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Biomedical subjects

M B Prystowsky

Publications and source records attributed to M B Prystowsky.

At least 91 records · Page 5Linked to original sources
PubMed1987

Preproenkephalin mRNA in T-cells, macrophages, and mast cells.

The presence of preproenkephalin mRNA in tumor cell lines derived from myeloid and mast cells was analyzed by RNA dot blot hybridization. A B-cell lymphoma was negative for preproenkephalin mRNA, but several T-cell lymphomas were positive. A mastocytoma and two macrophage cell lines were found to have high levels of preproenkephalin mRNA. Purified natural macrophages and mast cells also possessed easily detectable levels of this mRNA.

Animals↗
PubMed1987

Isolation and initial characterization of multiple species of T-lymphocyte subset cDNA clones.

A modified differential screening procedure was applied to analyze cDNA libraries of cloned helper T lymphocytes (Th) and cytolytic T lymphocytes (CTL). Negative and positive differential screening and RNA blot analysis were used to identify cDNA clones that were expressed preferentially in Th or CTL. Seven clones corresponded to previously described T-cell genes, and 16 additional types of cDNA clones were isolated, 9 from Th and 7 from CTL. Of these, 3 were expressed in both Th and CTL, 7 were expressed in only Th, and 6 only in CTL. These clones were analyzed for induction after stimulation by interleukin 2 or Con A or after stimulation of the T-cell antigen receptor (TCR). Three different patterns of expression were seen: induction only by Con A, induction by Con A and interleukin 2, and induction by Con A and TCR stimulation. The approach is potentially useful for analyzing paths of T-cell differentiation and detecting cDNA clones encoding unrecognized cytokines.

Animals↗
PubMed1987

Proto-oncogene expression in cloned T lymphocytes: mitogens and growth factors induce different patterns of expression.

We have compared the effects of a mitogenic lectin, concanavalin A (Con A), and a growth factor, interleukin-2 (IL-2), on the expression of the c-myc, c-fos, and c-myb proto-oncogenes in cloned T lymphocytes. Accumulation of c-myc mRNA was induced by both ConA and IL-2 in these cells. In contrast, expression of c-fos was stimulated primarily by ConA, and accumulation of c-myb mRNA was induced predominantly by IL-2. Thus, ConA and IL-2 induce expression of overlapping, but non-identical, sets of proto-oncogenes in T lymphocytes. Investigations with several different cloned T cells revealed that: (1) c-myb is not induced in all T cells stimulated to grow, indicating that its expression may not be absolutely required for their proliferation; and (2) expression of c-myc, even in combination with c-fos, can be insufficient for growth, demonstrating functional differences between cellular and viral oncogenes in T cells. These observations provide insight into the roles of the c-myc, c-fos, and c-myb proto-oncogenes in normal T cell responses.

Cell Division↗
PubMed1986

Cloned helper T lymphocytes exposed to interleukin 2 become unresponsive to antigen and concanavalin A but not to calcium ionophore and phorbol ester.

Two cloned murine helper T lymphocyte (HTL) lines were used to investigate the immunoregulatory properties of highly purified interleukin 2 (IL2). The clone, designated J6.19, secretes lymphokines, including IL2, and proliferates when stimulated with ovalbumin in the presence of I-Ak-bearing spleen cells, while the alloreactive clone, L2, secretes lymphokines, including IL2, and proliferates when stimulated with Mlsa,d-bearing spleen cells. When either clone was exposed to a high concentration of pure IL2 for 1 to 2 days in the absence of either antigen or spleen cells, the HTL became unresponsive to rechallenge with antigen. Unresponsiveness to antigen was indicated by an inability of HTL to proliferate or secrete usual amounts of IL2 or colony-stimulating factor. Within 5-7 days after exposure to IL2, the cloned HTL again responded to antigen. Thus, in addition to being a growth factor for HTL, IL2 can limit the magnitude of the HTL response to antigen. L2 or J6.19 cells could also be induced to secrete lymphokines by the lectin, concanavalin A (Con A) or by a combination of the calcium ionophore, A23187, and phorbol myristate acetate (PMA). After exposure of L2 or J6.19 cells to sufficient IL2 to induce unresponsiveness to antigen, cells were also unresponsive to Con A, as indicated by a reduction in the level of lymphokines secreted. In contrast, lymphokine levels stimulated by A23187/PMA were comparable to those produced by cells not exposed to IL2. The failure of antigen to stimulate lymphokine release and proliferation by HTL previously exposed to IL2 therefore may result from an inability of HTL to recognize antigen or to transduce effectively the antigen recognition signal. Several T cell surface molecules are known to be involved in antigen activation of HTL; these include the antigen receptor and the "associative recognition" structures L3T4 and LFA-1. We observed that L2 cells, rendered unresponsive to antigen by exposure to IL2, expressed normal levels of antigen receptor, as identified by the monoclonal antibody, KJ16-133.18. Furthermore, expression of L3T4 and LFA-1 was not decreased. Unresponsiveness to antigen induced by IL2 thus could not be correlated with decreases in the expression of antigen receptors, L3T4, or LFA-1. Unresponsive HTL may therefore be capable of recognizing antigen but the signal generated by antigen binding may be attenuated during its transduction, resulting in the failure of cloned HTL to proliferate or secrete lymphokines at the usual levels.

Animals↗
PubMed1986

Cloned T-cell proliferation and synthesis of specific proteins are inhibited by quinine.

Recombinant human interleukin 2 (rIL-2) drives the proliferation of the cloned murine T-helper line L2. The initial G1 activation occurs during the first 20 hr after stimulation, with DNA synthesis (S phase) beginning approximately 20 hr after rIL-2 stimulation. Three patterns of protein synthesis were observed during G1 activation. Type I proteins (e.g., p72 and p66) were synthesized at near maximal rates as early as 4 hr after stimulation, with little change in rates of synthesis through the G1 to S phase transition. Type II proteins (e.g., p52 and p36) were detectable early after stimulation, but their rates of synthesis continued to increase throughout G1 activation, becoming maximal 24-28 hr after stimulation. Type III proteins (e.g., p93, p89, and p63) were synthesized maximally 4 or 8 hr after rIL-2 stimulation, then their rates of synthesis declined markedly to prestimulation levels. Type II proteins, p52 and p36, were shown to be correlated with cell proliferation, since their rates of synthesis were maximal while L2 cells were proliferating and declined as the cells returned to a quiescent state. The potassium channel blocker quinine inhibited cell growth and the synthesis of p52 and p36 when added 0 or 2 hr after rIL-2 stimulation but not when added 6 hr after rIL-2 stimulation. Thus, a quinine-sensitive event occurring in L2 cells between 2 and 6 hr after rIL-2 stimulation is necessary for synthesis of type II proteins, DNA synthesis, and cell proliferation.

Animals↗
PubMed1986

Increased voltage-gated potassium conductance during interleukin 2-stimulated proliferation of a mouse helper T lymphocyte clone.

Recent work has demonstrated the presence of voltage-gated potassium channels in human peripheral blood T lymphocytes (Matteson, R., and C. Deutsch, 1984, Nature (Lond.), 307:468-471; DeCoursey T. E., T. G. Chandy, S. Gupta, and M. D. Cahalan, 1984, Nature (Lond.), 307:465-468) and a murine cytolytic T-cell clone (Fukushima, Y., S. Hagiwara, and M. Henkart, 1984, J. Physiol., 351:645-656). Using the whole cell patch clamp, we have found a potassium conductance with similar properties in a murine noncytolytic T lymphocyte clone, L2. Under voltage clamp, a step from a holding potential of -70 mV to +50 mV produces an average outward current of 100-150 pA in "quiescent" L2 cells at the end of their weekly maintenance cycle. When these cells are stimulated with human recombinant interleukin 2 (rIL2, 100 U/ml), they grow in size and initiate DNA synthesis at approximately 24 h. Potassium conductance is increased as early as 8 h after stimulation with rIL2 and rises to a level 3-4 times that of excipient controls by 24 h. The level remains elevated through 72 h, but as the cells begin to leave the cell cycle at 72-96 h, the conductance decreases quickly to a value only slightly higher than the initial one. Quinine, a blocker of this conductance, markedly reduces the rate at which L2 cells traverse the cell cycle, while also reducing the rate of stimulated protein synthesis. The regulation of potassium conductance in L2 cells during rIL2-stimulated proliferation suggests that potassium channel function may play a role in support of the proliferative response.

Animals↗
PubMed1985

Hairy-cell leukemia associated with Hodgkin's disease: a case report.

A 56-year-old man who had easy bruising, an enlarged left supraclavicular lymph node, and splenomegaly was diagnosed as having hairy-cell leukemia. Treatment consisted of splenectomy. Because of progressive lymphadenopathy in the following months, the patient required reevaluation. Examination of a lymph node biopsy specimen now revealed Hodgkin's disease, nodular sclerosis. This is the first pathologically confirmed case of hairy-cell leukemia coexisting with Hodgkin's disease.

Hodgkin Disease↗
PubMed1985

Recombinant interleukin 2 regulates levels of c-myc mRNA in a cloned murine T lymphocyte.

The cellular oncogene c-myc has been implicated in the regulation of growth of normal and neoplastic cells. Recently, it was suggested that c-myc gene expression may control the G0----G1-phase transition in normal lymphocytes that were stimulated to enter the cell cycle by the lectin concanavalin A (ConA). Here we describe the effects of purified recombinant interleukin 2 (rIL2) and of ConA on levels of c-myc mRNA in the noncytolytic murine T-cell clone L2. In contrast to resting (G0) primary cultures of lymphocytes, quiescent L2 cells have a higher RNA content than resting splenocytes and express receptors for interleukin 2 (IL2). Resting L2 cells are therefore best regarded as early G1-phase cells. Purified rIL2 was found to stimulate the rapid accumulation of c-myc mRNA in L2 cells. Levels of c-myc mRNA became maximal within 1 h and declined gradually thereafter. In contrast, ConA induced slower accumulation of c-myc mRNA in L2 cells, with increased levels of c-myc mRNA becoming detectable 4 to 8 h after stimulation. Experiments with the protein synthesis inhibitor cycloheximide demonstrated that the increase in levels of c-myc mRNA that were induced by ConA was a direct effect of this lectin and not secondary to IL2 production. Cyclosporin A, an immunosuppressive agent, markedly reduced the accumulation of c-myc mRNA that was induced by ConA but only slightly diminished the accumulation of c-myc mRNA that was induced by rIL2. Taken together, these data provide evidence that (i) c-myc gene expression can be regulated by at least two distinct pathways in T lymphocytes, only one of which is sensitive to cyclosporine A, and (ii) the accumulation of c-myc mRNA can be induced in T cells by IL2 during the G1 phase of the cell cycle.

Animals↗
PubMed1984

Mouse T cell antigen receptor: structure and organization of constant and joining gene segments encoding the beta polypeptide.

The germ-line joining (J) gene segments and constant (C) genes encoding the beta chain of the mouse T cell antigen receptor have been isolated on a single cosmid clone. There are two constant genes, C beta 1 and C beta 2, each associated with a cluster of J beta gene segments. The nucleotide sequences of the C beta 2 gene and of the J beta 2 cluster gene segments have been determined. The coding sequence of the C beta 2 gene is very similar to the sequence of a cDNA clone encoded by the C beta 1 gene. The C beta 2 gene has four exons; exon-intron structure does not obviously correspond to the functional domains of the protein. The J beta 2 gene segment cluster contains six functional J gene segments. We have isolated specific probes for the C beta 1, C beta 2, J beta 1, and J beta 2 regions to examine DNA rearrangements in T lymphocytes. DNA rearrangements can occur in both J beta gene segment clusters, and both C beta genes appear functional.

Animals↗
PubMed1984

Enhancement of macrophage survival and complement production by factors from cloned T cells.

The addition of supernatants of some cloned mouse T cell lines to guinea pig peritoneal cells in tissue culture increased the production of the second (C2) and fourth (C4) components of complement as well as the enzyme beta-glucuronidase. Enumeration of cell populations demonstrated a simultaneous increase in cell survival. Supernatants that augmented functions of the cultured cells were obtained after alloantigen stimulation of a T cell line of C57BL/6 origin termed L2, but supernatants from a variant cell line derived from L2 and termed L2V had no effect. A delay of as little as 24 h in the addition of L2 T cell factors at the start of the cultures markedly diminished the effects on the cultured cells that were ordinarily observed 1-2 weeks later. These experiments suggest that, in this xenogenic system, complement-enhancing activity is part of a general stimulation of macrophages by cloned T cell factors.

Animals↗
PubMed1984

Comparison of allogeneic and self-restricted stimulation of lymphokine production by dual-reactive cloned T cells.

Murine T cell clones were derived that proliferated in response to stimulation by alloantigen or by ovalbumin (OVA) in the presence of irradiated syngeneic spleen cells. Two cloned cell lines of strain B10.BR (H-2k) proliferated in response to alloantigen encoded by I-Ab, whereas the response to OVA was restricted by an element encoded by I-Ak. A cloned cell line of strain B10.A (H-2a) proliferated in response to alloantigen encoded by I-As, whereas the response to OVA was restricted by an element encoded by I-Ak. Cloned cells were stimulated by alloantigen or by OVA to produce lymphokines and to incorporate thymidine. Culture supernatants were collected 24 hr later and were assayed for interleukin 2, colony stimulating factor, interferon, Ia-inducing activity, and interleukin 3; thymidine incorporation was measured 72 hr after stimulation. For each clone tested, stimulation by alloantigen or by OVA led to the production of an identical array of lymphokines. Likewise, the strength of stimulation by alloantigen was approximately equal in magnitude to the strength of stimulation by a particular concentration of OVA. Lymphokine production and thymidine incorporation were co-variant measures of the intensity of stimulation. These data, in combination with data linking OVA reactivity and alloreactivity to identical regions of the major histocompatibility complex, suggest that dual reactivity represents a cross-reaction between alloantigen and self determinants associated with nominal antigen.

Animals↗
PubMed1984

Antigen-reactive cloned helper T cells. II. Exposure of murine cloned helper T cells to IL 2-containing supernatant induces unresponsiveness to antigenic restimulation and inhibits lymphokine production after antigenic stimulation.

Cloned murine helper T lymphocytes (HTL) reactive to alloantigen or to ovalbumin (OVA) become unresponsive to antigenic restimulation after exposure to antigen or to culture supernatant fluids (SF) containing multiple lymphokine activities. Unresponsiveness is manifest by a failure of antigen-stimulated cells to incorporate thymidine or to produce lymphokines after antigenic challenge. Antigen-unresponsive HTL, however, will incorporate thymidine when exposed to an exogenous source of interleukin 2 (IL 2). The duration of unresponsiveness to antigen is correlated with the concentration of IL 2 in SF to which the cloned HTL had been exposed. Chromatographic fractionation of IL 2-containing supernatant from EL-4 thymoma cells (EL-4 SF) yielded a pool of SF that was enriched for IL 2 activity. Exposure of HTL to lymphokines contained in this pool induced unresponsiveness to antigen that was comparable to that observed when HTL were exposed to unfractionated EL-4 SF. Unresponsiveness to antigen also developed after cloned HTL were stimulated with concanavalin A (Con A) or with OVA and syngeneic splenic filler cells. We have used monoclonal antibody (mAb) GK1.5 (anti-L3T4) to investigate the role of lymphokine production in the induction of unresponsiveness. This antibody did not inhibit IL 2-induced thymidine incorporation by cloned HTL, and did not inhibit the induction of unresponsiveness after exposure of cloned HTL to EL-4 SF. In the presence of mAb GK1.5, however, HTL that were stimulated with Con A or OVA did not become unresponsive to antigenic restimulation, an effect that was overcome by the addition of EL-4 SF. These results suggest that HTL become unresponsive to antigen after exposure to IL 2-containing SF, and that stimulation by antigen or Con A can induce the unresponsive state by virtue of stimulating lymphokine production.

Animals↗
PubMed1984

Effects of monoclonal antibodies directed against murine T lymphocyte cell surface antigens on lymphokine production by cloned T lymphocytes reactive with class I MHC or Mls alloantigens.

Monoclonal antibodies recognizing murine T lymphocyte cell surface structures implicated in T lymphocyte-mediated cytolysis, including Lyt-2, L3T4, LFA-1, and a cytolytic T lymphocyte (CTL) clonotypic determinant, were used as probes to investigate the role of these structures in lymphokine production by T cell clones induced by antigen or lectin. The clone-specific antibody 384.5 bound to and inhibited antigen-induced lymphokine production by the L3 CTL clone, but did not affect lymphokine production by other T cell clones. Antibodies against the T cell surface structures Lyt-2 or L3T4, which are expressed by mutually exclusive T cell subsets, inhibited antigen-induced lymphokine production by class I major histocompatibility complex (MHC) antigen-reactive CTL clones or an M1s-reactive helper T lymphocyte (HTL) clone, respectively. Antibody against the broadly distributed LFA-1 molecule inhibited antigen-induced lymphokine production by all of the clones tested. Lectin-induced lymphokine production by cloned T cells was not inhibited by the clonotypic antibody, anti-Lyt-2, or anti-LFA-1; slight inhibition of the HTL clone was observed with the anti-L3T4 antibody. None of these structures appear to be uniquely involved with a particular functional response. Our results suggest that each of these structures is involved with the interactions between the effector cell and the stimulating cell leading to lymphokine production.

Animals↗
PubMed1984

TRF requirements for in vitro PFC responses to SRBC and R36a. I. TRF is distinct from IL 2 but indistinguishable from polyclonal BCSF.

In vitro PFC responses to the thymus-independent (TI) antigen Streptococcus pneumoniae R36a require T cell replacing factor(s) (TRF). This requirement for TRF is as significant as for the thymus-dependent (TD) antigen SRBC. TRF is shown to be distinct from IL 2 by the following observations: 1) culture supernatants from the cloned T cell line L2, collected over an 8-day period after allogeneic stimulation, transiently contain IL 2 activity but maintain high levels of TRF activity throughout 192 hr; 2) L2V, a variant subclone of L2, produces much higher levels of TRF activity than the parental line but no detectable IL 2 activity; 3) the addition of IL2+, TRF- supernatants from the T cell hybridoma FS6-14.13 does not affect the L2V SF-driven PFC responses to R36a or SRBC; and 4) the addition of contaminating T cells to cultures containing T cell-depleted spleen cells, L2V SF, and antigen does not affect the PFC response. TRF does appear to be indistinguishable from polyclonal B cell stimulating factor (BCSF), which stimulates polyclonal PFC responses in the absence of antigen, mitogen, or anti-Ig. The TRF and BCSF activities of L2V SF could not be separated by ion-exchange, hydrophobic-interaction, and gel-filtration chromatography. TRF and BCSF have an apparent m.w. of approximately 40,000.

Animals↗
PubMed1984

Multiple hemopoietic lineages are found after stimulation of mouse bone marrow precursor cells with interleukin 3.

When the murine T-lymphocyte clone L2 is stimulated with concanavalin A, it secretes at least two distinct factors that affect hemopoietic precursor cells, interleukin 3 (IL3) and granulocyte/macrophage colony-stimulating factor (GM-CSF). IL3 accounts for approximately 10% of the colony-stimulating activity in L2-cell-conditioned medium. The IL3 secreted by L2 cells is similar antigenically to the IL3 secreted by WEHI-3 cells. Like the IL3 from WEHI-3 cells, IL3 secreted by L2 cells does not bind to DEAE Sephacel and can be separated from the L2-cell GM-CSF, which does bind to DEAE. By assessment of the functional, morphologic, surface phenotypic, and cytochemical characteristics of bone marrow cells 6 days after stimulation with IL3 in liquid culture, four hemopoietic lineages were found, including macrophage, neutrophilic granulocyte, megakaryocyte, and basophil/mast cell. In addition, when bone marrow cells were stimulated with IL3 in semisolid medium, several types of colonies were found, including mixed colonies containing macrophage, megakaryocyte, and granulocyte lineages.

Animals↗
PubMed1984

A microassay for colony-stimulating factor based on thymidine incorporation.

A variety of growth factors and lectins were tested; only colony-stimulating factors CSF-1, Interleukin 3, and a T-lymphocyte GM CSF induced colony formation in semisolid medium and stimulated thymidine incorporation in liquid culture. All other growth factors and lectins were inactive in both assays. Factor-stimulated thymidine incorporation was detectable 24 hours after stimulation and reached maximal levels 4-6 days after stimulation. A convenient microassay for measuring CSF activity has been developed, enabling a large number of samples to be screened qualitatively in 2 days and permitting CSF activity to be measured quantitatively in 4-5 days. This microassay can supplement the clonal-cell assay method and be especially useful as an initial screening assay for CSF activity.

Animals↗
PubMed1983

Biochemical enrichment of lymphokines secreted by a cloned helper T lymphocyte.

The Mls-reactive murine helper T cell clone L2 produces at least 10 lymphokine activities affecting at least five distinct target cells. Culture conditions can be optimized to enable production of high levels of colony-stimulating factors (CSFs) by lectin stimulation of L2 cells under serum-free conditions. Selective enrichment of three lymphokine activities--interleukin 2, CSF, and interferon--can be achieved by using a combination of phenyl-Sepharose and hydroxyapatite chromatography. At least two types of CSF can be separated by concanavalin A-Sepharose chromatography. The CSF that does not bind to concanavalin A-Sepharose can be enriched to a specific activity of at least 5 X 10(8) U/mg of protein by using ion exchange high-pressure liquid chromatography.

Animals↗