bluuebunny/crossref_metadata_2025_split huggingface dataset:
Classification and biological nature of established human hematopoietic cell lines
Authors: Nilsson Kenneth , Pontén Jan 
Published: February 2007

AbstractOver 200 established human hematopoietic cell lines of normal and malignant origin have been investigated by morphological and functional parameters. Employing morphology as the overriding parameter four types of lines were identified. (1) Lymphoblastoid cell lines, derived from normal and neoplastic hematopoietic tissue, were characterized by the wide morphologic flexibility of individual lymphoblastoid cells, constant association with Epstein‐Barr virus (EBV), polyclonal derivation, differentiation for immunoglobulin production (secretion) and their diploids. (2) Lymphoma cell lines. This type of line was established at a high frequency from Burkitt's lymphoma and rarely from other types of lymphoma, but never from patients without malignancy or with non‐lymphoma malignancies. Important characteristics were morphologic stereotypia within each line, monoclonal derivation, common but not obligatory association with EBV, variability in the expression of Ig synthesis (no production, or membrane bound Ig, or secretion) and aneuploidy. (3) Myeloma cell lines could only rarely be obtained from patients with myeloma. The basis for classification of these lines is their production of Ig identical to the myeloma protein in vitro. Other important distinguishing features were: plasma cell morphology, absence of EBV and aneuploidy. (4) The leukemia cell line (MOLT 4) was the only line with T‐cell characteristics and was easily distinguished from the other types. Important characteristics were a typical surface ultrastructure, absence of EBV and absence of immunoglobulin production. Individual lymphoblastoid lines were in principle identical whereas each line of the other three types had its own characteristic profile. The phenotypic characteristics of the lymphoblastoid lines were very stable during prolonged serial cultivation. Only in a few cases were secondary chromosomal, functional or morphologic alterations noted. We conclude that EBV‐carrying lymphoblastoid lines can be obtained from non‐neoplastic precursor cells from healthy as well as from diseased individuals. Lymphoma, myeloma and leukemia lines are only obtained from the respective neoplastic tissue but generally at a low frequency. With the exception of Burkitt's lymphoma, malignant hematopoietic tissue and leukemia frequently give rise to established cell lines in vitro of the lymphoblastoid type rather than lines derived from the neoplastic cells.
Lymphoblastoid transformation and kinetics of appearance of viral nuclear antigen (EBNA) in cord‐blood lymphocytes infected by epstein‐barr virus (EBV)
Authors: Yata J. , Desgranges C. , Nakagawa T. , Favre M. C. , De‐Thé G. 
Published: February 2007

AbstractHuman cord‐blood lymphocytes were infected with B95.8 Epstein‐Barr virus (EBV) before and after separation into B‐ and T‐cell populations. Lymphoblastoid cells exhibiting B‐cell characteristics appeared after 2 to 3 days of culture in the total population and in the separated B‐cell subpopulation but not in the T‐cell subpopulation. EBV nuclear antigen (EBNA) was detected concurrently with the appearance of lymphoblastoid cells. The proportion of EBNA‐positive cells corresponded to that of lymphoblastoid cells, and reached 50% after 4 days. EBNA was present only in cells with B‐cell markers. These observations indicate that only B‐cells are susceptible to EBV infection, that the transformation occurs within a few days and that EBNA is a valid early marker for susceptibility to EBV transformation.
Studies on a gross‐virus‐induced lymphoma in the rat. II. The role of cell‐membrane‐associated and serum p30 antigen in the antibody and cell‐mediated response
Authors: Knight R. A. , Mitchison N. A. , Shellam G. R. 
Published: February 2007

AbstractThe internal viral protein, p301, has been identified by cytotoxicity tests using xenogeneic sera, on MuLV‐G‐induced rat lymphoma cells. In this system internal virion antigens, and in particular p30, are cytotoxic target antigens for syngeneic antibody and cell‐mediated cytotoxicity; p30 is also present in the serum of rats with progressively growing lymphomas, and is the principal antigen responsible for the inhibition of cell‐mediated cytotoxicity produced by these sera.
Cellular basis for the immune response to methylcholanthrene‐induced tumors in mice. Heterogeneity of effector cells
Authors: Kearney R. , Basten A. , Nelson D. S. 
Published: February 2007

AbstractImmune resistance to methylcholanthrene‐induced tumors has two phases, an early specific and a late non‐specific phase. Both phases were found to be T‐cell‐dependent in vivo. Thus, adult thymectomized, irradiated, bone‐marrow‐protected mice bearing H‐1 tumor isografts showed impaired resistance to challenge with homologous (H‐I) and heterologous (H‐3) tumor cells. In each case resistance was restored by injection of thymus cells. In vitro analysis of the cellular basis of resistance revealed that different mechanisms were involved in the two phases. The cytotoxic effect of immune spleen cells taken during the early specific phase was inhibited by pretreatment with anti‐θ serum and complement and by removal of macrophages. Neither procedure, however, interfered with the cytotoxic potential of immune spleen cells taken during the late non‐specific phase of immunity. Passage of immune spleen cells through rabbit‐IgG anti‐mouse immunoglobulin‐coated columns (which yielded a T‐cell‐enriched, B‐cell‐depleted population) resulted in abrogation of cytotoxicity whether the cells were obtained during the early or the late phase of resistance. The inability of late‐phase spleen cells to kill was explicable in terms of B‐cell removal since T‐cells and macrophages had been shown to be ineffective at that time. In contrast, the failure of column‐treated cells from the early phase to kill was found to be due to removal of adherent cells rather than B‐cells since cytotoxicity (1) was abrogated by passage through control columns coated with rabbit‐IgG anti‐sheep red blood cell antibody which did not retain B‐cells and (2) could be restored by addition of immune macrophages (from anti‐θ serumtreated spleens). Taken together, these results indicate that the cellular basis of immune resistance to methylcholanthrene‐induced tumors is heterogeneous. The early specific phase seems to be mediated by an interaction between T‐cells and macrophages; the late non‐specific phase, although T‐cell dependent in its induction, depends on a different effector mechanism, possibly involving a cell or its products of the B lineage.
Effect of cordycepin on the replication of type‐c rna tumor viruses
Authors: Richardson L. S. , Ting R. C. , Gallo R. C. , Wu A. M. 
Published: February 2007

AbstractCordycepin (3′‐deoxyadenosine) was previously shown to inhibit virus production induced by iododeoxyuridine from murine fibroblasts (Wu et al., 1972). We now report that the inhibitory effect of cordycepin results in a reduction of the number of cells producing virus as measured by the infectious center assay and fluorescent antibody technique. Cordycepin has a much greater inhibitory effect on viral replication than on transformation of normal rat kidney cells by murine sarcoma virus since viral production was greatly reduced (seven‐ to 35‐fold) with 5–10 μg/ml of cordycepin while viral transformation was only slightly inhibited (two‐fold reduction in focus‐forming units) with the same concentration of cordycepin. Inhibition of viral production is most effective if the compound is present during the first 24 h after infection.
Distinction between tumor‐specific transplantation antigen and virion antigens in solubilized products from membranes of virus‐induced leukemic cells
Authors: Chang Kenneth S. S. , Law Lloyd W. , Appella Ettore 
Published: February 2007

AbstractA membrane antigen from RBL‐5 leukemic cells that was solubilized and partially purified is further characterized in this study. This soluble antigen is capable of immunizing syngeneic hosts to reject neoplastic cells and thus resembles TSTA. It also induces cytotoxic antibody in syngeneic hosts capable of specifically lysing RBL‐5 cells in vitro. RBL‐5, however, releases infectious virus (RLV); it was necessary therefore to rule out virus or structural virion antigens as the effective immunogen. Infectious virus was not detectable in our initial crude membrane (CM) material, nor in the papain‐solubilized CS or the G‐150 Sephadex‐chromatographed fraction. Virus‐neutralizing antibody was not detected, under stringent assay conditions, in the syngeneic anti‐CM sera. Antigen preparations CM, CS and the chromatographed fractions F1, F2 and F3 were assayed in a complement‐fixation test against broad‐reacting antisera capable of detecting virus envelope antigen and gs antigen and against syngeneic antisera. Although our antigen preparations were positive for virion antigens. CS and F2 contained an antigen that reacted only with syngeneic antiserum. These same fractions were those reactive as immunogens. On the basis of these data, it is postulated that a cellular membrane component, other than viral, functions as TSTA.
Activation of c‐type viruses during skin graft rejection in the mouse. Interrelationships between immunostimulation and immunosuppression
Authors: Hirsch Martin S. , Ellis David A. , Kelly Ann P. , Proffitt Max R. , Black Paul H. , Monaco Anthony P. , Wood Mary L. 
Published: February 2007

AbstractBoth mouse‐tropic and zenotropic C‐type RNA viruses were activated in BALB/c mice during rejection reactions against skin grafts from mice differing at the major histocompatibility locus (A/J) or sharing this locus (DBA/2). Animals that maintained their skin grafts following immunosuppression with antilymphocyte serum (ALS) or cyclophosphamide had a much higher incidence of virus‐positivity than animals that did not receive ALS or cyclophosphamide, or that rejected their skin grafts despite immunosuppressive therapy. ALS itself activated type‐C viruses from a small proportion of BALB/c mice whereas cyclophosphamide alone did not. Type‐C viruses were detected in spleens and regional nodes draining skin‐graft sites between 1 and 2 weeks following transplantation; thereafter they reached maximum titers in spleens. Viruses were not detected at skin‐graft sites, in tails or in thymuses of grafted animals. Virus activation was associated with splenic histological changes consisting of germinal center formation, diffuse hyperplasia of reticulum cells, depletion of periarteriolar lymphocytes and hyperplasia of red pulp hematopoietic elements.
Eb virus‐associated nuclear antigen production and cell proliferation in adult peripheral blood leukocytes inoculated with the qimr‐wil strain of eb virus
Authors: Moss D. J. , Pope J. H. 
Published: February 2007

AbstractA nuclear antigen, apparently the Epstein‐Barr virus (EBV)‐associated nuclear antigen (EBNA), was detected by anticomplement immunofluorescence (ACIF) tests in adult human peripheral blood leukocytes infected with the QIMR‐WIL strain of EBV. EBNA was not detectable at 24 h but appeared in about 11% of the cells by 3 days, and by 5 days up to 64% of the cells were positive. Proliferation of EBNA‐positive cells at this stage was confirmed by autoradiography. There was a good correlation between the concentration of virus and the number of EBNA‐positive cells in the first 5–7 days. The subsequent course of events was found to be influenced by the initial cell concentration and the time of subculture. EBNA production was delayed in cells infected with higher dilutions of virus but subsequently appeared in a high proportion of cells. Indirect immunofluorescence failed to detect viral capsid antigen (VCA) or early antigen (EA) by 10 days. The results show that EBV infection was abortive and that the critical events of viral transformation occurred within the first few days.
Helper specificity for retrieval of defective friend virus
Authors: Howard Fieldsteel A. , Kurahara Carole , Dawson Peter J. 
Published: February 2007

AbstractA Friend virus‐induced reticulum‐cell sarcoma from BALB/c mice has been cultivated in vitro in our laboratory for more than 11 years and contains no detectable evidence of virus. However, Friend virus could be retrieved readily from the tissue cultures by any of several lymphatic leukemia viruses belonging to the Friend‐Moloney‐Rauscher (FMR) group, as long as the helper viruses were actively replicating in a culture. Helper activity appeared to be highly specific and limited to the FMR group including the B‐tropic Tennant leukemia virus which produced a B‐tropic Friend virus pseudotype. The naturally occurring type AKR murine leukemia viruses and the related Gross passage A virus failed both in vivo and in vitro to retrieve the Friend virus genome from the virus‐free tumor cells.
Transplantable murine tumors release mouse‐tropic and xenotropic type‐c viruses
Authors: Lieber Michael M. , Sherr Charles J. , Todaro George J. 
Published: February 2007

AbstractTransplantable mouse tumors used in many areas of cancer research generally produce several host‐range classes of infectious type‐C virus. The release of virus from such tumors should be considered in the design and evaluation of experiments in which they are used.
Competition radioimmunoassay for mason‐pfizer monkey virus: Comparison with recent isolates
Authors: Yeh Jen , Ahmed Mumtaz , Lyles Joan , Larson David , Mayyasi Sami A. 
Published: February 2007

AbstractThe major core protein of Mason‐Pfizer monkey virus was purified by DEAE ion exchange column chromatography and shown to be 27,000 daltons (p27). Following the characterization of monospecific antisera prepared against p27, a radioimmunoassay was developed with these reagents and competition experiments were done with some of the recent M‐PMV‐like isolates as well as with other oncornaviruses. Results suggest that three of the viruses tested, AO, X‐381 and FTP‐1, are similar to M‐PMV while J‐96 virus is related, but not identical, to M‐PMV. It is also shown that competition RIA can be used successfully to detect the presence of viral proteins in tissue homogenates and cell extracts.
Cancer of asians in kenya
Authors: Chopra S. A. , Linsell C. A. , Peers F. G. , Chopra F. S. 
Published: February 2007

AbstractThe frequency of various cancers among Indian immigrants in Kenya was compared to corresponding data among native Africans and Indians in the regions of India from which most of the studied population originally migrated. The Kenyan Indians do not have the cancer pattern of their home country nor do they have the cancer pattern of indigenous Africans. They have instead, like Europeans and North Americans, a higher risk of cancer of the lung, breast and the large intestine. It is suggested that this is related to environmental factors and variations in living habits.
Prostaglandin synthesis inhibition: Effect on bone changes and sarcoma tumor induction in balb/c mice
Authors: Strausser Helen R. , Humes John L. 
Published: February 2007

AbstractAn increase in prostaglandins (PGs) of the E series has been demonstrated in Moloney sarcoma virus (MSV)‐induced leg tumors of 6‐week‐old BALB/c male mice. The level of the hormone has been shown to increase with the tumor diameter and decrease with tumor regression. At the peak of tumor size the tibial bones of the mice were considerably deformed, suggesting osteoclastic activity. The systemic calcium level was not elevated, indicating possible release of calcium into the local tumorous area. In mice treated with indomethacin the tumors failed to develop and PG levels were markedly lower. Tibial bones of treated mice were similar in appearance to those of control, non‐tumorous mice. PG levels of DBA/1J mice bearing extensive Cloudman S91 melanomas were not elevated and no bone deformation was seen. When contrasted with studies of immuno‐depressed mice the results suggest that indomethacin acted in conjunction with and possibly to restore the PG‐induced depression of the immune system in preventing tumor development. It is also hypothesized that indomethacin, by suppressing the PG‐mediated calcium release from bone, could be operative in inhibiting tumor growth.
Establishment of a continuous tumor‐cell line (PANC‐1) from a human carcinoma of the exocrine pancreas
Authors: Lieber Michael , Mazzetta Joann , Nelson‐Rees Walter , Kaplan Michael , Todaro George 
Published: February 2007

AbstractAn epithelioid cell line, started from a human pancreatic carcinoma of ductal cell origin, has been maintained in culture for over 2 years and has been subcultured more than 40 times. The PANC‐1 cell line has a doubling time of 52 h and G6PD activity of the slow mobility or B type. Chromosome studies show a modal number of 63 with three distinct marker chromosomes and a small ring chromosome. The malignant nature of the PANC‐1 cell line was verified by: (1) the ready growth of PANC‐1 cells in soft agar and on top of a fibroblast monolayer; and (2) the formation of a progressively growing anaplastic carcinoma after injection of a nude‐athymic mouse with PANC‐1 cells.
Epstein‐Barr virus‐induced cap formation in human lymphoblastoid cells
Authors: Hinuma Yorio , Suzuki Masahiro , Sairenji Takeshi 
Published: February 2007

AbstractRedistribution and consequent cap formation of Epstein‐Barr virus adsorbed to human lymphoblastoid cells were studied by indirect membrane immunofluorescence carried out at 0° C. When EBV was adsorbed on cells at 0° C, the cell sur face fluorescence had a mostly ring‐like pattern. However, the ring cells could be transformed into cap cells when warmed at 37° C. This cap formation could be induced by EBV alone without participation of antibodies involved in the immunofluorescence procedure. The cap formation was temperature‐ and pH‐dependent, and was reversibly inhibited by sodium azide or some sugars. Thus the EBV‐induced cap formation was analogous to that induced by antibodies or ligands on other lymphoid cells.
Murine sarcoma virus related nucleic acid sequences in a non‐transforming virus derived from an interspecies pseudotype sarcoma virus
Authors: Okabe Hiromi , Gilden Raymond V. , Hatanaka Masakazu 
Published: February 2007

AbstractA number of sarcomagenic viruses recovered from hamster tumors induced originally by Moloney sarcoma virus or several of its mouse pseudotypes appear to be interspecies pseudotypes with structural proteins of hamster type‐C viruses and nucleic acid sequences of both mouse and hamster specificity. A non‐transforming virus (GLOH−) recovered from a sarcomagenic virus preparation obtained from a tumor induced by the Gross pseudotype of Moloney sarcoma virus was previously shown to retain mouse sequences. The ability to discriminate readily between Gross and Moloney viruses by molecular hybridization, especially with regard to thermal stability of inter‐strain hybrid molecules, and the stability of Moloney virus sequences in a rat‐mouse interspecies pseudotype, made it possible to specify that the mouse virus‐specific sequences in GLOH− are derived from Moloney virus and not Gross. Thus, even though GLOH− is non‐transforming in vitro or in vivo, it still retains sequences highly related to Moloney sarcoma virus. The lack of transforming ability is thus probably based on loss or change of specific sequences necessary for transformation at some point in the history of this virus.
Tumour inhibition mediated by BCG in immunosuppressed rats
Authors: Moore Michael , Lawrence Nicola , Nisbet Norman W. 
Published: February 2007

AbstractTwo rat sarcomas (CC5 and P7) which grow progressively on transplantation into normal syngeneic hosts failed to develop when injected in admixture with the Glaxo strain of Bacillus Calmette‐Guérin (BCG). Under comparable conditions, the local development of a third neoplasm (P8) was temporarily inhibited and the number of pulmonary metastases significantly reduced. Experiments were undertaken to determine the extent to which the anti‐tumour action of BCG required an immunocompetent host. Rats were immunosuppressed by sub‐lethal whole‐body irradiation (450 R), with or without prior thymectomy and challenged with inocula of mixed BCG and tumour cells when their capacity to respond to bacterial, tumour and unrelated antigens was maximally depressed. In non‐sensitized immunosuppressed rats, the ability of BCG to limit tumour outgrowth was abrogated only in the case of sarcoma CC5. For this neoplasm, immunogenic in syngeneic hosts by conventional criteria, there was a statistically significant difference in the number of tumours in immunosuppressed rats (51%) compared with non‐sensitized immunocompetent controls (6%). Presensitization to either bacterial or tumour antigens, prior to thymectomy and/or irradiation, fully restored the tumour‐inhibitory capacity of BCG. By contrast, sarcoma P7 was not significantly less susceptible to BCG‐induced regression in non‐sensitized immunosuppressed rats than in non‐sensitized normal rats; and sarcoma P8 similarly failed to reveal any significant differences in susceptibility to BCG affecting primary or secondary tumour development. It is concluded that tumours may vary widely in their sensitivity to host reactions aroused by BCG. Certain neoplasms, exemplified by sarcoma CC5, require participation of an immune reaction of delayed hypersensitivity type for optimal destruction at BCG sites, while for others (e.g. sarcoma P7) an immunoreactive component of this type is not essential. By contrast, a third category of tumour (e.g. sarcoma P8) is relatively resistant to host reactions induced by the mycobacteria. An important component of BCG‐mediated tumour inhibition is not dependent on an immunologically intact host.
Genetic variation of in vitro cytolytic activity and in vivo rejection potential of non‐immunized semi‐syngeneic mice against a mouse lymphoma line
Authors: Kiessling Rolf , Petranyi Gyözö , Klein George , Wigzell Hans 
Published: February 2007

AbstractSpleens of normal young mice of certain genotypes contain lymphocytes that can kill strain A‐derived YAC‐1 and some other in vitro‐grown Moloney lymphoma lines in a 51Cr‐release cytotoxic test. We have previously shown that mouse strains can be classified as high or low reactors in this test. F1 hybrids between low‐ and high‐reactive strains are high‐reactive. In the present study, strain‐A mice and eight different A F1 hybrids were tested in parallel for their spleen‐cell‐mediated killing effect in vitro and their ability to reject graded numbers of YAC ascites or in vitro cultivated cells in vivo. There was a clear correlation between in vitro cytotoxicity and in vivo rejection in all tested genotypes. In segregating (A × C57Bl) × A backcross mice, in vivo rejection of YAC cells was H‐2 linked. This is in line with the earlier backcross analysis of the in vitro cytotoxicity, suggesting a polygenic control with at least one H‐2 linked factor.
Influence of interferon on the synthesis of virus particles in oncornavirus carrier cell lines. III. Survey of effects on A‐, B‐ and C‐type oncornaviruses
Authors: Billiau A. , Edy V. G. , DeClercq E. , Heremans H. , DeSomer P. 
Published: February 2007

AbstractThe effect of interferon on the synthesis and release of A‐, B‐ and C‐type viruses by oncornavirus carrier lines was studied. Murine cell lines were selected which carry either of these viruses and are sensitive to the antiviral effect of interferon, as measured by inhibition of vesicular stomatitis virus. Release of C‐type virus was found to be highly sensitive. Release of B‐type virus, on the contrary, was only marginally inhibited. Synthesis of intracisternal A‐type particles was finally not inhibited by interferon pretreatment. These differences between infectious C‐type and non‐infectious A‐ and B‐type viruses may reflect fundamental differences in the synthesis of these viruses.