concanavalin-a and Thymoma

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

IL-1 receptor heterogeneity in murine lymphocytes was investigated by cross-linking to [125I]IL-1 alpha and competition with IL-1 receptor antagonist, and the molecular identity of the IL-1 receptors was identified with PCR using primers specific for type I and type II IL-1 receptors. The thymoma cell line E14 6.1 exhibits exclusively the 80 kDa receptors which proved to be the type I receptor according to PCR analysis. In the pre-B cell line 70Z/3, predominantly a 60 kDa type II receptor but also a trace of type I receptor can be identified by PCR. The Th2 cell line D10N expresses both types of IL-1 receptors in equivalent amounts according to cross-linking experiments and PCR. The proliferative response of D10N cells to IL-1 is inhibited by IL-1 ra which according to cross-linking affects the binding to the type I receptor only. It is concluded that coexpression of both types of IL-1 receptors might be a characteristic of murine Th2 cells and that their growth-dependence on IL-1 is mediated by the type I receptor.

Topics: Amino Acid Sequence; Animals; Base Sequence; Binding, Competitive; Cell Division; Cell Line; Concanavalin A; Cross-Linking Reagents; DNA; Gene Expression; Interleukin-1; Mice; Molecular Sequence Data; Polymerase Chain Reaction; Receptors, Interleukin-1; RNA; T-Lymphocytes, Helper-Inducer; Thymoma; Tumor Cells, Cultured

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

Phorbol esters (TPA) and concanavalin A (ConA) are known to induce granulocyte-macrophage colony-stimulating factor (GM-CSF) production in murine thymoma EL-4 cells by mRNA stabilization. The role of the 3'-untranslated region (3'-UTR) in GM-CSF mRNA stabilization induced by TPA and ConA in EL-4 cells was examined by transfection studies using chloramphenicol acetyltransferase (CAT) constructions. The GM-CSF 3'-UTR contains a 63-nucleotide region at its 3' end with repeating ATTTA motifs which is responsible for mRNA degradation in a variety of cell types (Shaw, G., and Kamen, R. (1986) Cell 46, 659-666). We produced constructs containing most of the GM-CSF 3'-UTR (303 nucleotides, pRSV-CATgm) or the 3'-terminal AT-rich region (116 nucleotides, pRSV-CATau) and measured CAT enzyme activity and CAT mRNA after transient transfection into EL-4 and NIH 3T3 cells. Low levels of CAT activity were seen in both cells with either plasmid compared with levels of CAT activity obtained with pRSV-CAT. TPA treatment caused an approximately 10-fold increase in CAT activity and mRNA in EL-4 cells transfected with pRSV-CATgm. No increases were seen in EL-4 cells transfected with pRSV-CATau or pRSV-CAT. No response to TPA was detected in transfected NIH 3T3 cells, indicating that the response to TPA is relatively cell-specific. There was no increase in CAT activity after ConA treatment in EL-4 or NIH 3T3 cells transfected with any of the constructs suggesting that the GM-CSF 3'-UTR lacks elements that can respond alone to ConA. Nuclear run-on and actinomycin D chase experiments in EL-4 cells showed that TPA induces CAT activity via mRNA stabilization. By linker-substitution mutagenesis we show that TPA inducibility depends on a 60-nucleotide region of the 3'-UTR whose 5' end is located 160 nucleotides upstream of the 5' end of the AU-rich region.

Topics: Animals; Base Sequence; Blotting, Northern; Chloramphenicol O-Acetyltransferase; Concanavalin A; DNA, Neoplasm; Granulocyte-Macrophage Colony-Stimulating Factor; Mice; Mitogens; Molecular Sequence Data; Mutagenesis; Plasmids; Protein Biosynthesis; RNA, Messenger; RNA, Neoplasm; Tetradecanoylphorbol Acetate; Thymoma; Transcription, Genetic; Transfection

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

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

Fluorescein-specific cytolytic hybrids were obtained by fusion of an interleukin 2 (IL2)-dependent murine cytotoxic T lymphocyte clone with the thymoma BW5147. The hybrid cells grow and retain cytolytic activity in medium with recombinant IL2. In medium without IL2 rare variants can be selected which grow in the absence of exogenous IL2; these variants are not cytolytic. Anti-IL2 receptor antibodies bind to and inhibit the growth of the cytolytic hybrids while they do not bind to and do not inhibit the growth of the variants. The cytolytic hybrids as well as the non-cytolytic variants produce interferon gamma in response to antigen. These findings indicate that the noncytolytic IL2-dependent variants lost IL2 receptors but not antigen receptors.

Topics: Animals; Concanavalin A; Genetic Variation; Hybridomas; Interferon-gamma; Interleukin-2; Mice; Mice, Inbred CBA; Receptors, Immunologic; Receptors, Interleukin-2; T-Lymphocytes, Cytotoxic; Thymoma

The signal requirement for polyclonal B cell responses in the presence of T helper (Th) cells, lipopolysaccharide (LPS), anti-Ig antibodies coupled to Sepharose beads (anti-Ig) and/or T cell supernatants (SN) was studied in a murine system using (a) low numbers of B cells/culture in order to reduce the effects of contaminating Th cells and (b) defined sources of irradiated filler cells in the form of EL4 thymoma cells or cloned male H-Y antigen-specific Th cells. The results demonstrate that for optimal proliferation as well as (protein A) plaque-forming cell (PFC) generation B cells required at least two activation signals in addition to factor(s) present in Th or EL4 SN, i.e. either a specific (or concanavalin A-dependent nonspecific) Th signal and anti-Ig or (in cultures with EL4 filler cells) LPS and anti-Ig. While confirming several previous studies, including our own, which showed a requirement for two activation signals in conjunction with T cell factors in antigen-specific B cell responses, the present system differs from previous polyclonal systems by showing nonoverlapping effects of LPS or a specific Th signal on the one hand and anti-Ig on the other in the induction of growth factor responsiveness of B cells. In addition, limiting dilution analysis showed that in cultures with EL4 filler cells, LPS, anti-Ig and EL4 SN 1/8 surface Ig-positive cells generated greater than 10 PFC with a mean clone size of 70 PFC and indicated that only the B cells were limiting. This system using defined thymoma filler cells should be useful for assaying factors potentially replacing the LPS or anti-Ig signals.

Topics: Animals; Antibodies, Anti-Idiotypic; Antibody Formation; Antibody-Producing Cells; B-Lymphocytes; Cell Division; Concanavalin A; Immunoglobulin A; Lipopolysaccharides; Mice; Mice, Inbred C57BL; T-Lymphocytes, Helper-Inducer; Thymoma

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

We have employed bifunctional T cell hybridomas, which can be stimulated to secrete lymphokine(s) and lyse specific target cells, to analyze the effect of Cyclosporin A (CsA) on T cell helper and effector functions. We report here the effects of CsA on antigen- and lectin-induced lymphokine secretion. We have found that a pharmacologic level of CsA (10 ng/ml) blocks antigen- and lectin-driven interleukin 2 (IL 2) secretion without affecting cell proliferation. In addition, one monoclonal hybridoma that is induced by concanavalin A to secrete colony stimulating factors (CSF) as well as IL 2 is concomitantly blocked by CsA for production of IL 2 and CSF. Because the hybridomas grow constitutively and are devoid of functional IL 2 receptors, they permit analysis of the kinetics of the inhibitory response. We have shown that CsA blocks not only stimulation of lymphokine secretion but also ongoing IL 2 production, probably by interfering with the effective interaction of receptor and antigen. Thus, blocking of IL 2 secretion from preactivated cells by CsA occurs by 1 to 2 hr, the time required to stop IL 2 production by removal of Ag/Lectin stimulator. The results are consistent with a mechanism of action of CsA on T cells that involves a direct interference of CsA with binding of Ag to Ag-receptor and results in blocking of induction and active secretion of multiple lymphokines.

Topics: Animals; Antigens, Neoplasm; Binding, Competitive; Colony-Stimulating Factors; Concanavalin A; Cyclosporins; Hybridomas; Interleukin-2; Lymphocyte Activation; Mice; Mice, Inbred BALB C; Receptors, Immunologic; Receptors, Interleukin-2; T-Lymphocytes; Thymoma

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

The combination of two-dimensional gel electrophoresis and post-electrophoretic staining with 125I-labelled concanavalin A was used to compare the glycoproteins of murine tumour cell lines. Comparison between different cell lines showed that there were about eight common glycoproteins. The rest of the glycoproteins were generally unique to particular cells. Thus the P815 cell could be distinguished from 13 other murine cell lines by its glycoprotein pattern. The specific glycoproteins of each cell line were unaffected by culture in vivo, virus infection or hybridisation. Different clones from the same cell line gave identical patterns. Crude membrane preparations and glycoproteins purified from cell lysates by affinity chromatography on concanavalin/agarose gave the same patterns as whole cells. Thus the glycoproteins of murine tumour cells appear to be a stable characteristic which can provide specific markers for the identification of tumour cell lines.

Topics: Animals; Cell Line; Concanavalin A; Electrophoresis; Glycoproteins; Iodine Radioisotopes; Isotope Labeling; Mast-Cell Sarcoma; Mice; Neoplasm Proteins; Neoplasms, Experimental; Thymoma

Two growth factors, interleukin 2 (T cell growth factor) and colony-stimulating factor, are produced concomitantly by a murine EL-4 thymoma cell line after stimulation by phorbol myristate acetate. As shown elsewhere, these thymoma-derived factors appear to be biochemically and functionally indistinguishable from the interleukin 2 and colony-stimulating factor produced by mitogen-stimulated mouse spleen cells. Both factors co-elute during gel filtration with apparent m.w. in the range of 30,000, and both exhibit overlapping isoelectric point profiles between pH 4 and pH 5. Because we were unable to separate these 2 factors by methods based on either m.w. or charge, we have used phenyl-Sepharose chromatography, a method based on hydrophobic interactions, to completely separate murine interleukin 2 and colony-stimulating factor. In contrast with published reports, each of the separated factors exhibits unique biologic activities on lymphocytes and macrophages. Interleukin 2 provides help for antibody synthesis in the nude mouse, but neither enhances interferon production by macrophages nor stimulates macrophage growth. Colony-stimulating factor does not enhance antibody synthesis in the nude mouse but does enhance interferon production by macrophages and stimulate macrophage growth.

Topics: Animals; Antibody Formation; Chromatography; Chromatography, Agarose; Chromatography, Gel; Colony-Stimulating Factors; Concanavalin A; Interferons; Interleukin-2; Lymphokines; Mice; Mice, Inbred C3H; Mice, Inbred C57BL; Mice, Nude; Molecular Weight; Tetradecanoylphorbol Acetate; Thymoma

The existence of suppressor mononuclear cells were demonstrated in two lymphoproliferative disorders: giant lymph node hyperplasia and thymona. The three patients tested also showed cell-mediated immunodeficiency as expressed in the low number of T cells, negative graft versus host reactions and negative skin tests; the one patient tested with phytohemagglutinin (PHA) and concavalin A (Con A) showed a low response. Suppressor activity was tested with a new experimental model, the local xenogeneic graft versus host reaction. It is proposed that this model be used for testing suppressor activities in other human disorders as well.

Topics: Adolescent; Animals; Child; Child, Preschool; Concanavalin A; Female; Graft vs Host Reaction; Hamartoma; Humans; Hyperplasia; Lymph Nodes; Lymphocyte Activation; Male; Models, Biological; Monocytes; Phytohemagglutinins; Rats; Skin Tests; T-Lymphocytes, Regulatory; Thymoma

Topics: Animals; Cell Cycle; Cell Line; Concanavalin A; Dose-Response Relationship, Immunologic; Humans; Interleukin-2; Lymphocyte Activation; Lymphokines; Mice; Mice, Inbred Strains; Mitogens; Phagocytes; T-Lymphocytes; Tetradecanoylphorbol Acetate; Thymoma

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