sepharose and Burkitt-Lymphoma

Binding of fibroblast growth factors (FGFs) to receptor tyrosine kinases (FGFRs) and signaling is facilitated by binding of FGF to heparan sulfate proteoglycans (HSPGs). There are multiple families of HSPGs, including extracellular and cell surface forms. An important and potentially controversial question is whether cell surface forms of HSPGs act as positive or negative regulators of FGF signaling. This study examines the ability of the cell surface HSPG syndecan-1 to regulate FGF binding and signaling. HSPG-deficient Raji lymphoma cells, expressing a transfected syndecan-1 cDNA (Raji S1 cells), were used as HSPG "donor" cells. BaF3 cells, expressing an FGFR1 cDNA (FR1C-11 cells), were used as FGFR "reporter" cells. Using Raji S1 cells preincubated with FGF, it was found that they formed heterotypic aggregates with FR1C-11 cells in the presence of FGF-2, but not FGF-1. In addition, the FR1C-11 cells demonstrated FGF-2, but not FGF-1, dependent survival when cultured on fixed Raji S1 cells. Thus, Raji syndecan-1 1) differentially regulates the binding and signaling of FGFs 1 and 2 and 2) acts as a positive regulator of FGF-2 signaling.

Topics: Animals; Burkitt Lymphoma; Fibroblast Growth Factor 2; Heparin; Heparitin Sulfate; Humans; Membrane Glycoproteins; Mice; Microspheres; Protein Binding; Proteoglycans; Receptor Protein-Tyrosine Kinases; Receptor, Fibroblast Growth Factor, Type 1; Receptors, Fibroblast Growth Factor; Sepharose; Signal Transduction; Syndecan-1; Syndecans; Tumor Cells, Cultured

The Epstein-Barr virus (EBV)-negative Burkitt lymphoma (BL) line BL-41, and 5 independently established EBV-converted sublines, derived by infection with a transforming (B95-8) or a nontransforming (P3HR1) strain of EBV, were compared for clonability in semi-solid agarose and for tumorigenicity in immuno-suppressed mice. One P3HR1 viral convertant and 3 out of 4 B95-8 virus-converted sublines had a high (greater than 40%) agarose clonability, like the BL 41 parent, and were slightly more tumorigenic than BL-41. In contrast, the fourth B95-8 converted subline, BL-41/95, was virtually non-tumorigenic and its agarose clonability was much lower (3-23%). It showed a more drastic shift towards an LCL-like phenotype than the other convertants as reflected by high HLA class-I and EBV-encoded latent membrane protein (LMP) expression. BL 41/95 still contains the 8;14 IgH/myc translocation, carried by the parental line, and maintains the same relatively high steady-state level of c-myc mRNA and protein as the highly tumorigenic convertants. We conclude that the tumorigenicity of BL41/95 has been suppressed by a gene that acts at a level beyond the expression of the activated oncogene, in the same way as the revertants isolated from ras and SV-40-transformed cultures (Klein, 1987b; Bassin and Noda, 1987).

Topics: Animals; Burkitt Lymphoma; Cell Transformation, Viral; Cloning, Molecular; Culture Media; Mice; Oncogene Protein p55(v-myc); Phenotype; Retroviridae Proteins; RNA, Messenger; RNA, Neoplasm; Sepharose; Translocation, Genetic; Tumor Cells, Cultured

We have compared the growth in agarose medium of two EBV-negative Burkitt lymphoma lines, BJAB and Ramos, and that of their EBV-converted derivatives. Optimal conditions for growth in agarose medium are described. The original EBV-negative lines can grow in agarose to a high efficiency, provided a critical level of cell concentration is attained. Below this level, there is no growth at all. EBV-converted sublines form colonies at a much lower cell concentration, and their maximal plating efficiency is higher. These differences may be related to a super-transformation state induced in these cells by EBV.

Topics: Burkitt Lymphoma; Cell Count; Cell Line; Cell Transformation, Viral; Clone Cells; Culture Media; Herpesvirus 4, Human; Humans; Polysaccharides; Sepharose

Plastic dishes were coated with an agarose layer. The layer was modified by covalently binding proteins to it, using the CNBr-method. Cells were seeded on the dishes and the number of attached cells was evaluated. The specificity of the attachment was demonstrated by showing that cells, carrying specific membrane-bound immunoglobulins, attached only to the corresponding anti-immunoglobulins. This indicated that the method could be used for cell sorting. The attachment of cells to proteins was influenced by the amount of bound protein, incubation time, temperature and the degree of trypsinization. Most attached cells were viable for several days and when dying they detached. Detailed morphological and cytochemical analyses of the dynamics of attachment and cytoplasmic spreading on the chemically well-defined surfaces were possible using the new method.

Topics: Burkitt Lymphoma; Cell Adhesion; Cell Line; Concanavalin A; Glioma; Humans; Leukemia; Lymphoma, Non-Hodgkin; Neuroglia; Polylysine; Polysaccharides; Protamines; Protein Binding; Proteins; Sepharose

Con A-Sepharose affinity chromatography may be used in the analysis and classification of immune complexes. Experiments with model immune complexes suggest that the degree of affinity of an immune complex for Con A-Sepharose is determined by the antigen rather than the IgG antibody of the complex. It is possible that partial characterization of unknown antigens linked to IgG in immune complexes may be achieved in many diseases. Preliminary explorations with selected human sera indicate that the IgG containing immune complexes in Burkitt's lymphoma and nasopharyngeal carcinoma have affinity for Con A-Sepharose. By contrast IgG containing immune complexes in chronic hepatitis B seem to lack affinity for Con A-Sepharose.

Topics: Antigen-Antibody Complex; Burkitt Lymphoma; Chromatography, Affinity; Chronic Disease; Concanavalin A; Hepatitis B; Humans; Immune Sera; Immunoglobulin G; Nasopharyngeal Neoplasms; Sepharose

Sera of individuals with Burkitt's lymphoma and nasopharyngeal carcinoma, tested by consumption of hemolytic complement, were found by comparison with healthy individuals to have significantly increased levels of circulating immune complexes. The identity of the immune complexes was established by sucrose density gradient ultracentrifugation, which showed them to sediment between 10 and 19S. As they were adsorbable by rheumatoid factor--Sepharose 4B conjugates, it appeared that these complexes were composed of IgG. The complexes were retained by Concanavalin A--Sepharose columns and eluted by alpha methyl-D-mannoside, suggesting by analogy with model complexes that the antigens might be glycoproteins.

Topics: Adsorption; Antibodies, Heterophile; Antigen-Antibody Complex; Antigens, Heterophile; Burkitt Lymphoma; Cell Line; Centrifugation, Density Gradient; Chromatography, Affinity; Complement C3; Complement System Proteins; Concanavalin A; Hemolytic Plaque Technique; Humans; Immunoglobulin G; Male; Nasopharyngeal Neoplasms; Rheumatoid Factor; Sepharose

Topics: Acrylamides; Antigens, Neoplasm; Burkitt Lymphoma; Complement Fixation Tests; Electrophoresis, Disc; Macromolecular Substances; Sepharose