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Biomedical subjects

V Vonka

Publications and source records attributed to V Vonka.

At least 127 records · Page 7Linked to original sources
PubMed1982

[Contribution to the true non-African Burkitt's lymphoma (author's transl)].

It is reported on a 6-year-old Middle European boy suffering from a nasopharynx tumor with involvement of a submandibular lymph node. The tumor was classified by morphologic, serologic and virologic data as a true or Epstein-Barr virus-associated Burkitt's lymphoma, resp., which has been, up to now, seldom seen outside Africa. The patient died 3 months after diagnosis. Autopsy has shown tumor involvement of nasopharynx and soft tissues in the left neck region, several lymph nodes, kidneys, liver, spleen, and bone marrow. Cytologic, light and electron microscopic data are reported and the structural change of the tumor is referred to.

Autopsy↗
PubMed1982

Subviral herpes simplex vaccine.

An experimental split herpes simplex type 1 (HSV-1) vaccine, virtually free of virus DNA, was prepared from a Nonidet P-40--extract of HSV-1 infected human diploid cells. For determining the contents of neutralizing antigens in these preparations a chromium release inhibition test (CRIT) was developed. The vaccine was gradually shown to be capable of inducing neutralization antibody formation in various animals and conferring protection against intraperitoneal challenge with either type 1 or type 2 viruses in mice. Its administration to mice also markedly restricted the establishment of latent infection following the virus infection. There was an excellent correlation between the immunogenicity of the vaccine and the content of neutralizing antigens as determined by CRIT.

Animals↗
PubMed1982

[Influenza virus penetration into the cells of a continuous dog-kidney line].

The penetration of the influenza virus (WSN) into MDCK cells and its intracellular fate was studied using electron microscopy of ultrathin sections of infected cells at early steps of infection, and biochemical analysis of intracellular subviral components. In electron micrographs, the virus particles absorbed on the cells and located inside phagosomes were detected. In both the cases, the fusion of the virus with cell envelopes was distinctly seen. The fusion took place with incubation at 37 degrees C and 4 degrees C, thus suggesting a non-enzymatic mechanism. The inner virus component released into the cytosol after fusion represented virus cores, i. e. ribonucleoproteins (the final products of uncoating) surrounded by the inner protein membrane consisting of matrix (M) protein. The cores were accumulated in perinuclear cytoplasm of infected cells and were most probably intermediates in virus uncoating.

Adsorption↗
PubMed1981

Presence of Epstein-Barr virus DNA in tonsillar tissues.

Sera from 48 tonsillar carcinoma (TC) patients, 48 matched controls and 16 recurrent exudative tonsillitis (RET) patients were examined for the presence of Epstein-Barr virus (EBV) associated nuclear antigen (EBNA), early antigen (EA) and virus capsid antigen (VCA). Higher prevalence and significantly higher antibody titres against all three EBV-associated antigens were observed in TC patients in comparison with controls and RET patients. Patients suffering from anaplastic TC had higher titres of antibodies against VCA and EA than TC patients with other histological diagnoses. Five out of 11 TC biopsies obtained from 9 patients were positive for EBV DNA at levels of 0.17, 4 to 5, 15 to 18 and in two cases 3 EBV genome equivalents per cellular genome. Among 16 RET patients, 4 were found positive at levels not exceeding 2.17 EBV genome equivalents per cellular genome. Higher titres of antibody against all EBV antigens were found in TC and RET patients with EBV DNA-positive tonsillar tissue than in those with EBV DNA-negative tonsillar tissue.

Adult↗
PubMed1980

[Demonstration of Epstein-Barr virus genome in european Burkitt lymphoma (author's transl)].

A 6-year-old European boy with a tumour in the head and neck region died 86 days after the first occurrence of symptoms despite chemo- and radiotherapy. An epipharyngeal biopsy at the beginning of the disease and a cytological investigation of biopsy and autopsy material showed non-Hodgkin lymphoma with a high degree of malignancy of the Burkitt type. High antibody titres against Epstein-Barr virus (EBV)-specific virus capsid antigen, nuclear antigen and the R component of the EBV-early-antigen-complex as well as the approximately 27 EBV genome equivalents per tumour cell, demonstrated by DNA-DNA hybridisation, characterised the tumour as true Burkitt lymphoma which is observed extremely seldom outside Africa.

Antigens, Viral↗
PubMed1980

Immunogenicity of subviral herpes simplex virus type 1 preparation: protection of mice against intradermal challenge with type 1 and type 2 viruses.

An intradermal assay system for herpes simplex virus in the infected pinna (external ear) of mice was utilized for examining the immunogenicity of an experimental subviral herpes simplex type 1 virus vaccine. The administration of one dose of vaccine with adjuvant did not prevent the appearance of erythema; however, it markedly reduced the severity skin lesions induced by either type 1 or type 2 virus. In addition, neurological complications frequently seen in control mice were never observed in immunized animals. In subsequent experiments the virus content in the pinna tissues of immunized and control animals was determined at different intervals after infection. The results suggest that the immunization had resulted in an acceleration of the clearance of infectious virus from the tissues.

Adjuvants, Immunologic↗
PubMed1980

Interaction of EBNA with anti-EBNA antibody and DNA.

Binding of Epstein-Barr-virus-determined nuclear antigen (EBNA) to acid-fixed nuclei could be prevented by exposing EBNA to anti-EBNA antibodies. While EBNA is eluted from acid-fixed nuclei by 0.4 M NaCl, it was not eluted even by 1.5 M NaCl if EBNA bound to acid-fixed nuclei had been exposed to anti-EBNA antibody. In this case the reaction was abolished, and EBNA was at least partially eluted by 0.2 M glycine buffer, pH 2.8, or by 3 M NaSCN. EBNA not exposed to antibody was completely eluted from acid-fixed nuclei by treatment with a solution containing 200 microgram of DNA per 1 ml of isotonic buffer, pH 6.5; however, after treatment with antibody, EBNA was not eluted by DNA.

Antibodies, Viral↗
PubMed1980

Binding of SV40 tumour antigen and Epstein-Barr-virus nuclear antigen to isolated acid-fixed nuclei.

SV40 tumour antigen (TA) bound to methanol-acetic-acid-fixed interphase nuclei and metaphase chromosomes. This reaction was visualized by the anti-complement immunofluorescence test. The reaction was negative when the nuclei had been treated with deoxyribonuclease prior to the addition of antigen, or when TA-antibody negative serum had been used. In parallel tests TA and Epstein-Barr virus nuclear antigen were examined. Both the binding patterns and the optimum conditions for the reaction were similar.

Animals↗
PubMed1980

Restriction of latent herpes virus infection in rabbits immunized with subviral herpes simplex virus vaccine.

The ability of an experimental herpes simplex virus type 1 (HSV) vaccine to influence the establishment of latent infection was examined. The virion-free vaccine was prepared from HSV 1-infected LEP cells by extraction with Nonidet P 40. Albino rabbits were immunized with three doses of the subviral vaccine (strain KOS) and challenged with 10(5) PFU of HSV 1 (Kupka strain) into the right scarified cornea. Non-immune controls and rabbits immunized with formalin-inactivated virion vaccine (strain KOS) were infected in a similar way. At intervals from 53 to 164 days p. i., the animals were killed and fragments of both trigeminal ganglia were kept separately in culture for 10 days. In 18 out of 22 immunized animals (81.8%), latency was established in the homolateral Gasserian ganglion. The proportion of HSV-yielding fragments, was considerably higher in ganglia from non-immune animals (42.6%) as compared to those from ganglia of rabbits immunized with the subviral vaccine (5.4%) or with the whole virion vaccine (14.6%). The immunity resulting from previous vaccination restricted about 5 times the number of ganglion cells, which become virus carriers.

Animals↗
PubMed1980

Immunogenicity of subviral herpes simplex virus preparations: protection of mice against intraperitoneal infection with live virus.

The capability of crude antigen extracts from herpes simplex virus type 1-infected human diploid cells (AM) to induce protection against intraperitoneal challenge with homotypic but heterologous virus in mice was investigated. The administration of repeated doses of AM without adjuvant failed to confer significant protection. But one relatively small dose of AM with complete Freund's adjuvant resulted in a protective effect. A good correlation was observed between the protective activity of AM preparations and the content of neutralizing antigens as determined by the chromium release-inhibition test. Protection was observed even in animals which were free of neutralizing antibody at the time of challenge. The administration of one dose of cyclophosphamide (120 mg/kg body weight) on day 7 or day 14 after immunization depressed antibody formation but had no effect on the rate of protection. These findings seem to corroborate previous observations on the important role of cell-mediated immunity in protection against herpes simplex.

Animals↗
PubMed1979

Immunogenicity of subviral herpes simplex virus preparations. I. Formation of neutralizing antibodies in different animal species after administration of herpes simplex virus solubilized antigens.

Production of neutralizing antibodies was followed in guinea pigs, rabbits, hamsters and mice immunized with crude antigen extracts (AM) from human diploid cells infected with herpes simplex virus type 1. The AM induced relatively high levels of neutralizing antibodies in all four species. The antibodies were predominantly complement-requiring and remained so even after administration of repeated AM doses. With the strains used, the antibody response was predominantly type specific and, surprisingly, the type specificity of sera usually increased after administration of repeated doses of AM. Guinea pigs seemed to be the best responsive animal species. They developed the highest levels of antibodies and complement-nonrequiring antibodies were seen in them earlier than in the other animal species. The dose-response experiments carried out in guinea pigs indicated that after a single dose administration the ratio between complement-requiring and complement-nonrequiring antibodies was dependent on the amount of antigen administered. When AM was given without adjuvant less efficient antibody production wws observed than after the administration of the same amount of antigen with adjuvant.

Animals↗
PubMed1979

Replication of two influenza virus strains and a recombinant in HEF and LEP cells.

The replication of influenza viruses A/NWS-D, A/WS-MK and their r12 recombinant in human embryo fibroblast (HEF) and human diploid fibroblast (LEP) cell lines was studied. In HEF cells virus NWS-D and recombinant r12 induced synthesis of virus-specific macromolecules and produced infectious virions; virus WS-MK induced synthesis of virus complementary RNA (cRNA), virion RNA (vRNA), protein, RNP and non-infectious virions, but haemagglutinin cleavage was impaired and the virions formed contained uncleaved haemagglutinin. In LEP cells, infectious virions were formed only by virus NWS-D; viruses WS-MK and r12 induced synthesis of virus cRNA, vRNA, proteins and RNP; virus r12 had the haemagglutinin cleaved, whereas in virus WS-MK this process was impaired; neither virus WS-MK nor r12 was capable of forming virions. Analysis of the recombinant r12 genome showed that it had only inherited a single gene from NWS-D, the one coding for neuraminidase, having inherited all others (P1, P2, P3, HA, NP, M, NS) from WS-MK. The data obtained suggested that the inability of virus WS-MK to form infectious virions in HEF cells is due to the character of its neuraminidase, which is incapable of participating in haemagglutinin cleavage. The deficient reproduction of this virus in the other host-cell system (LEP) is apparently associated with some characteristics of another protein (other proteins) of this virus.

Animals↗
PubMed1979

Blocking of acid-fixed nuclear binding of Epstein-Barr virus nuclear antigen (EBNA) by different DNA species.

Treatment of Epstein-Barr virus-determined nuclear antigen (EBNA) with DNA resulted in blocking of its ability to convert acid-fixed EBNA-negative cell nuclei to an EBNA-positive form. Epstein-Barr virus (EBV) DNA, herpes simplex virus type 2 (HSV-2) DNA and DNA isolated from three lymphoblastoid cell lines differed in their potency to block this reaction. EBV DNA was found to be about three times more effective than cellular DNAs in abolishing the ability of DNA-cellulose-purified EBNA to convert acid-fixed nuclei to the EBNA-positive form; the effect of HSV-2 DNA was of intermediate character. No difference was found between the blocking potency of DNAs isolated from EBV-genome-negative Ramos cells and EBV-genome-positive Raji and P3HR-1 cells.

Antigens, Viral↗