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Biomedical subjects

G Klein

Publications and source records attributed to G Klein.

At least 937 records · Page 52Linked to original sources
PubMed1980

Purification and biochemical characterization of the Epstein-Barr virus-determined nuclear antigen and an associated protein with a 53,000-dalton subunit.

The Epstein-Barr virus-determined nuclear antigen (EBNA) was purified 700-fold to apparent homogeneity from Raji and Namalwa cell extracts by a three-step procedure involving heat treatment, DNA-cellulose chromatography, and hydroxyapatite chromatography. Acid-fixed nuclear binding and complement fixation were used to monitor antigenic specificity. Purified EBNA was also capable of specifically inhibiting the regular anticomplement immunofluorescence reaction for EBNA against Raji target cells. The purified antigen had a molecular weight of 170,000 to 200,000. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis, it yielded a single 48,000-dalton (48K) monomer. An EBNA-associated protein was also purified from the same cell extract. It had a molecular weight of about 200,000 and yielded a single 53K protein band by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The same protein was also found in Epstein-Barr virus negative B-cell lymphoma lines. The two types of protein were characterized by amino acid composition and peptide mapping. The results showed that the 53K and 48K protein components have no long regions in common; this excludes that the smaller product arises by breakdown of the larger product. Residue distributions were different, but an excess of hydrophilic residues was found in both proteins, suggesting a certain overall similarity in properties. 53K components from different cell lines appeared to differ somewhat. Epstein-Barr virus-positive lines carry two 53K components, one of which may be a slightly modified 53K product. Immunocomplexing assay showed that the 48K, but not the 53K, protein carries EBNA specificity. In mixtures, the 53K protein is co-precipitated with the 48K protein. The data suggest that EBNA may form a complex with the 53K proten within the cell.

Antigens, Viral↗
PubMed1980

Interaction of Herpesvirus ateles and Hepesvirus saimiri with primate lymphocytes. I. Selective adsorption of virus by lymphoid cells.

A semiquantitative infectious bioassay, described by Sairenji and Hinuma for the measurement of Epstein-Barr virus (EBV) receptors, was adapted to study the adsorption of the lymphotropic New World herpesvirus ateles (HVA) to established lymphoid lines and lymphocytes of human versus marmoset origin. All marmoset T-cell lines [HVA- or HVS (herpesvirus saimiri)-carrying] had a high adsorbing capacity. EBV-carrying marmoset or human B-cell lines, one EBV-negative human B-lymphoma line, and one human myeloid leukemia-derived line failed to adsorb detectable virus. Two human T-cell derived cell lines of acute lymphatic leukemia origin showed moderate but significant adsorption, and the same was true for unfractionated marmoset lymphocytes. Human peripheral blood did not adsorb, before or after fractionation, whereas normal human thymocytes showed moderate but significant adsorption. It is concluded that HVA receptors are present on human T cells, probably belonging to certain subclasses.

Adsorption↗
PubMed1980

Effect of mitomycin C and hydroxyurea on the expression of the Epstein-Barr virus cycle following P3HR-1 superinfection.

Epstein-Barr virus (EBV) DNA synthesis following EBV P3HR-1 superinfection of the Burkitt lymphoma cell line, Daudi, is refractory to mitomycin C and hydroxyurea at concentrations which inhibit cell DNA synthesis to greater than 98% of control values. Further, neither mitomycin C nor hydroxyurea inhibit virus antigen synthesis following P3HR-1 superinfection.

Antigens, Viral↗
PubMed1980

Restriction of C-type viral antigen in H-2/Fv-1 syngeneic mouse somatic cell hybrids.

Somatic cell hybrids between an AKR lymphoma or a C3H sarcoma and H-2, Fv-1 syngeneic CBA sarcoma or carcinoma have been examined for expression of the structural components of murine leukemia virus (MuLV) by radioimmunoassay and complement-dependent cytotoxicity assay. Parental AKR and C3H cells contained high concentrations of MuLV core protein p30 in their cell extracts and showed high sensitivity to anti-MuLVgp70 and p30 sera. In contrast, CBA cells expressed little detectable p30 in the extracts, were much less sensitive to anti-gp70 serum, and were almost insensitive to anti-p30 serum. The hybrids between the AKR or C3H cells and CBA cells had a decreased amount of p30 in the extracts and were almost resistant to cytotoxicity by anti-p30 serum, although they maintained high sensitivity to anti-gp70 serum. These findings suggest that the CBA genotype suppresses the production and cell-surface expression of p30 antigen of AKR and C3H endogenous C-type viruses. The suppressive gene is not Fv-1n.

Animals↗
PubMed1980

Hybridization of a myeloid leukemia-derived human cell line (K562) with a human Burkitt's lymphoma line (P3HR-1).

The myeloid leukemia-derived Epstein-Barr virus (EBV)-negative human lymphoid cell line K562 was successfully hybridized with the EBV-carrying Burkitt's lymphoma line P3HR-1. Authenticity of the hybrid PUTKO-1 was established by chromosome and isoenzyme studies. A virtually complete hybrid PUTKO-1 carried the EBV genome derived from the lymphoma parent. It averaged 26 EBV DNA copies per cell and was 100% positive for Epstein-Barr virus-associated nuclear antigen (EBNA). In most respects, the hybrid resembled the K562 parent: It had a high Fc receptor concentration, high sensitivity to natural killer cells, absence of EBV C3 receptors, and deficiency of membrane-associated beta 2-microglobulin (beta 2M) and HLA, in parallel with intracellular synthesis and secretion of beta 2M to the medium. Unlike the P3HR-1 parent, the hybrid was completely nonpermissive for antigens of the EBV cycle, early antigen, and viral capsid antigen. None of the 3 inducing agents, 5-lodo-2'-deoxyuridine, 12-O-tetradecanoyl-phorbol 13-acetate, or sodium butyrate, caused any viral antigen synthesis in PUTKO-1 in contrast to the good inducibility of the parental P3HR-1 subline. Thus the myeloid parent restricted expression of EBV antigens except EBNA. This exception further supports the concept that EBNA is an autonomous function of the viral genome, independent of host cell control that regulates expression of antigens related to the viral cycle. On the contrary, extinction of viral antigens in this hybrid between 2 cell lineages supports our previous concept that the ability to produce viral antigens is similar to a differentiated B-cell property.

Antigens, Surface↗
PubMed1980

EBV-transformation of surface IgA-positive human lymphocytes.

Surface IgA-positive human lymphocytes were selected, separated, and immortalized with Epstein-Barr virus (EBV). Selection was carried out by rosetting the cells with ox erythrocytes, coated with rabbit anti-human IgA immunoglobulin, followed by separation on Ficoll-Isopaque. Stable monoclonal lines were established by cloning in agarose. This shows that EBV-transformation is not restricted to the IgM-positive B cell category but can be extended to minority classes of B lymphocytes. The method provides the means to establish other minority categories as continuous lines, depending on the efficiency of the preselection procedure.

Animals↗
PubMed1980

Nonrandom chromosomal changes in thy-1-positive and thy-1-negative lymphomas induced by 7,12-dimethylbenzanthracene in SJL mice.

Leukemias were induced by 7,12-dimethylbenzanthracene feeding of intact, thymectomized, or Freund's adjuvant-pretreated SJL mice. Four of six Thy-1-positive thymomas that arose in intact mice had a pseudodiploid stemline with one morphologically similar or identical marker. Banding analysis showed that the marker had arisen by the translocation of the distal part of one chromosome 15 to one X chromosome [t(X;ter 15)]. Two normal No. 15 chromosomes were also present in the same metaphase plates. These four Thy-1-positive lymphomas were thus trisomic for the distal part of chromosome 15. All 8 Thy-1-negative lymphomas, originating in the spleen or lymph nodes of thymectomized or adjuvant-pretreatment mice, had a trisomy of chromosome 12 and also a trisomy of either chromosome 3 or chromosome 18. These results further stress the importance of gene dosage effects, related to the distal part of chromosome 15, in Thy-1-positive T-cell leukemogenesis. The cytogenetic difference between the Thy-1-positive and -negative leukemias supports our hypothesis that nonrandom chromosomal changes in murine leukemias are dependent on the target cell type, rather than the inducing agent.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1980

Blood lymphocytes in infectious mononucleosis share the following characteristics with activated T cells: natural attachment, stable E rosetting and glucocorticoid sensitivity.

Blood lymphocytes of infectious mononucleosis (IM) patients, unlike these obtained from healthy individuals, exhibit the following characteristics of activated T cells: (1) "stable" E rosette formation; (2) natural attachment to various human normal and malignant cells; (3) sensitivity in vitro to the lytic effect of glucocorticoids. Although the IM T cells attach in vitro to all the human cells tested, they kill only the EBV genome carrying targets. The possibility is discussed that some of the activated T cells in IM result from a non-specific activation elicited by the T cells responding specifically to the EBV associated antigens.

Cell Adhesion↗
PubMed1980

[Testing the effectiveness of cerebrally active drugs. Preliminary communication on a test model for cerebrally active drugs in humans].

In a pilot study the feasibility of a new model in clinical pharmacology was investigated for testing cerebro-active drugs on healthy volunteers. For this study 6 volunteers were examined under room-air conditions (pO2 = 155 mmHg) and under a reduced oxygen mixture (12% O2, 88% N2, pO2 = 89 mmHg). Using the "Wiener Determinationsgeraet" (WDG) the subjects were tested as to their receptivity for complex information, their capacity for assimilating information, their reaction capacity, their reaction speed and reaction reliability. The results showed a stochastic connection between measured values on the WDG and the arterial oxygen partial pressure of the volunteers. These results justify additional studies with the described "hypoxia model" in order to test whether this reduction in capability in the healthy volunteers can be counteracted by application of cerebro-active drugs. This model could be used as a screening test for posology and pharmacodynamic effects in view of the further drug development in phase II studies on a larger number of patients.

Adult↗
PubMed1980

[Transient supernormality of AV-conduction (author's transl)].

A case is presented which is believed to demonstrate a transient supernormal phase of av-conduction in the presence of av-block complicating acute inferior wall myocardial infarction. During the initial period following the infarct there was a regular av-escape rhythm without av-conduction. Then on the 12th and 13th day supernormal av-conduction occurred. At the end of this period the supernormal phase became longer and more atrial impulses were conducted to the ventricles. Following the administration of atropine, there was a shortening of the supernormal phase to the previous values. The ECG taken one day later revealed normal av-conduction. It appears that supernormality occurred as a transient phenomenon during the phase of restitution of av-block, possibly by the ventricular complexes retrogradely invading the av-node.

Aged↗
PubMed1979

Abortive expression of the Epstein-Barr virus (EBV) cycle in a variety of EBV DNA-containing cell lines, as reflected by nucleic acid hybridization in situ.

A variety of Epstein-Barr virus (EBV) DNA-containing cell lines have been tested for the expression of the EBV-associated antigens EBNA (nuclear antigen), EA (early antigen), and VCA (viral capsid antigen), and for the presence of cells containing disproportionate amounts of EBV DNA. The antigen tests utilized immunofluorescence and 125I-labelled antibodies combined with autoradiography. EBV-DNA was detected by in situ hybridization with 3H-labelled EBV RNA complementary to P3HR-1 EBV DNA (P-EBVcRNA). The P-EBVcRNA has been shown to represent the majority of the P3HR-1 EBV DNA sequences. It was concluded that EBV DNA-containing cell lines can be divided into those that express only EBNA, those that express EBNA and EA and those that express EBNA, EA and VCA and also contain cells that undergo disproportionate EBV DNA synthesis. Consequently, in some cell lines there is an abortive expression of the EBV cycle in that some cells spontaneously express EA but fail to continue further to viral DNA synthesis. A similar pattern can be found after experimental induction of the EBV cycle, suggesting that related mechanisms govern the spontaneous expression of the EBV cycle and the extent of its inducibility.

Antigens, Viral↗
PubMed1979

Epstein-Barr virus-specific antibody-dependent cellular cytotoxicity in patients with Burkitt's lymphoma.

Coded sera from 54 patients with African Burkitt's lymphoma (BL) were titrated for antibodies against an Epstein-Barr virus (EBV)-induced membrane antigen in the antibody-dependent cellular cytotoxicity (ADCC) assay. The titers were then correlated with the progression of lymphoma growth following chemotherapy. In 74% of the patients with high ADCC titers (greater than 3,840), lymphomas showed partial or complete regression following therapy. In the medium-titered group (240-3,840), 36% of the lymphomas showed some response to therapy, while only 29% of the lymphomas in the low group (less than 240) responded to treatment. These preliminary results indicated that, as previously reported for patients with nasopharyngeal carcinoma, ADCC titers may be a prognotic value in patients with this EBV-associated disease. In an attempt to determine the identity of the ADCC antigen, some of these sera were examined for antibody to the four major MA components so far identified in the membrane of EBV-infected Raji cells. Sera with high ADCC titers in general contained antibody to the four major MA components, while low-titered sera usually contained antibody to three or less of these proteins. There were exceptions to this pattern, however, indicating that the ADCC antigen might differ from the four EBV-induced membrane components so far identified.

Antibodies, Viral↗