Combination Of Phytohemagglutinin Research Articles

Phytohemagglutinin fromPhaseolusvulgarisenhancesthelungcancercell chemotherapy sensitivitybychangingcellmembrane permeability.

Chemotherapy is still a prevalent strategy for clinical lung cancer treatment. However, the inevitable emerged drug resistance has become a great hurdle to therapeutic effect. Studies have demonstrated that the primary cause of drug resistance is a decrease in the chemotherapeutic medicine concentration. Several lectins have been confirmed to be effective as chemotherapy adjuvants, enhancing the anti-tumor effects of chemotherapy drugs. Here, we combined phytohemagglutinin (PHA), which has been reported possess anti-tumor effects, with chemotherapy drugs Cisplatin (DDP) and Adriamycin (ADM) on lung cancer cells to detect the sensitivities of PHA as a chemotherapy adjuvant. Our results demonstrated that the PHA significantly enhanced the sensitivity of lung cancer cells to DDP and ADM, and Western blot showed that PHA combined with DDP or ADM enhance cytotoxic effects by inhibiting autophagy and promoting apoptosis. More importantly, we found PHA enhanced the chemotherapeutic drugs cytotoxicity by changing the cell membrane to increase the intracellular chemotherapeutic drugs concentration. Besides, the combination of PHA and ADM increased the ADM concentration in the multidrug-resistant strain A549-R cells and achieved the drug sensitization effect. Our results suggest that PHA combined with chemotherapy can be applied in the treatment of lung cancer cells and lung cancer multidrug-resistant strains, and provide a novel strategy for clinical tumor chemotherapy and a new idea to solve the problem of drug resistance in clinical lung cancer.

P1-280 - Phytohemagglutinin chemosensitizes lung cancer cells to Liposomal Cisplatin by cell cycle arrest

Phytohemagglutinin (PHA) has mitogenic and potent cell agglutinating activities. It binds to T-cell membranes and stimulates cell division and metabolic activity. PHA has the ability to stimulate close contacts between cell membranes. Lipoplatin (Liposomal cisplatin) is a nanoparticle of 110 nm average diameter composed of lipids and cisplatin. This new drug has successfully finished Phase I, Phase II and Phase III human clinical trials. It has shown superiority to cisplatin in combination with paclitaxel as a chemotherapy regimen in non-small cell lung cancer (NSCLC) adenocarcinomas. The aim of this study was to investigate whether PHA would be able to enhance the antitumor effects of Lipoplatin in MCF-7 and MDA-MB-231 cells. PHA potentiated the cytotoxic effects of Lipoplatin in human lung cancer cells. This finding was related to the ability of PHA to sensitize MCF-7 cells to Lipoplatin-induced apoptosis. The sensitization by PHA involved the enhancement of p53 levels, the decrease of procaspase 8 and the activation of caspases 7 and 9. Another proposed mechanism for the chemosensitization effect of MCF-7 cells to Lipoplatin by PHA was the cell cycle arrest in the S phase. The treatment with PHA or Lipoplatin increased the levels of p-Chk2. The increase became pronounced in the combined treatments of the compounds. The expression of cyclin A was decreased by treatment with PHA and by the combination of PHA with Lipoplatin. While the levels of cyclin dependent kinase 2 (CDK2) remained unchanged by treatments, its active form (Thr(160) -phosphorylated CDK2) was decreased by treatment with PHA and by the combination of PHA with Lipoplatin. The activity of CDK7, kinase that phosphorylates CDK2 at Thr(160), was inhibited by PHA and by the combination of PHA with Lipoplatin. These results indicate that PHA could be used as an adjuvant agent during lung cancer therapy with Lipoplatin.

Release kinetics of tumor necrosis factor-α and interleukin-1 receptor antagonist in the equine whole blood.

BackgroundHorses are much predisposed and susceptible to excessive and acute inflammatory responses that cause the recruitment and stimulation of polymorphnuclear granulocytes (PMN) together with peripheral blood mononuclear cells (PBMC) and the release of cytokines. The aim of the study is to develop easy, quick, cheap and reproducible methods for measuring tumor necrosis factor alpha (TNF-α) and interleukin-1 receptor antagonist (IL-1Ra) in the equine whole blood cultures ex-vivo time- and concentration-dependently.ResultsHorse whole blood diluted to 10, 20 and 50 % was stimulated with lipopolysaccharide (LPS), PCPwL (a combination of phytohemagglutinin E, concanavalin A and pokeweed mitogen) or equine recombinant TNF-α (erTNF-α). TNF-α and IL-1Ra were analyzed in culture supernatants, which were collected at different time points using specific enzyme-linked immunosorbent assays (ELISA). Both cytokines could be detected optimal in stimulated 20 % whole blood cultures. TNF-α and IL-1Ra releases were time-dependent but the kinetic was different between them. PCPwL-induced TNF-α and IL-1Ra release was enhanced continuously over 24–48 h, respectively. Similarly, LPS-stimulated TNF-α was at maximum at time points between 8–12 h and started to decrease thereafter, whereas IL-1Ra peaked later between 12–24 h and rather continued to accumulate over 48 h. The equine recombinant TNF-α could induce also the IL-1Ra release.ConclusionsOur results demonstrate that similar to PCPwL, LPS stimulated TNF-α and IL-1Ra production time-dependently in whole blood cultures, suggesting the suitability of whole blood cultures to assess the release of a variety of cytokines in health and diseases of horse.

Psychological Stress and Cytokine Production in Multiple Sclerosis

Psychological variables such as perceived stress appear to play a role in symptom onset or disease exacerbation in multiple sclerosis (MS). The authors sought to determine if perceived stress is indeed associated with the expression of pro-inflammatory cytokines and disease symptoms in individuals with MS. To do so, the authors examined the relationships among disease symptomatology, perceived stress, and cytokine production from peripheral blood mononuclear cells in 42 outpatients with MS and 36 normative controls. The authors drew peripheral blood from all subjects prior to the completion of a series of psychological instruments. The authors measured stress using the Perceived Stress scale and negative mood with the Profile of Mood States. Disease symptoms were measured using the Multiple Sclerosis Symptom Checklist. Cytokine production was induced separately by lipopolysaccharide and a combination of phytohemagglutinin and phorbol-12-myristate-13-acetate. In MS subjects, the induced production of interleukin (IL)-6 and IL-10 positively correlated with psychological stress, mood disturbance, and disease symptomatology. In contrast, psychological stress in control subjects significantly correlated with level of tumor necrosis factor-alpha (TNF-α), and mood disturbance correlated with levels of TNF-α and interferon-gamma. As well, compared to controls, MS subjects exhibited a significant fourfold increase in the production of IL-12. There is, in those with MS, a pattern of IL-6 and IL-10 production that correlates significantly with perceived stress and disease symptomatology.

Limited efficiency of endogenous interleukin-7 levels in T cell reconstitution during HIV-1 infection: will exogenous interleukin-7 therapy work?

Limited efficiency of endogenous interleukin-7 levels in T cell reconstitution during HIV-1 infection: will exogenous interleukin-7 therapy work?

The synergistic effect of phytohemagglutinin and interferon-γ on the expression of tumor necrosis factor-α from RAW 264.7 cells

Tumor necrosis factor-α (TNF-α) is a major cytokine of host immune reaction by foreign agents. Phytohemagglutinin (PHA) is a dynamic contributor to mitogenic stimulation and augmentation of host immune defense. Interferon-γ (IFN-γ) induces induction of cytokines in macrophages and lymphocytes. The aim of this study was to examine the synergistic effects of PHA plus low dose IFN-γ on TNF-α mRNA production, cytosolic levels, and secretion in RAW 264.7 cells. The cells were stimulated with PHA or IFN-γ using various concentrations for various times. The effects of PHA on TNF-α expression appeared in dose- and time-dependent manners. The maximum doses of PHA and IFN-γ to produce them were 300 μg/ml PHA and 10 ng/ml IFN-γ. The optimum time of PHA for the TNF-α mRNA production and release were 6 and 7 h after stimulation, respectively, whereas the time of IFN-γ on them was achieved at 3 and 8 h. Although the TNF-α mRNA production, cytosolic levels, and secretion from the cells were slightly detected under 10 μg/ml PHA and 1 ng/ml IFN-γ, the combination of PHA (10 μg/ml) and IFN-γ (1 ng/ml) greatly increased them, indicating the synergistic effect of PHA plus low dose IFN-γ on TNF-α expression.

Significance of phosphotyrosine proteins, Bcl-2 and p53 for apoptosis in resting B-chronic lymphocytic leukemia (CLL) cells.

Signal transduction and apoptosis in B-cell chronic lymphocytic leukemia (CLL) cells with a post-germinal center (GC) phenotype were studied. Specific activation of the cells was induced by a combination of soluble anti-CD40 monoclonal antibody and interleukin-4 (CD40/IL-4) and nonspecific activation with a combination of phytohemagglutinin, phorbol-12-myristate-13-acetate and ionomycin (chemical mixture). Less than 5% of these leukemia cells entered the cell cycle after activation, as indicated by the number of cells in G0/G1 phase. The protein tyrosine phosphorylation pattern and expression of the Bcl-2 protein were specific in ex vivo CLL cells of each individual patient. Expression of the p53 protein was not detectable in these leukemia cells. Cross-linking of the CD40/IL-4 receptors on CLL cells significantly upregulated phosphotyrosine proteins and the p53 protein. In the presence of chemical mixture, downregulated phosphotyrosine proteins were detected. Alterations in Bcl-2 expression were independent of cross-linking with CD40/IL-4 or chemical mixture. A high frequency of apoptotic cells was detected in cells that had downregulated phosphotyrosine proteins and Bcl-2 protein. There was no correlation between induction of apoptosis and expression of p53 protein. Our results suggest that apoptosis in resting leukemia cells could occur prior to the cell cycle progression. Alterations in phosphotyrosine proteins and Bcl-2 but not p53 might play an important role in the regulation of apoptosis in resting G0/G1 memory post-GC B-CLL cells.

Effects of a Combination of Traditional Chinese Botanicals (Immune+) on the Secretion of Interleukin-1beta and Interferon-gamma by Peripheral Blood Mononuclear Cells.

The use of herbal and other botanical products, including those used extensively in traditional Chinese medicine, has increased dramatically in the last decade. Yet, little scientific research exists concerning their efficacy and safety. We examined the effects of Immune+, a combination of five botanicals frequently used in traditional Chinese medicine, on the production of two cytokines. For this purpose, unstimulated or phytohemagglutinin (PHA)-stimulated peripheral blood mononuclear cells from healthy volunteers were incubated with different concentrations of Immune+. The secretion of interleukin-1beta (IL-1beta) and interferon-gamma (IFN-gamma) was measured after 72 hours of incubation. At the highest concentration tested (100 micro g/ml), Immune+ significantly increased the secretion of IL-1beta. Importantly, PHA alone had no effect on IL-1beta production, and the combination of PHA with Immune+ resulted in the same increase in IL-1beta production as seen with the botanical extract alone. Immune+ did not have any detectable effect on either unstimulated or PHA-stimulated IFN-gamma synthesis. These in vitro data support the concept that Immune+ may enhance human immune responses.

Measurement of cytokine secretion, intracellular protein expression, and mRNA in resting and stimulated peripheral blood mononuclear cells.

Quantitation of cytokine production is a valuable adjunct to standard immunologic assays in defining several pathologic processes. Nevertheless, there is little agreement about which tissues should be assayed, which type of assay should be performed, and which stimulation protocol should be used. As these types of assays enter the clinical arena, there is need for standardization. There is also a need to maximize the amount of information which may be derived from a single sample. We compared secreted interleukin 4 (IL-4), IL-2, IL-6, tumor necrosis factor alpha (TNF-alpha), and gamma interferon proteins as measured by enzyme-linked immunosorbent assay with intracellular cytokine production (IL-2 and gamma interferon) as detected by flow cytometry and quantitative competitive PCR for IL-2, IL-4, TNF-alpha, and gamma interferon mRNA and cDNA. Results from unstimulated cells and cells stimulated with phorbol myristate acetate, phytohemagglutinin, and phorbol myristate acetate plus phytohemagglutin were compared. All three methodologies detected significant stimulation of cytokine production. The combination of phytohemagglutinin and phorbol myristate acetate was overall the most-potent stimulus.

High Serum Levels of Soluble IL-2 Receptor, Cytokines, and C Reactive Protein Correlate with Impairment of T Cell Response in Patients with Advanced Epithelial Ovarian Cancer

The serum levels of interleukin-(IL-)1α, IL-1β, IL-2, IL-6, TNFα, and sIL-2R and the proliferative response of peripheral blood mononuclear cells (PBMC) to phytohemagglutinin (PHA), anti-CD3 monoclonal antibody (mAb), recombinant IL-2 (rIL-2), and the combination of PHA or anti-CD3 mAb with rIL-2 were studied and correlated with serum levels of C-reactive protein (CRP) in women with advanced epithelial ovarian cancer. The expression of CD25 and CD122 subunities of membrane-bound IL-2R on PHA- or anti-CD3 mAb-stimulated PBMC was also studied. In comparisons with the controls, PBMC response to PHA, anti-CD3 mAb, and rIL-2 was significantly lower in the cancer patients. The addition of exogenous rIL-2 to the PBMC cultures increased response in both controls and patients but did not modify the significance of the differences. After stimulation with PHA or anti-CD3 mAb, the percentage of PBMC CD25+or CD122+was significantly lower in patients. The serum levels of IL-1α, IL-1β, IL-6, TNFα, sIL-2R, and CRP were significantly increased in patients compared to the controls. Instead, no differences were observed for serum levels of IL-2. A strong association was found between high serum levels of the above-mentioned cytokines, sIL-2R, and CRP. The results of our study on advanced stage (IIIb–IV) ovarian cancer patients are consistent with the previously reported hypothesis that high IL-6 and/or CRP serum levels may represent an important and independent prognostic factor of the likely outcome in cancer patients.

In vitro interleukin-1 and 2 production and interleukin 2 receptor expression in the rhesus monkey

Anti-human monoclonal antibodies were used to detect and quantify interleukins-1 and 2 and interleukin-2 receptor expression in peripheral blood mononuclear cells from a rhesus monkey. Interleukin-1 production could be induced by phorbol esters (PMA) and was potentiated by phytohemagglutinin (PHA). Interleukin-2 secretion could also be induced by the combination of PHA and PMA, but only weakly with PHA alone. Interleukin-2 receptor expression was present in a subpopulation of unstimulated lymphocytes and could be enhanced by PHA or PMA. These data show once again that the rhesus monkey immune system is cross-reactive with the human one and that rhesus macaque could be a good model to study interleukin therapy.

Effect of corticosteroids, cyclosporin A, and methotrexate on cytokine release from monocytes and T-cell subsets

Corticosteroids are the most effective drugs in the management of asthma. However, because of their known side effects and the existence of corticosteroid-resistant patients, there is a need for substitute medications in asthma therapy. Using cell lines, in the present study, the two corticosteroids dexamethasone (Dex), and beclomethasone (Bec), as well as the immunosuppressant cyclosporin A (CsA), and the antimetabolic drug methotrexate (Mtx) were examined in their effect on release of immunoreactive IL-1β, IL-2, IL-4, IL-5, and IL-8. THP-1 cells served as a test model for monocytes secreting IL-1β and IL-8 upon stimulation by lipopolysaccharide. Jurkat cells were used as a test model for TH 1-type T-cells and were stimulated for IL-2 release with a combination of phytohemagglutinin and phorbol myristate acetate. Representing TH2-type T-cells, D10.G4.1 cells challenged by anti-CD3-mAb produced IL-4, and IL-5. Considerable qualitative and quantitative differences in the relative efficacy of the test compounds were found. Following IC50 values (nmol/1) of the test compounds were estimated (IL-1β/IL-8/IL-2/IL-4/IL-5): Dex (10.8/35.7/>10,000.0/5.1/4.1), Bec (30.9/102.2/8591.4/0.6/0.4), CsA (318.7/6211.2/2.3/68.2/237.9). Mtx in concentrations up to 10,000.0 nmol/1 was completely inactive. It can be concluded that corticosteroids show another inhibition pattern than CsA: corticosteroids affect mainly Th2-type T-cells, while CsA primarily inhibits the Th1-type T-cell response.)

Thrombin and thrombin receptor agonist peptide induce early events of T cell activation and synergize with TCR cross-linking for CD69 expression and interleukin 2 production.

Thrombin stimulation of the T leukemic cell line Jurkat induced a transient increase in [Ca2+]i. Proteolytic activity of the enzyme was required for this effect since diisopropyl fluorophosphate-thrombin failed to increase [Ca2+]i. Furthermore, hirudin and anti-thrombin III inhibited the thrombin-induced [Ca2+]i rise in Jurkat T cells. A synthetic thrombin receptor agonist peptide (TRP) of 7 residues (SFLLRNP) was found to be as effective as thrombin for [Ca2+]i mobilization, and both agonists induced Ca2+ release exclusively from internal stores. Thrombin stimulated tyrosine phosphorylation of several proteins of molecular mass 40, 42, 70, 120, and 130 kDa. There was a good correlation between thrombin-induced tyrosine phosphorylation of the latter three proteins and Ca2+ mobilization. Thrombin and TRP also caused translocation of protein kinase C from the cytosol to the plasma membrane. As a likely consequence of these events, thrombin activated the nuclear factor NF-kB. Several cell lines of hematopoietic origin including the leukemic T cell line HPB.ALL and the erythroleukemic cell line K562 were responsive to thrombin, whereas others such as THP1, a myelomonocytic cell line, and BL2, a Burkitt lymphoma were refractory to thrombin or TRP stimulation. The magnitude of the thrombin response in the different cell types paralleled the expression of the thrombin receptor mRNA. We found that activation of Jurkat T cells by a combination of phytohemagglutinin and phorbol 12-myristate 13-acetate led to a dramatic inhibition of thrombin receptor mRNA expression and to a concomitant loss of the thrombin response. Finally, we demonstrate that thrombin and TRP enhanced CD69 expression and interleukin 2 production induced by T cell receptor cross-linking in both Jurkat T cells and peripheral blood lymphocytes. These findings highlight the role of thrombin as a potential regulator of T lymphocyte activation.

Microtubules Are Not an Essential Component of Phytohemagglutinin-Dependent Signal Transduction in Jurkat T Lymphocytes

We have used two disruptors of the cytoskeleton microtubular network (colchicine and vinblastine) to investigate the role of microtubules in Phaseolus vulgaris phytohemagglutinin (PHA) signal transduction in Jurkat T cells. Both drugs decreased but did not abolish the PHA-dependent Ca 2+ response of Jurkat cells. Neither colchicine nor vinblastine had any major effects on the PHA-dependent turnover of the mono-, di-, tri-, and tetra-substituted phosphorylated derivatives of D- myo-inositol or the cellular distribution of protein kinase C (PKC) activity. However, both microtubule disruptors increased interleukin-2 (IL-2) production. Whereas vinblastine enhanced IL-2 production approximately twofold at all the concentrations tested (0.1, 1.0, and 10 μ M), colchicine did so only at a 10 μ M concentration. When a combination of PHA and 12- O-tetradecanoyl-13- O-acetyl phorbol (TPA) was used, a small increase in IL-2 production was observed only in the presence of vinblastine (10 μ M). In contrast to recent reports that microfilaments may be involved in the regulation of signal transduction, our data suggest that this is not the case for microtubules in PHA-dependent signal transduction in Jurkat T cells.

T lymphocytes and their CD4 subset are direct targets for the inhibitory effect of calcitriol

We studied the direct effects of the hormone calcitriol on the activation and proliferation of pure T lymphocytes and their subsets. Calcitriol inhibited the proliferation of T lymphocytes stimulated in the absence of monocytes with phytohemagglutinin (PHA) and either a monocytic culture supernatant or a combination of monocyte-derived interleukin 1 and interleukin 6. This inhibition was not influenced by the concentration of the stimulating agents. The minimal effective concentration of calcitriol was 10 −10 M. In contrast, the interleukin 2 (10 U/ml)-driven growth of PHA-stimulated T lymphocytes was not significantly altered by calcitriol at 10 /t-8 M. The hormone had also no influence on the T lymphocyte proliferation induced by a combination of PHA and the anti-CD28 monoclonal antibody 9.3. Pure T lymphocytes, after incubation for 5 days with PHA and monocytic factors, expressed a high level of transferrin receptors. This phenomenon was strongly suppressed on both CD4 and CD8 subsets when 10 −8 M calcitriol had been present during the culture. Moreover, the proliferation of pure CD4 cells was directly inhibited by calcitriol in similar conditions as for unseparated T lymphocytes. We conclude that T lymphocytes and their CD4 subset are direct targets for the inhibitory effect of calcitriol.

Oxalyl thiolester concentrations decreased in lectin and phorbol ester-stimulated lymphocytes.

Oxalyl thiolesters (OTEs) are a newly discovered class of mammalian metabolites that are believed to function in controlling animal metabolism and possibly serve as intracellular mediators for some hormones. Previous correlations had suggested that the concentrations of OTEs might be decreased when cells are stimulated to proliferate, and in our research that was found to be the case. Thus, when bovine lymph node lymphocytes are stimulated either with concanavalin A (Con A) or with a combination of phytohemagglutinin (PHA) and the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA), the concentration of OTEs in the lymphocytes decreases within 3 h by a factor of approximately two. With either PHA or TPA alone, the decrease in OTE concentration is considerably smaller. With Con A as stimulant, the OTE levels decrease within 1 h and remain low for at least 24 h. It was also noted that the concentration of OTEs in unstimulated isolated lymphocytes is significantly lower in lymphocytes obtained from 2-year-old animals than in lymphocytes obtained from older animals. The results of the current investigation, when considered in conjunction with other recent results, suggest that OTEs may be natural cell proliferation inhibitors.

Two mechanisms of spermidine/spermine N1-acetyltransferase induction

The changes in activity of spermidine/spermine N 1-acetyltransferase (SAT), a rate-limiting enzyme in polyamine degradation, were investigated to understand the mechanism of the induction of this enzyme in bovine lymphocytes. The activity of SAT was induced by stimulation with phytohemagglutinin (PHA), calcium ionophore A23187, sodium n-butyrate, or methylglyoxal bis(guanylhydrazone) (MGBG). When the cells were treated with a combination of PHA with either MGBG or butyrate, the increase in SAT was synergistic. However, the treatment of cells with both PHA and A23187 did not cause more induction of the enzyme activity than the stimulatory effects of each agent alone. The elevation in SAT caused by PHA or A23187 was inhibited by the simultaneous addition of 25 μ m H-7, a protein kinase C inhibitor; the induction of the enzyme activity by MGBG or butyrate was slightly enhanced in the presence of H-7. In cells treated with a high concentration of O-tetradecanoylphorbol 13-acetate, which results in the breakdown of protein kinase C, PHA and A23187 did not give the maximum response, and MGBG slightly enhanced the enzyme activity. Dibutyryl cyclic AMP inhibited PHA-induced enzyme activity, but it stimulated MGBG- or butyrate-induced activity. Exposure to PHA or A23187 but not to MGBG or butyrate significantly increased the ornithine decarboxylase activity and DNA synthesis. These results showed that there were two different mechanisms of SAT induction. One is dependent on protein kinase C. The other one is independent of protein kinase C and is enhanced by cyclic AMP.

Signals involved in T cell activation. II. Distinct roles of intact accessory cells, phorbol esters, and interleukin 1 in activation and cell cycle progression of resting T lymphocytes.

The signals involved in the initiation of mitogen-induced activation of resting guinea pig T cells were examined. The combination of phytohemagglutinin (PHA) and 4 beta-phorbol 12-myristate 13-acetate (PMA) stimulated DNA synthesis by accessory cell (AC)-depleted T cells cultured at high density, but the use of low density cultures indicated that intact AC were absolutely necessary for PHA-stimulated T cell DNA synthesis even in the presence of PMA, interleukin 1 (IL 1), or interleukin 2 (IL 2). In contrast, AC-depleted T cells were able to respond to the combination of the calcium ionophore, ionomycin, and PMA regardless of the cell density at which they were cultured. Cell cycle analysis by acridine orange staining indicated that neither PHA nor ionomycin, in the absence of AC, activated resting T cells. PMA in the absence of all AC, supported cell cycle entry and progression to the DNA synthetic phase of the majority of ionomycin-stimulated T cells, but permitted only a small number of PHA-triggered T cells to enter the initial stage of the cell cycle (G1a) characterized by a modest increase in cellular RNA content. Although PMA permitted some PHA-stimulated T cells to enter the cell cycle, most required intact AC to enter G1, and all required intact AC to progress through G1 and synthesize maximal amounts of RNA. No PHA-stimulated cells reached the S phase without intact AC. In PHA-stimulated cultures containing intact AC, PMA increased the number of cells entering the cell cycle and increased the rate of their progress to the DNA synthetic phase. IL 1 also augmented PHA-stimulated AC-dependent T cell DNA synthesis in the presence or absence of PMA, but appeared to be most active during the later stage of the first cell cycle, augmenting the number of activated cells that entered the S phase of the cell cycle. These results support the conclusion that intact AC, IL 1, and a PMA-like signal play distinct roles in the progression of mitogen-stimulated T cells through the first round of the cell cycle.

Growth, Interleukin-2 Production, and Responsiveness to IL-2 in T4-Positive T Lymphocyte Populations From Malignant Cutaneous T Cell Lymphoma (Sézary’s Syndrome): The Effect of Cyclosporine A

Abstract Functional analysis and surface phenotyping using monoclonal antibodies have revealed that malignant T lymphocyte populations in the peripheral blood of patients with Sezary's syndrome resemble the T helper cell populations from normal individuals. In this article we have studied the effects of the immunosuppressive drug cyclosporine A (CsA) on growth, interleukin-2 (IL-2) production, and the induction of IL-2 responsiveness of peripheral blood monocytes (PBMs) from five patients with Sezary's syndrome in vitro, using the lectin phytohemagglutinin (PHA) and the phorbol ester phorbol myristate acetate (PMA) as stimuli. The following results were obtained: PHA-induced cell proliferation was significantly more sensitive to inhibition by CsA than that induced by PMA or a combination of PMA and PHA (P less than .005). Sezary PBMs produced only small amounts of IL-2 in response to PHA. Stimulation with PMA, however, resulted in significant IL-2 production. PMA and PHA, when given in combination, acted synergistically. The low levels of IL-2 production induced by PHA or PMA were more sensitive to CsA- mediated suppression than those induced by a combination of PHA and PMA (75% and 55% suppression, respectively). CsA-mediated growth suppression could be overcome if the cultures were supplemented with appropriate amounts of exogenous IL-2. We conclude from our data, that CsA in Sezary PBMs inhibits T cell growth indirectly as a consequence of suppression of IL-2 growth indirectly as a consequence of suppression of IL-2 production. Moreover, like normal T lymphocytes, Sezary PBMs do not express the IL-2 receptor spontaneously, but can be induced to do so. CsA does not interfere with intracellular events leading to the expression and the biologic function of the IL-2 receptor.

Growth, interleukin-2 production, and responsiveness to IL-2 in T4- positive T Lymphocyte populations from malignant cutaneous T cell lymphoma (Sezary's syndrome): the effect of cyclosporin A

Functional analysis and surface phenotyping using monoclonal antibodies have revealed that malignant T lymphocyte populations in the peripheral blood of patients with Sézary's syndrome resemble the T helper cell populations from normal individuals. In this article we have studied the effects of the immunosuppressive drug cyclosporine A (CsA) on growth, interleukin-2 (IL-2) production, and the induction of IL-2 responsiveness of peripheral blood monocytes (PBMs) from five patients with Sézary's syndrome in vitro, using the lectin phytohemagglutinin (PHA) and the phorbol ester phorbol myristate acetate (PMA) as stimuli. The following results were obtained: PHA-induced cell proliferation was significantly more sensitive to inhibition by CsA than that induced by PMA or a combination of PMA and PHA (P less than .005). Sézary PBMs produced only small amounts of IL-2 in response to PHA. Stimulation with PMA, however, resulted in significant IL-2 production. PMA and PHA, when given in combination, acted synergistically. The low levels of IL-2 production induced by PHA or PMA were more sensitive to CsA-mediated suppression than those induced by a combination of PHA and PMA (75% and 55% suppression, respectively). CsA-mediated growth suppression could be overcome if the cultures were supplemented with appropriate amounts of exogenous IL-2. We conclude from our data, that CsA in Sézary PBMs inhibits T cell growth indirectly as a consequence of suppression of IL-2 growth indirectly as a consequence of suppression of IL-2 production. Moreover, like normal T lymphocytes, Sézary PBMs do not express the IL-2 receptor spontaneously, but can be induced to do so. CsA does not interfere with intracellular events leading to the expression and the biologic function of the IL-2 receptor.