concanavalin-a and Thymus-Neoplasms

In this paper, the effect of the synthetic kappa-opioid agonist (-)U50,488 on 45Ca2- transport into R1.1 mouse thymoma cells is presented. This thymoma cell line expresses selectively the kappa-opioid class of receptors. 45Ca2+ transport into R1.1 cells was not affected by the kappa-opioid agonist (-)U50,488 (10(-10) M-10(-4) M) alone, or in the presence of the plant lectins: PHA (250 microg/ml) and Con A (800 microg/ml), after a 60 min treatment. The plant lectins PHA and Con A stimulated 45Ca2+ transport into R1.1 cells, in high concentrations (100-800 microg/ml) and (200-1000 microg/ml) respectively, after a 60 min treatment. Thus, 45Ca2+ transport was not affected in R1.1 cells by the kappa-opioid agonist (-)U50,488 alone, or in the presence of mitogens after a 60 min treatment. This negative result does not indicate the lack of calcium channels on R1.1 cells, since the plant lectins PHA and Con A were able to stimulate 45Ca2+ transport into R1.1 cells.

Topics: 3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; Animals; Calcium; Concanavalin A; Ion Transport; Mice; Phytohemagglutinins; Receptors, Opioid, kappa; Thymoma; Thymus Neoplasms; Tumor Cells, Cultured

Human thymoma, which is occasionally associated with autoimmune disease, is a thymic epithelial cell tumor and often contains a large number of lymphocytes. In a previous study, we have shown that a proportion of CD4 single positive T cells in human thymomas lack CD3, suggesting immaturity. In this study, we focused on the rest of the CD4 single positive T cells in thymomas that expressed CD3/TcR alpha beta and investigated the maturity of single positive T cells by analyzing lymphocyte surface antigens and the cells' proliferative response to a mitogen. CD4 single positive cells that expressed CD3 or TcR alpha beta also expressed CD69 and had probably undergone positive selection in the tumor. Further, isolated CD4 or CD8 single positive cells from the thymomas responsed to a mitogen although at lower levels than the corresponding single positive cells in the peripheral blood. These results indicate that thymomas contain single positive T cells which have mature phenotype and proliferative ability, and suggest that T cells may differentiate in thymoma.

Topics: Adult; Aged; Antigens, CD; Antigens, Differentiation, T-Lymphocyte; CD3 Complex; CD4-Positive T-Lymphocytes; CD8-Positive T-Lymphocytes; Cell Differentiation; Concanavalin A; Female; Flow Cytometry; Humans; Immunomagnetic Separation; Infant; Lectins, C-Type; Male; Middle Aged; Receptors, Antigen, T-Cell, alpha-beta; T-Lymphocyte Subsets; T-Lymphocytes; Thymoma; Thymus Neoplasms

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a hematopoietic growth factor (HGF) that regulates the proliferation and differentiation of cells of the myeloid lineage. It can be produced by a variety of cells. One of the major sources of GM-CSF is activated T cells, which transiently produce this HGF. We used the EL-4 thymoma cell line as a model system to address the molecular basis for GM-CSF regulation in T cells. Both concanavalin A (ConA) and the phorbol ester, 12-O-tetradecanoylphorbol 13-acetate (TPA) induce GM-CSF expression in EL-4 cells. However, the biological activity of GM-CSF in the supernatants of the TPA-stimulated cells was higher than that of ConA-stimulated cells. To elucidate this difference in biological activity levels, we examined how ConA regulates GM-CSF gene expression in EL-4 cells and compared it to the better-characterized regulation by TPA. Peak mRNA levels of GM-CSF occur 6 h after stimulation with either of these two agents. GM-CSF mRNA levels after ConA treatment are lower and decrease significantly after 10 h compared to TPA treatment, which causes much higher levels that persist for at least 24 h. Neither agent alters GM-CSF gene transcription. Actinomycin D chase experiments show that ConA increases the GM-CSF mRNA half-life from less than 30 to 90 min, whereas TPA prolongs it to greater than 3 h. These results indicate that GM-CSF mRNA induction by ConA (in common with TPA) is regulated predominantly via RNA stabilization and that the difference in prolongation of the mRNA half-life provides the primary explanation for the lower levels of GM-CSF mRNA induced by ConA compared to TPA.

Topics: Animals; Concanavalin A; Dactinomycin; Dose-Response Relationship, Drug; Gene Expression Regulation, Neoplastic; Granulocyte-Macrophage Colony-Stimulating Factor; Half-Life; Mice; RNA Processing, Post-Transcriptional; RNA, Messenger; RNA, Neoplasm; T-Lymphocytes; Tetradecanoylphorbol Acetate; Thymoma; Thymus Neoplasms; Transcription, Genetic; Tumor Cells, Cultured

The effect of human colostrum on T cell immune function was investigated. Colostrum inhibited the proliferation of human T cells activated by allogeneic, concanavalin A (Con A) or phytohaemagglutinin (PHA) stimulation. Colostrum also inhibited the production of IL-2 by Con A-activated human peripheral blood T cells and by Con A-activated Jurkat cells, a human T lymphoma line. Similarly, human colostrum inhibited the production of IL-2 by EL4 cells, a murine thymoma line, when stimulated with phorbol myristate acetate. The inhibitory activity was not cytotoxic and could not be neutralized by antibody to transforming human growth factor beta.

Topics: Cell Survival; Colostrum; Concanavalin A; Dose-Response Relationship, Drug; Humans; Interleukin-2; Lectins; Lymphocyte Activation; Lymphocyte Culture Test, Mixed; Lymphoma, T-Cell; Phytohemagglutinins; T-Lymphocytes; Tetradecanoylphorbol Acetate; Thymoma; Thymus Neoplasms; Transforming Growth Factor beta

Functional receptors for insulin-like growth factors (IGF) I and II have been identified in rat thymocytes and mouse thymoma cell lines R1.1 and S49.1. IGF-I receptor alpha-subunit (MW 130,000) bind IGF-I and IGF-II with equal affinity (Kd approximately 4-7 nM), and insulin with approximately 100 times lower affinity. Tyrosine kinase activity and autophosphorylation of the IGF-I receptor beta-subunit (MW 95,000) are stimulated by IGF-I and IGF-II with equal potency (ED50 approximately 0.5 nM). IGF-II receptors (MW 250,000) bind IGF-II with Kd approximately 0.3 nM and IGF-I with 30 times lower affinity, but not insulin. IGF-I and IGF-II do not cross-react with the insulin receptor to which insulin binds with an apparent Kd approximately 1 nM, and stimulates its tyrosine kinase activity with ED50 approximately 3 nM. In thymocytes, alpha-aminoisobutyric acid transport is stimulated 2-fold by IGF-I and IGF-II with identical potency (ED50 approximately 2 nM), and by insulin with ED50 approximately 10 nM. Activation of thymocytes by concanavalin A increased the number of IGF-II receptors 2-fold, whereas IGF-I receptor binding and IGF-stimulated amino acid transport were unaltered. We conclude that the effect of IGF-I and IGF-II in thymocytes is mediated via binding to the IGF-I receptor and stimulation of its tyrosine kinase. The presence of functional IGF receptors on thymocytes and thymoma cells suggests that IGF-I and IGF-II play a role in the regulation of thymic functions.

Topics: Affinity Labels; Amino Acids; Animals; Cell Line; Concanavalin A; Female; Male; Mice; Protein-Tyrosine Kinases; Rats; Rats, Inbred Strains; Receptors, Cell Surface; Receptors, Somatomedin; Thymoma; Thymus Gland; Thymus Neoplasms

The ability of EL-4 thymoma cells to produce interleukin-2 (IL-2) following exposure to phorbol-12-myristate 13-acetate (PMA) and Concanavalin A (Con A) has been studied in vitro using medium containing either 10% or 1% fetal calf serum (FCS). The potent stimulatory effect of PMA on IL-2 production by EL-4 cells has been confirmed by measuring 3H-thymidine incorporation by the IL-2-dependent T cell line, CTLL-2, in the presence of conditioned medium (CM) from stimulated cultures. EL-4 cells produced several times more IL-2 when cultured in medium containing 10% FCS than when only 1% FCS was present. Added together, PMA and Con A acted synergistically in some EL-4 cell cultures. The ability of E:-4 cells to produce IL-2 was maintained after further incubation without stimulants. CM with IL-2 activity from stimulated EL-4 cells could prove useful in immunotoxicity testing.

Topics: Animals; Cell Division; Concanavalin A; Cytotoxicity Tests, Immunologic; Interleukin-2; Mice; Spleen; T-Lymphocytes, Cytotoxic; Tetradecanoylphorbol Acetate; Thymidine; Thymoma; Thymus Neoplasms; Tritium; Tumor Cells, Cultured

In order to obtain a better understanding of the immunological abnormalities present in myasthenia gravis (MG), which is often accompanied by thymoma or thymic hyperplasia, we investigated lymphocyte subsets and their functions using samples of thymoma or thymic hyperplasia tissues from 11 patients (6 cases with MG), and peripheral blood from 6 patients (4 cases with MG). In most thymic tissues from patients with MG, a maturating tendency of lymphocytes was generally observed. Especially in the medulla of thymic hyperplasia, an entirely peripheral blood type of T-lymphocytes, which were Leu-6- and either Leu-2a+ or 3a + 3b+, were encountered abundantly. Therefore, the presence of abnormal maturation of lymphocytes in the thymus or destruction of the barrier between the thymus and the peripheral blood in MG cases was indicated. In cases without MG, no such tendency was noted. As to the peripheral blood in patients with MG, concanavalin A-induced suppressor cells were significantly decreased (p less than 0.01). All of these changes were considered to be intimately related to the appearance of MG.

Topics: Adult; Aged; Antigens, Differentiation, T-Lymphocyte; Child; Concanavalin A; Female; Humans; Immunohistochemistry; Male; Middle Aged; Myasthenia Gravis; T-Lymphocytes; Thymoma; Thymus Gland; Thymus Neoplasms

We have examined the localization of phospholipid/calcium-dependent protein kinase (protein kinase C) in thymoma cells, which were resected from a patient with myasthenia gravis. Upon stimulation with 4 micrograms/ml of concanavalin A (Con A) for 30 min, protein kinase C activity in the cytosolic fraction was increased from 7.44 pmol/min per 10(7) cells to 11.42 pmol/min per 10(7) cells. On the other hand, membrane-associated protein kinase C activity was decreased from 1.69 to 0.71 pmol/min per 10(7) cells. On the contrary, 10(-7) mol/l tetradecanoyl phorbol acetate (TPA) decreased cytosolic protein kinase C activity from 9.31 to 8.04 pmol/min per 10(7) cells, while membrane-associated protein kinase C activity was increased from 1.69 to 2.94 pmol/min per 10(7) cells. Several endogenous phosphorylated proteins (mol wt 20,000, 23,000) were observed as inferred by SDS-polyacrylamide gel electrophoresis. These findings indicated that Con A and TPA produce differential translocation of protein kinase C.

Topics: Concanavalin A; Cytosol; Electrophoresis, Polyacrylamide Gel; Female; Humans; Middle Aged; Myasthenia Gravis; Phorbol Esters; Phosphorylation; Protein Kinase C; Subcellular Fractions; Thymoma; Thymus Neoplasms

Sendai virus vesicles were used as vehicles for the insertion of various cell membranes into different cell lines. The transplantation efficiency was measured by using FITC-labelled concanavalin A (Con A) or monoclonal antibodies against the T-cell marker Lyt 2 and the major histocompatibility complex product H-2Db in a fluorescence-activated cell sorter. Results indicate that it is possible to transplant mitogen responsiveness to certain cell types. Con A stimulation of T-cell membrane transplanted BW 5147 showed that it is possible to induce a mitogen dose-dependent T-cell growth factor production. Consequently this method appears to be an attractive model for further study of the properties of the membrane structures involved in mitogen triggering of cells.

Topics: Animals; Cell Fusion; Cell Line; Cell Membrane; Concanavalin A; Dose-Response Relationship, Immunologic; Interleukin-2; Leukemia L1210; Lymphocyte Activation; Lymphoma; Mice; Mice, Inbred AKR; Mice, Inbred C57BL; Mice, Inbred DBA; Receptors, Antigen, T-Cell; Receptors, Concanavalin A; T-Lymphocytes; Thymus Neoplasms

In this report we show that three mutagenized sublines of (murine) EL-4 thymoma cells can constitutively activate human and/or murine B cells via an MHC-nonrestricted cell-cell interaction. The activation signal is not by itself mitogenic but renders B cells capable of proliferating in response to interleukin 2 (IL 2). In addition, one of the mutant EL-4 sublines can constitutively respond by release of IL 2 in the presence of IL 1-containing macrophage (P388D1) supernatant. The exact relationships between these functional properties of the mutant EL-4 thymoma cells and those associated with activated normal T helper-cells remain to be established. However, the EL-4 cells provide a unique system to study in parallel murine and human B cell responses. In particular, the following observations were made during the present study. First, anti-Ig antibodies (anti-Ig) were required for B cell activation in conjunction with two EL-4 sublines acting only on murine B cells, whereas with a third subline acting on both murine and human B cells, anti-Ig was not required. Anti-Ig by itself did not lead to significant B cell activation in the absence of mutant EL-4 (or normal T) cells. Second, the growth factor-stimulated proliferation of EL-4-activated B cells, following separation of the B cells from the EL-4 cells, lasted only 2 days. These results, thus, indicate that the requirement for a surface Ig-mediated B cell activation signal depends on the quality/intensity of a direct T cell signal and that cell-cell interactions may exert a more stringent control over the growth factor responsiveness of B cells as compared with T cells.

Topics: Animals; Antibodies, Anti-Idiotypic; B-Lymphocytes; Cell Line; Concanavalin A; Hemolytic Plaque Technique; Humans; Interleukin-2; Kinetics; Lymphocyte Activation; Lymphocyte Cooperation; Lymphokines; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mutation; T-Lymphocytes; Thymoma; Thymus Neoplasms

The capacity of several types of cell preparations to induce in vivo a state of memory for a secondary in vitro cytotoxic response against non-major-histocompatibility antigen was markedly reduced (on a per cell basis) by uv-irradiation. This indicated that memory induction requires metabolically active stimulator cells. An "adherent cell preparation" (AC) that was enriched for dendritic cells was among the most effective memory-inducing cell populations; but concanavalin A-activated nylon-wool-nonadherent spleen cells (Con A-NWT) or concanavalin A-activated unfractionated spleen cells (Con A-spl) were on the average equally effective. Normal unfractionated spleen cells (spl) or nonactivated nylon-wool-nonadherent cells (NWT) were markedly less effective on a per cell basis. This pattern of stimulatory activity was in line with the relative stimulatory activity of these cell types in primary cytotoxic responses in the presence of interleukin 2 (IL-2) and also in line with the relative capacity to induce IL-2-dependent proliferation in H-2D-incompatible T-cell populations (cf. W. Dröge et al., J. Immunol. 132, 2749, 1984). These differences in the immunogenic potential and the requirement for metabolically active stimulator cells suggested that these cells stimulated the CTL system directly and not indirectly through antigen processing cells of the immunized host. Nevertheless, the secondary cytotoxic response after injection of low numbers of Con A-spl into H-2 heterozygous recipients, (BALB/c X BALB/b)F1, or into recipients with recombinant H-2 haplotype (A.J) was only preferentially but not exclusively restricted to the H-2 haplotype of the immunizing cell populations. Restriction was considerably more complete when AC were used for immunization.

Topics: Animals; Cell Line; Concanavalin A; Cytotoxicity, Immunologic; Histocompatibility Antigens; Immunologic Memory; Interleukin-2; Lymphocyte Activation; Mice; Mice, Inbred Strains; Species Specificity; Spleen; T-Lymphocytes, Cytotoxic; Thymoma; Thymus Neoplasms

Conditioned medium from mouse T lymphoma BW 5147 cell cultures suppressed Con A-stimulated DNA synthesis in cultures of mouse spleen cells. Supernatants from control mouse T cell lymphoma EL-4 were not effective. Conditioned medium from BW 5147 cells did not inhibit DNA synthesis in control cultures of IL-2-dependent mouse T cells or mouse leukaemias of T cell or erythroblastic origin. It is suggested that constitutive production of a soluble suppressor factor by BW 5147 lymphoma cells is responsible for the effects observed.

Topics: Animals; Cell Line; Cells, Cultured; Concanavalin A; Immune Tolerance; Lymphocyte Activation; Mice; Spleen; Thymoma; Thymus Neoplasms

Requirements for stimulation of cytotoxic T cells (CTL) and for their lytic recognition have been compared in T cell lines repeatedly stimulated with trinitrobenzene sulfonate-treated syngeneic murine spleen cells. Differences were observed between the requirements for cells to stimulate or to be lysed by the CTL, which included: (a) the expression of major histocompatibility complex (MHC = H-2) encoded allelic products, and (b) the hapten density. Propagation of the CTL within the line required I-A intra-H-2 homology between hapten-treated stimulation cells and the line cells, whereas the lytic interaction required H-2K region homology between hapten-treated target cells and CTL. The hapten density requirement was analyzed for a responder (H-2k) and a non-responder (H-2b) strain to low hapten density modified syngeneic cells. This property was found to be a characteristic of the lytic phase rather than of the stimulation of CTL. CTL clones could be derived by growing the line cells under conditions of limiting dilution in the presence ot T cell growth factors. Such CTL clones were unable to be stimulated by their target antigens and were dependent on T cell growth factors for their propagation. These results are discussed in terms of the dependence of the development and growth of CTL on T helper cells.

Topics: Animals; Cell Division; Cell Line; Concanavalin A; Crosses, Genetic; Cytotoxicity, Immunologic; Haptens; Lymphocyte Activation; Major Histocompatibility Complex; Mice; Mice, Inbred Strains; Neoplasms, Experimental; T-Lymphocytes; Thymoma; Thymus Neoplasms

Phorbol-12-myristate-13-acetate stimulates a subline of mouse EL-4 thymoma cells to produce, in vitro, in very high titer, T cell growth factor (Interleukin 2, IL 2). The EL-4-derived IL 2 has the same m.w. (30,000) and isoelectric point heterogeneity (pI 3.8-4.4) as the IL 2 produced by Con A-stimulated spleen cells. In addition, the thymoma-derived IL 2 exhibits the same spectrum of biologic activities as has been reported for spleen cell-derived IL 2.

Topics: Animals; Chromatography, Gel; Concanavalin A; Growth Substances; Interleukin-2; Lymphokines; Mice; Molecular Weight; T-Lymphocytes; Tetradecanoylphorbol Acetate; Thymoma; Thymus Neoplasms

In the present work the in vitro response to PHA and ConA was determined for thymus lymphocytes from normal, hyperplastic, and neoplastic conditions as well as for peripheral blood lymphocytes from normal control donors. Our investigation has revealed these results: (1) lymphocytes from normal thymus are less responsive to both mitogens than lymphocytes from peripheral blood and abnormal thymus. (2) Lymphocytes from thymic benign lymphoid hyperplasia show an increased response only to PHA regardless of the extent of hyperplasia. (3) Lymphocytes from thymic neoplasia display an increased response to both mitogens regardless of the histologic pattern of the tumor studied. (4) Thymic lymphocytes from patients with myasthenia gravis have a mitogenic response higher than that from thymic lymphocytes from nonmyasthenic subjects. (5) In patients with myasthenia gravis, lymphocytes from neoplastic thymus show a response to PHA higher than that observed for lymphocytes from hyperplastic thymus. It seems clear that two conditions maximally enhance mitogenic response of thymus lymphocytes: thymomas and myasthenia.

Topics: Adolescent; Adult; Aged; Child; Concanavalin A; Female; Humans; Lymphocyte Activation; Male; Middle Aged; Phytohemagglutinins; Thymoma; Thymus Gland; Thymus Hyperplasia; Thymus Neoplasms

Mitogen-induced blast transformation of peripheral blood lymphocytes and quantitative changes in circulating T- and B-cells were studied serially in cats inoculated with feline leukemia virus (FeLV). Concanavalin A-induced blast transformation sharply declined beginning at 5 weeks post inoculation (Pl) in FeLV-infected cats when compared to age-matched uninfected control cats. Similar but less consistent changes were seen in responses to pokeweed mitogen-induced stimulation. In most infected kittens this defect persisted until they died from thymic lymphosarcoma, 15-24 weeks Pl. An early lymphopenia, due primarily to a decrease in circulating B-cells, occurred in infected cats 5-8 weeks Pl. Following a return of total and B-lymphocytes to control values, infected cats developed increased numbers of T-cells at 16 or more weeks Pl, which correlated with circulating lymphoblastic lymphocytes bearing T-cell markers. These results correlated neoplasia arising in a thymus-derived lymphocyte population with mitogenic hyporeactivity in the preneoplastic period and suggested that FeLV-induced immune alterations may be a necessary antecedent of leukemogenesis in the cat.

Topics: Animals; B-Lymphocytes; Cats; Concanavalin A; Erythrocytes; Immunosuppression Therapy; Leukemia Virus, Feline; Leukemia, Experimental; Leukocyte Count; Lymphocyte Activation; Lymphoma, Non-Hodgkin; Mitogens; Neoplasms, Experimental; T-Lymphocytes; Thymus Neoplasms

Topics: Animals; Concanavalin A; DNA; Lectins; Leukemia L1210; Lymphoma; Mice; Neoplasm Transplantation; Neoplasms, Experimental; Thymidine; Thymus Neoplasms