Direct outgrowth of in vivo Epstein-Barr virus (EBV)-infected chronic lymphocytic leukemia (CLL) cells into permanent lines.

In the course of our efforts to characterize the EBV-carrying cells that are responsible for direct growth or the 2-step mechanism, based on virus release from the explanted cells and subsequent transformation of previously uninfected cells, we have encountered an unusual CLL patient who carried a small subpopulation of in vivo EBV-infected leukemia cells. These were predominantly present in the low-density fraction and grew into EBV-carrying lines upon explantation after a relatively short latency period, 3-4 weeks. Cytogenetic examination conclusively proved the leukemic origin of the established CLL lines.

Buoyant density characterization of neoplastic cell populations in patients with chronic B-lymphocytic leukemia.

Leukemic cells from a series of patients with chronic B-lymphocytic leukemia (CLL) were analyzed for their buoyant density on discontinuous Percoll gradients. The density profile varied markedly between different patients and also between samples from different body compartments within the same patient. A good correlation was observed between buoyant density and maturation stage of the leukemic clones as judged by Ig-expression and their reactivity with a panel of monoclonal antibodies.

Conversion of the lymphoma line "BJAB" by Epstein-Barr virus into phenotypically altered sublines is accompanied by increased c-myc mRNA levels.

The steady-state level of c-myc proto-oncogene mRNA was investigated in the EBV-negative human B-lymphoma line BJAB and 2 sublines that have been converted by EBV into stable EBV-genome-carrying and EBNA-positive status. The EBV-converted sublines expressed c-myc at a 2- to 6-fold higher level than the original BJAB during exponential growth. The EBV-positive BJAB lines are known to differ from the parent line in several phenotypic characteristics, including increased agarose clonability, lower serum requirement and, in one case, increased tumorigenicity in nude mice.

Characterization of EBV-carrying B-cell populations in healthy seropositive individuals with regard to density, release of transforming virus and spontaneous outgrowth.

Peripheral or tonsil lymphocyte populations of EBV-seropositive donors give rise to EBV-carrying LCLs upon in vitro explantation. Such lines can arise either by a 2-step mechanism, namely release of virus from some of the explanted cells followed by infection of previously uninfected B cells, or by direct outgrowth of virus-harboring B cells (Rickinson et al., 1974; Dalens et al.

B cell activation by the nontransforming P3HR-1 substrain of the Epstein-Barr virus (EBV).

The P3HR-1 substrain of Epstein-Barr virus does not transform B cells. This defect is known to be determined by the loss of the coding sequence for the nuclear antigen EBNA-2. The virus can attach to and enter resting B cells.

The influence of wheat bran and sugar-beet pulp on the digestibility of dietary components in a cereal-based pig diet.

The influence of added wheat bran or dried sugar-beet pulp on the apparent digestion of dietary components was examined in pigs fitted with duodenal and terminal ileal cannulas. The pigs were fed a basal cereal-based diet alone or substituted at a level of 33% by wheat bran or beet pulp. Neither fibrous component influenced the digestibility of starch, but inclusion of beet pulp decreased dry matter content and digestibility of ash, protein and fat in the ileum and fecal digestibility of fat.

Production of chemokinetic inhibitory factor (CIF) by normal blood and spleen B lymphocytes.

We have recently reported the partial purification and characterization of of a new lymphokine, the heat-labile chemokinetic inhibitory factor (CIF) which inhibits neutrophil movement. We have also shown that this lymphokine is produced and secreted by cultured B-chronic lymphocytic leukaemia (CLL) cells in vitro. The present study shows that highly purified resting normal B lymphocytes from blood and spleen have the capacity to produce CIF spontaneously.

Use of a nylon-bag technique for pig feed digestibility studies.

1. The use of a nylon-bag technique for pig feed digestibility determination was studied. Bags, measuring 25 x 40 mm and containing feed samples, were introduced into the pig gastrointestinal tract through a duodenal cannula, and recovered in the faeces between 23 and 69 h later.

Surface marker characterization of EBV target cells in normal blood and tonsil B lymphocyte populations.

Human FACS-sorted B lymphocyte subpopulations were investigated for their susceptibility to immortalization by Epstein Barr virus (EBV). Only B cells reacting with the monoclonal antibody B2 were immortalized, whereas cells reacting with anti-human IgG or the monoclonal antibody BB2 were not responding. Cells positive or negative for IgM, IgD, Burkitt's lymphoma antigen (BLA), BB1, and HB2 were all transformed by EBV.

The large sialoglycoprotein of human lymphocytes. I. Distribution on T and B lineage cells as revealed by a monospecific chicken antibody.

Chickens were immunized with highly purified large sialoglycoprotein of human lymphocytes (L-LSGP; gp 150) which was isolated from neuraminidase-treated normal peripheral blood lymphocytes by affinity chromatography to HP-Sepharose and further purified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Antibodies isolated from plasma and egg yolk were highly specific for desialylated L-LSGP (apparent molecular mass approximately 150 kDa). The antigenic sites recognized by the antibodies are probably located in the peptide moiety of the molecule since antibody binding to lymphocytes was not inhibited by a variety of different sugars or abrogated by absorption on various erythrocytes.

Capacity of B-lymphocytic lines of diverse tumor origin to produce and respond to B-cell growth factors: a progression model for B-cell lymphomagenesis.

Human cell lines established from cases of acute lymphoblastic leukemia, lymphosarcoma, Burkitt's lymphoma and multiple myeloma and representing stages of B-lymphocyte development ranging from pre-B through to plasma cells, were assessed for their ability to produce and respond to B-cell growth factors (BCGF). All B-cell lines studied were found to be constitutive producers of a growth activity which assisted the S-phase entry of normal activated B-cells and provided growth support for lymphoblastoid cells transformed by Epstein-Barr virus. Furthermore, all lines responded by enhanced proliferation to supernatants from a BCGF-producing T-cell hybridoma.

Leukocyte migration inhibitory factor production by activated lymphocytes representing immunological memory or virus-receptor interaction: response of T cell subsets to Epstein-Barr virus nuclear antigen, response of B cells to UV inactivated Epstein-Barr virus.

Both T and B lymphocytes are known to produce leukocyte migration inhibitory factor (LIF) after appropriate activation. We showed that EBV nuclear antigen (EBNA) triggered T cells for LIF production in an immunologically specific way: only T cells of seropositive individuals responded. Both Fc receptor positive and negative T cells produced LIF, and the presence of macrophages was necessary.

Soluble factor requirements for the autostimulatory growth of B lymphoblasts immortalized by Epstein-Barr virus.

B lymphoblasts immortalized by the Epstein-Barr virus (EBV) exhibit autocrine growth stimulation--that is they release a soluble activity to which they respond by growth. A minimally supplemented serum-free medium conditioned by lymphoblastoid cells in their log phase of growth (LCL-CM) was found to contain autostimulatory activity allowing us to explore the mechanism of autocrine growth for these cell-types in defined conditions. Below cell densities capable of supporting autonomous growth, continued proliferation in serum-free medium was dependent on both added LCL-CM and transferrin.

Phenotypic modulation of chronic lymphocytic leukemia cells by phorbol ester: induction of IgM secretion and changes in the expression of B cell-associated surface antigens.

Freshly explanted neoplastic populations from 22 cases of phenotypically well-characterized chronic type B lymphocytic leukemia were studied for their capacity to respond to the phorbol ester TPA in vitro. In all but four cases the secretion of IgM was either induced or increased, often to a high level. In contrast, the export of free immunoglobulin (Ig) light chains, an almost consistent feature of the B lymphocytic leukemias, remained relatively constant after TPA treatment.

TPA (12-O-tetradecanoyl-phorbol-13-acetate) activation and differentiation of human peripheral B lymphocytes.

The effect of the tumour-promoting phorbol ester TPA (12-O-tetradecanoyl-phorbol-13-acetate) on normal human peripheral blood and tonsil B lymphocytes was investigated. A strong DNA-synthesis response with the maximum at day 4 was detected. This response was, however, inhibited by increasing concentrations of serum in the medium.

Epstein-Barr virus susceptibility of normal human B lymphocyte populations.

Human blood and tonsil B lymphocytes were fractionated on density gradients and tested for virus binding and penetration into the cells. Epstein-Barr Virus (EBV) transformation was detected by immunofluorescence staining for EBV-determined nuclear antigen (EBNA). EBV bound to and penetrated all B cell populations, but only the high density populations were transformed.

Leu 7+ (HNK-1+) cells. II. Characterization of blood Leu 7+ cells with respect to immunophenotype and cell density.

In the present study, combined methods (indirect immunofluorescence with monoclonal antibodies, Percoll density fractionation, FACS analysis, and the cytotoxicity test) were used for further characterization of peripheral blood Leu 7+ cells (human NK and K cells). The Leu 7+ cell content was found to be relatively higher in the low-density cell fraction in which cells of large granular lymphocyte morphology predominated. However, Leu 7+ cells were also present in intermediate and high-density fractions.

Phenotypes in chronic B-lymphocytic leukemia probed by monoclonal antibodies and immunoglobulin secretion studies: identification of stages of maturation arrest and the relation to clinical findings.

Neoplastic populations from 25 cases of B-lymphocytic leukemia (B-LL) were investigated in an attempt to define the stages of maturation arrest represented in this disease and the relationship, if any, to various clinical parameters. Intrinsic to this study was the expression of a number of B-cell antigens defined by monoclonal antibodies. These included antibodies to B1 and B2, both expressed exclusively on B lymphocytes, but with the latter probably restricted to a narrow window of differentiation, BB-1 and LB-1, both markers of activated lymphocytes, and 38.

Relationship between the amounts of EBV-DNA and EBNA per cell, clonability and tumorigenicity in two ebv-negative lymphoma lines and their EBV-converted sublines.

The effect of EBV-conversion of two EBV-negative lymphoma lines (Ramos and BJAB) on agarose clonability and tumorigenicity in nude mice was explored. The cloning frequency was increased in all 9 sublines investigated, between 1.1 and 4.

Epstein-Barr virus (EBV)-induced lymphoproliferative disease in cotton-topped marmosets.

Six cotton-topped marmoset monkeys (Sangiunus oedipus) were inoculated with 10(5) transforming units of B95-8 virus, and two of them developed fatal lymphoproliferative disease. The EBV-carrying tumor cells from these marmosets had the following characteristics: (1) they were polyclonal by surface immunoglobulin and immunoglobulin production in vitro; (2) they had no specific chromosome abnormalities, and (3) they failed to form colonies in large percentages in agarose. It is proposed that a spectrum of phenotypes of EBV-induced lymphoproliferative diseases in the cotton-topped marmosets may be identified and are more akin to fatal infectious mononucleosis or X-linked lymphoproliferative syndrome than to Burkitt's lymphoma.

In vitro differentiation of chronic lymphocytic leukaemia cells with a small pre-B-like phenotype.

Neoplastic populations from three cases of chronic lymphocytic leukaemia (CLL) which had features consistent with a maturation arrest at the 'small pre-B' stage are described. The cells were small and rounded with a scanty cytoplasm and stained for mu heavy chains but not light chains intracellularly while surface immunoglobulin (SmIg) was either undetectable or expressed sparsely on a minority of cells. Other features included the weak expression of B1, a lack of B2, an absence of the common acute lymphoblastic leukaemia antigen (cALLA), the presence of Ia and a variable expression of the receptors for Fc gamma and C3.

Immune deficiency in the X-linked lymphoproliferative syndrome. II. Immunoregulatory T cell defects.

Surface phenotypic markers and the function of lymphocytes in patients affected with the X-linked lymphoproliferative syndrome (XLP) were studied. This syndrome is characterized by a defective response to infection with Epstein Barr virus (EBV). Normal numbers of B and T cells were detected with anti-Ig and monoclonal OKT3 antisera, respectively.