Evidence for a Persistent Viral Infection in a Cell Line Derived from Burkitt's Lymphoma

Interferon production potentials of various human lymphoblastoid cell lines

A number of human lymphoblastoid cells were examined concerning their ability to produce spontaneously liberated and virus-induced interferon (IFN). It was found that, in addition to B cells, various T and nonT-nonB lymphoblastoid cells responded well to Sendai virus infection to form IFN, the characterization of which has been recently reported (20). One B lymphoblastoid cell line from an infectious mononucleosis (IM) patient produced a large amount of IFN-alpha and might become an alternative source of IFN production. Among 68 cell lines examined, 35 cell lines liberated 10 U/ml or more of IFN spontaneously in culture fluid. The presence of Epstein-Barr virus (EBV) genome or its activation appears to have no correlation with the spontaneous liberation of IFN. Spontaneously produced IFN from three cell lines was characterized as IFN-alpha. Comparatively higher amounts of IFN were produced in cells from IM patients than those from Burkitt's lymphoma cases or healthy adults. Spontaneously produced IFN was detected more easily in cells transformed by EBV alone than in those transformed by EBV and a tumor promoter, TPA.

Spontaneous production of human interferon

Several established lines of human lymphoblastoid cells were evaluated for abilities to produce interferons. Some cell lines were able to produce interferon when induced with either Newcastle disease virus or Sendai virus, whereas others failed to produce detectable interferon when so induced. However, several cell lines were able to spontaneously produce interferon without induction. Spontaneously produced interferon was liberated by cells only during logarithmic growth phase, reaching levels ranging from about 10 reference units/ml of growth medium for some cell lines to 1000 reference units/ml for others. The interferons produced by induced lymphoblastoid cells and the spontaneously produced interferons were all characterized as type I human leukocyte interferon by high levels of cross-species antiviral activities on bovine cells and by neutralizations by antiserum to human leukocyte interferon but not by antiserum to human fibroblast interferon. However, analysis by electrophoresis in sodium dodecyl sulfate/polyacrylamide gels revealed that spontaneously produced interferon was less size heterogeneous than human leukocyte interferon, migrating as a single band of activity with a peak at 20,000 daltons, whereas human leukocyte interferon contained peaks of major activity at 23,000 and 18,000 daltons and virus-induced Namalva lymphoblastoid cell interferon migrated predominantly as the 18,000-dalton form. Also, although neither virus-induced primary leukocyte interferon nor any of the virus-induced lymphoblastoid cell interferons were neutralized by antiserum to mouse interferon, all of the spontaneously produced interferons were neutralized by antiserum to mouse interferons. These data suggest significant structural similarities between the active cores of certain interferons from phylogenetically diverse animal species.

Produção de interferon ou substância semelhante em culturas EB3 inoculadas com soros humanos contendo antígeno Austrália

Culturas de células EB3, quando inoculadas com soros humanos contendo antígeno Austrália, produzem interferon ou substância semelhante em títulos significativamente mais elevados do que as culturas controle, não inoculadas. As culturas de células EB3 inoculadas com soros humanos negativos para o antígeno Austrália comportam-se de modo idêntico às culturas controle, no que respeita aos títulos de interferon, ou substância semelhante. Sugere-se a possibilidade daquele efeito poder servir de indicador de uma possível interação entre as células EB3 e o antígeno Austrália.

Immunofluorescence in cells derived from Burkitt's lymphoma

Henle, Gertrude (Children's Hospital of Philadelphia, Philadelphia, Pa.), and Werner Henle. Immunofluorescence in cells derived from Burkitt's lymphoma. J. Bacteriol. 91:1248-1256. 1966.-Indirect immunofluorescence tests led to the brilliant staining of a small proportion of the cells in five different cultures derived from Burkitt's (African) lymphomas. The reaction was not restricted to the 17 sera from cases of this disease but extended to many sera from American individuals, whether healthy donors or patients suffering from a variety of illnesses. The incidence of positive sera increased with age from about 30% in childhood to > 90% in adults. Fluorescein-isothiocyanate-conjugated human gamma-globulins were suitable for direct staining of the same proportion of cells. The stained cells appeared to be in varying stages of degeneration, but cultural conditions leading to an increase in the cellular death rates failed to result in a rise in fluorescent cells. Several observations suggest that the stainable cells might be those which are seen to harbor virus particles under the electron microscope. Two cell lines derived from leukemic patients in this country also contained a small fraction of stainable cells but two others, and numerous primary human leukocyte cultures, gave consistently negative results. Attempts to relate the staining to known viral antigens have failed to implicate herpes simplex, varicella, cytomegalo, and reo viruses types 1, 2, and 3. The nature of the virus carried by the lymphoma cells as well as of the staining reactions remains to be determined.

Further observations of the lymphomas of African children

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