. The effects of n-butyrate and 12-O-tetradecanoylphorbol-13-acetate (TPA) on both EBV-antigen induction and cell differentiation in two virus-nonproducer lymphoblastoid cell lines, Raji and NC37, were now studied. The following observations were made (1). On its own either drug induced 1-2 per cent of cells to EBV-early-antigen positivity in both lines; their mixture induced 35 and 15 per cent positive cells in Raji and NC37 respectively (2). In Raji, n-butyrate induced about 80 per cent of cells to differentiate to plasmablast or plasma cell morphology, whereas TPA only induced the early stages of differentiation in 8 per cent of cells; a mixture of both inducers produced a similar effect as TPA alone. The addition of TPA alone or butyrate-TPA mixture led to some cellular alterations resembling virus-specific changes in virus-producer cell lines. In NC37, either drug alone or their mixture drove 13 per cent of cells to differentiate into plasmablasts or earlier stages of differentiation. In the presence of TPA protrusions and "loops" were seen on cell surfaces. Evidently, the stage of differentiation at which B-lymphoblastoid cell lines have been arrested can be changed in vitro. However, cell-line dependent and inducer-dependent differences in the differentiation response were apparent.

Antigens, Viral↗
PubMed1983

Functional complementation between Epstein-Barr virus and herpesvirus papio.

The possibility of complementation between herpesvirus papio (HVP) and Epstein-Barr virus (EBV) was investigated. Strain 594S-F9 of HVP, unlike strain P3HR-1 of EBV, is not capable of inducing virus antigen synthesis in the EBV genome-carrying, nonproducer lymphoma cell line Raji. The effects of dual infection with these viruses were studied. With untreated viruses, the percentage of cells positive for viral antigens was equal to or slightly less than that in cultures infected with P3HR-1 virus only. However, if UV-irradiated P3HR-1 virus was employed in the dual infection, the relative number of virus antigen-positive cells was enhanced over cultures infected with P3HR-1 virus alone. These results suggest functional complementation between EBV and HVP.

Animals↗
PubMed1983

Induction of Epstein-Barr virus antigens and DNA-polymerase activities in P3HR-1 cell line and its subline passaged in the presence of phosphonoformate.

Lymphoblastoid cell line P3PFA was derived from P3HR-1 cells by long-term cultivation in the presence of phosphonoformate (PFA). Spontaneous production of Epstein-Barr virus antigens in PFA-selected subline was markedly reduced in comparison with the original cell line. Induction of early antigen (EA) and viral capsid antigen (VCA) syntheses with 5-iodo-2-deoxyuridine (IUDR), n-butyrate and 12-o-tetradecanoyl phorbol-13-acetate (TPA) was significantly less efficient in P3PFA than P3HR-1 cells. This was most likely associated with reduction in the number of viral genome copies per P3PFA cell that decreased more than one hundred times in comparison with P3HR-1 line. The synthesis of EA in both cell lines was not inhibited in the presence of PFA. On the other hand, PFA inhibited the synthesis of VCA by 95 and 30% in P3HR-1 and P3PFA, respectively. The relative resistance of VCA synthesis to PFA in P3PFA cells was not due to the presence of a drug-resistant virus-specific DNA-polymerase. It is noteworthy that the activity of virus-specific enzyme was markedly reduced, while cellular enzyme activity was significantly enhanced in induced P3PFA cells when compared to P3HR-1 cells treated in the same way.

Antigens, Viral↗
PubMed1983

Immunological properties of lymphoblastoid cell lines (UHKT) - 1, 2, 3, 4, 5, 6) established from cases of human leukemias.

Immunological characteristics of stabilized cell lines (UHKT-1, 2, 3, 4, 5, 6) established from cells of peripheral blood of patients with leukemia were studied. Attention was focussed on the analysis of various membrane markers (e. g. T, Ia-like, antigens, membrane immunoglobulin, receptors for sheep erythrocytes, for IgG-Fc fragment, for the third component of the complement and expression of beta-2 microglobulin). The cells of these lines were also tested for the presence of Epstein-Barr virus-determined nuclear antigen (EBNA) and other EBV antigens. Chromosomal analysis was performed repeatedly. The UHKT cell lines were compared to the standard cell lines obtained from other laboratories. The results showed that rabbit antiB xenosera revealed Ia- antigen on the cells of B cell lines. The determination of T and B cell types using rosette test was less convincing in some lines.

Antigens, Surface↗
PubMed1982

Effects of n-butyrate on Epstein-Barr virus-carrying lymphoma lines.

n-Butyrate has been shown to induce Epstein-Barr virus (EBV) antigen synthesis in certain EBV-carrying lymphoma lines (Luka et al., 1979). We have studied the effect of n-butyrate on two EBV-positive Burkitt lymphoma lines by immuno-fluorescence and electron microscopy. In the producer line P3HR-1, the drug induced not only early antigen (EA) and virus capsid antigen (VCA) synthesis, as shown before, but also increased the number of cells containing virus particles. The transition from VCA expression to the formation of virus particles was much more effective in treated cells than in EBV antigen-producing cells of the same line. The productive cycle was associated with the development of characteristic morphological changes. In the non-producer Raji cells, n-butyrate induced EA in only a minor fraction of the cells. There were, however, clear signs of differentiation in the direction of plasma cells. Two days after the addition of n-butyrate 80% of the Raji cells could be classified as plasmablasts. After 72 h, 20% of the cells appeared as typical plasma cells.

Antigens, Viral↗