IL-2-PE40对免疫活性T细胞的影响

目的研究ＩＬ－２－ＰＥ４０对免疫活性Ｔ细胞的影响。方法采用ＣｏｎＡ刺激的淋巴细胞增殖试验、混合淋巴细胞培养（ＭＬＣ）及细胞毒试验。结果ＩＬ－２－ＰＥ４０对ＣｏｎＡ诱导的小鼠脾细胞有十分强的细胞毒性，能选择性地抑制ＭＬＣ中抗原活化的Ｔ细胞活性，保留未活化Ｔ细胞对ＣｏｎＡ诱导的丝裂原反应，在培养ｄ３加入ＩＬ－２－ＰＥ４０比培养开始时加入对ＭＬＣ抑制作用强。结论ＩＬ－２－ＰＥ４０能够高度选择性抑制免疫活性Ｔ细胞，是ＩＬ－２Ｒ靶向治疗中具有潜力的一种免疫抑制剂。     

In vitro effect of inosiplex on T lymphocytes. I. Influence on T cells with receptors for IgG (T gamma)

Inosiplex, a complex of inosine and 2-hydroxypropyldimethyl ammonium-4-(acetylamino)benzoate, 1:3 molar ratio, originally developed for antiviral use, is now under wider investigation because of its immunopotentiating properties. This compound can have some actions on T cells at various stages of differentiation, thus promoting an enhancement of their blastogenic responses to varied mitogenic agents (PHA, Con A, PWM, MLC, tetanus toxoid, and viral antigens). Our studies demonstrated that under the influence of inosiplex human peripheral blood T lymphocytes bearing Fc IgG receptors have an augmented receptor avidity for SRBC which result in an increased E active rosette formation, and that T cells preincubated with the drug at the appropriate concentrations express more Fc IgG receptors. Even though T gamma cells exert "in vitro" immunoregulatory properties, the increase in percentage of T gamma lymphocytes do not correlate with a potentiation of the Con A-induced suppressor activity of T cells. Moreover, the lymphocytes treated with the substance in the absence of Con A exert helper functions, increasing the mitogenic responses of the second culture PHA--treated lymphocytes. These data appear to suggest a pro-proliferative inosiplex-induced effect which could mask a concomitant suppressor cell induction.     

Effects of verrucarin A and roridin A, macrocyclic trichothecene mycotoxins, on the murine immune system

Verrucarin A (Ver A) and roridin A (Ror A), macrocyclic trichothecene mycotoxins, were examined for their immunomodulatory effects. Both mycotoxins were administered intraperitoneally at 0.35 mg/kg (1/2 the LD50) in CD-1 mice. Lymphocyte proliferation was studied on days 2, 4 and 7 after animals were dosed with Ver A. After day 2, no significant differences in [3H]thymidine (3H-TdR) incorporation were observed using concanavalin A (Con A), phytohemagglutinin (PHA), pokeweed mitogen (PWM) or lipopolysaccharide (LPS). On day 4 DNA synthesis induced by Con A, PHA and PWM was increased significantly. On day 7, PHA stimulation increased (p less than 0.001) above controls while Con A, PWM and LPS responses were not significantly different. The data indicated that Con A, PHA and PWM responses were time-dependent. Antibody production was evaluated by the hemolytic plaque assay; sheep red blood cells (SRBC) and Ver A were administered simultaneously, and Ver A was given 2 days after SRBC challenge. While spleen weights increased when Ver A was administered with SRBC or when the toxin was given 2 days after antigen, the antibody responses were not altered. In contrast, roridin A decreased PHA stimulation only on day 7 (p less than 0.05). There were no significant effects associated with the other mitogens. Antibody production did not differ significantly following administration of Ror A. Although Ver A and Ror A are equitoxic and structurally similar, their immunomodulatory properties for the given dose differ considerably. These different immunologic responses may be independent of other systemic toxic effects.     

Inhibition of lymphocyte response to mitogens by dipyridamole: Preliminary findings

Summary It has been recently noted that dipyridamole (DP) may be involved in certain immunological reactions, in addition to its antiplatelet action. In the present investigation the mitogenic response of human lymphocytes from three groups of subjects to 3 different lectins was examined. In both the experimental group treated over a short period and in the controls a highly significant decrease in the mean lymphocyte response to all 3 mitogens was noted following 3 days of DP administration. The response remained low after an additional 3 days of treatment. Discontinuation of drug administration was followed by a significant increase in response to two mitogens, concanavalin A (Con A) and pokeweed mitogen (PWM). The response to phytohaemagglutinin (PHA) extent only increased to a small, non-significant. No change in the mean mitogenic response was detected in the group undergoing long-term treatment. The mechanism by which DP alters lymphocyte activity is as yet unknown.     

Modulatory effect of isoprinosine on lymphocyte proliferative response under immunodepressive conditions

In the present work the effect of Isoprinosine on the mitogenic responses of T and B lymphocytes has been studied. We have found that Isoprinosine can enhance in vitro the response to Concanavalin A. This enhancement was more apparent in cell cultures showing an initially low blastogenic response. In low responses artificially induced by treatments in vivo with cyclophosphamide, our results indicate that Isoprinosine, administered in vivo, does not enhance the response to Con A of treated mice. However, addition of Isoprinosine (75 micrograms/ml) to cultures of spleen cells from mice previously treated with cyclophosphamide enhanced the suppressed response up to normal levels. Neither in vivo nor in vitro Isoprinosine treatments increased the response of lymphocytes to lipopolysaccharide, but usually inhibited the blastogenesis of B cells.     

Differences between rats and mice in the immunosuppressive activity of 2-methoxyethanol and 2-methoxyacetic acid.

Previous studies from this laboratory have demonstrated that 2-methoxyethanol (ME) and its principal metabolite 2-methoxyacetic acid (MAA) are immunosuppressive in young adult male Fischer 344 rats. In the present study, the immunosuppressive potential of ME and MAA was evaluated in young adult female Fischer 344 rats and C57BL/6J mice. Rats and mice were dosed by gavage with either ME or MAA in water, at dosages ranging from 50-400 mg/kg/day, for 10 consecutive days. Rats and mice were examined for alterations in body, spleen and thymus weights and mitogen-induced proliferation of splenic lymphocytes in vitro; separate groups were employed for the antibody plaque-forming cell (PFC) response to trinitrophenyl-lipopolysaccharide (TNP-LPS). Rats dosed at 100-400 mg/kg/day ME and rats dosed at 50-400 mg/kg/day MAA had decreased thymus weights in the absence of decreased body or spleen weights. Lymphoproliferative (LP) responses to concanavalin A (Con A), phytohemagglutinin (PHA), pokeweed mitogen (PWM) and Salmonella typhimurium mitogen (STM) were all reduced in rats treated with all dosages of ME. Rats treated with MAA displayed similar reductions in these LP responses except that the responses to PWM and STM in rats dosed at 50 mg/kg/day were not reduced. In contrast to the effects of ME and MAA on these end points in the rat, no thymic involution or suppression of LP responses were observed in mice dosed at 50-400 mg/kg/day. The PFC response to TNP-LPS was suppressed in rats dosed with either ME or MAA at dosages of 100-400 mg/kg/day. ME and MAA, however, failed to suppress the PFC response in mice immunized with TNP-LPS. These results indicate that unlike Fischer 344 rats, C57BL/6J mice are insensitive to the immunosuppressive effects of ME and MAA at the dosages employed in this study. Whether the different sensitivities of these two rodent species to ME- and MAA-induced immunosuppression are due to immunologic, pharmacokinetic or metabolic differences within each species remains to be determined.     

In vitro ozone exposure inhibits mitogen-induced lymphocyte proliferation and IL-2 production

Human blood mononuclear cells were exposed to ozone in vitro and thereafter analyzed for competence in mitogen-induced proliferation as well as IL-1 and IL-2 production. Proliferative responses induced by phytohemagglutinin (PHA), concanavalin A (Con A), and pokeweed mitogen (PWM) were all depressed in lymphocytes exposed to an ozone concentration of 1 ppm for 4-6 h. The response to PWM was most sensitive to the ozone effect (38% suppression); responses to Con A and PHA were suppressed to a lesser extent, 23% and 18%, respectively, and were not significantly different from each other. PWM responses were affected at an ozone concentration as low as 0.1 ppm; however, no suppression of Con A-induced proliferation was seen below 0.18 ppm or of PHA-induced proliferation below 0.5 ppm. When lymphocytes and monocytes were exposed separately to ozone and then mixed back with control air-exposed monocytes or lymphocytes, both cell types appeared to be affected and the functional defects caused by the pollutant were additive. Monocyte IL-1 production induced by endotoxin was not affected by ozone exposure, while surface expression of HLA-DR on exposed monocytes was reduced by 40% 24 h after exposure. Moreover, lymphocytes exposed to ozone produced 46% less IL-2 while expressing similar surface density of IL-2 receptors. Taken together, these results show that exposure to ozone has distinct adverse effects on lymphocytes and monocytes, both of which are important in local immune defenses in the lung.     

(Benzoylphenyl)piperidines: a new class of immunomodulators

A series of (benzoylphenyl)piperidines has been synthesized and evaluated for activity as immunomodulators. Several of these compounds show good activity in primary screening on the basis of the lymphocytes mitogenic response to Con A, PHA, and PWM. A chloro group in position 4 of the benzoyl moiety as well as an amino group (or a carbamate derivative) para to the piperidine nucleus seems to be essential for activity. The depicted compounds may be considered as the first examples of a new series of immunomodulators.     

三七皂苷的溶血性及免疫佐剂作用

目的:评价三七皂苷的溶血性及免疫佐剂作用。方法:以分光光度法测定三七皂苷对红细胞的溶血百分率;以卵白蛋白(OVA) 100μg、OVA 100μg加氢氧化铝2mg及OVA 100μg加不同剂量三七皂苷(50、100、200μg)分别免疫ICR小鼠,二次免疫(间隔14天)后,用MTT法检测Con A、PWM和PHA诱导脾淋巴细胞增殖反应,ELISA检测血清中的抗OVA抗体效价。结果:三七皂苷浓度为500和250mg/L时红细胞的溶血百分率分别为11.6％和3.6％;OVA加三七皂苷100μg免疫组小鼠Con A、PWM和PHA诱导的脾淋巴细胞增殖反应显著高于OVA对照组(P<0.01);OVA加三七皂苷(50、100、200μg)免疫细小鼠血清中抗OVA抗体效价高于OVA对照组(P<0.01)。结论:三七皂苷具有免疫佐剂活性及较低的溶血性。     

Carbofuran suppresses T-cell-mediated immune responses by the suppression of T-cell responsiveness, the differential inhibition of cytokine production, and NO production in macrophages

The effects of carbofuran (2,3-dihydro-2,2-dimethyl-7-benzo-furanol N-methylcarbamate) on the functions of T cells in splenocytes and peritoneal macrophages were examined in view of T-cell-mediated immune response (CMIR) in male C57BL/6 mice. Intraperitoneal administration of carbofuran (0.075, 0.15 and 0.3 mg/kg body weight) resulted in significant suppression of delayed type hypersensitivity (DTH), indicating that it caused the suppression of CMIR. Carbofuran decreased Concanavalin A (Con A)- and alloantigen-induced proliferation, and interleukin (IL)-2 production of splenocytes. In vitro addition of rIL-2 could not completely restore the suppressed T-cell proliferation, and IL-2-induced proliferation of Con A-activated splenocytes was also suppressed, which implied that carbofuran caused defects in IL-2 production and responsiveness of splenocytes to IL-2, leading to the suppression of T-cell proliferation. Con A-induced production of interferon-gamma (IFN-gamma) was significantly suppressed by carbofuran, while that of IL-4 was not affected. The production of transforming growth factor-beta from splenocytes was also significantly inhibited by carbofuran. Judging from these results, carbofuran might directly suppress the cytokine production in T helper 1 (Th1) cells. In addition, IFN-gamma-induced production of nitric oxide (NO) in macrophages was also inhibited by carbofuran, which might be one of the important mechanisms of carbofuran-induced CMIR suppression in mice. Collectively, the present study suggests that carbofuran might suppress CMIR through the suppression of T-cell responsiveness, IFN-gamma production in Th1 cells, and NO generation in macrophages.     

Elucidation of cellular targets responsible for tetrachlorodibenzo-p-dioxin (TCDD)-induced suppression of antibody responses: II. The role of the T-lymphocyte

Various immunological assays have been applied by our laboratory in an attempt to assess the role of the T-cell in the TCDD-induced suppression of the antibody response by murine B6C3F1 splenic lymphocytes. Animals were treated in vivo (via gavage) with 1.0 microgram/kg TCDD in corn oil for 5 days before in vitro analysis of splenocyte immunocompetence and T-cell function. To study the effects on T-helper cell function, alterations in the proliferative responses of T-cells following TCDD exposure were investigated. Results show no significant difference in [3H]thymidine uptake between vehicle- and TCDD-treated whole splenocytes 24 h after in vitro stimulation with the T-cell mitogen Con A. This is consistent with the finding that IL-2 production at either 24 or 48 h after Con A stimulation of TCDD-treated lymphocytes was not significantly different from that of vehicle-treated controls. The possibility of the induction of a suppressor T-cell by TCDD was also investigated. Titration of T-cells from TCDD-treated mice into naive splenocyte cultures did not suppress the humoral response to either a T-dependent (SRBC) or a T-independent (DNP-Ficoll) antigen. In contrast, titration of cells stimulated in vitro with Con A for 48 h (a positive control for the induction of a suppressor T-cell) inhibited humoral responses of naive cells to both types of antigen. Likewise, T-cells plus macrophages from TCDD-treated mice did not suppress the in vitro humoral responsiveness of naive B-cells plus macrophages to a T-independent antigen (DNP-Ficoll). These results would indicate that an alteration in T-cell function following TCDD exposure does not play a role in the suppression of the antibody response elicited by antigen stimulation of murine B6C3F1 splenocytes.     

Effects and mechanisms of melatonin on inflammatory and immune responses of adjuvant arthritis rat

AIM: To study the effects of melatonin on inflammatory and immune responses and its mechanisms. METHODS: The model of adjuvant-induced arthritis (AA) rat was induced by Freund's complete adjuvant (FCA); the thymocyte proliferation and IL-2 production were assayed by 3-(4,5-2dimethylthiazal-2yl)2,5-diphenyltetrazoliumbromide (MTT) and activated mouse splenocytes proliferation, respectively; cAMP and methionine-enkephalin (Met-Enk) level were determined by competitive protein binding assay (CPBA) and radioimmuno-assay, respectively. RESULTS: There was a marked inflammatory response in AA model, which was accompanied by the decreases of thymocyte proliferation and IL-2 production simultaneously. The prophylactic and therapeutic administration of melatonin (1, 10 and 100 microg kg(-1), ig x 7 days) inhibited the inflammatory response and enhanced thymocytes proliferation and IL-2 production significantly in AA rats. In vitro, melatonin, at the concentrations of 10(-7) and 10(-6) mol l(-1) could enhance the thymocyte proliferation in AA rats. The cAMP level stimulated by forskolin (F, a selective adenylate cyclase [AC] activator) in AA rats was higher than that in the control groups. Melatonin (10(-10) or 10(-6) mol l(-1)) had down-regulation on the above increased cAMP levels, which could be abolished by pertussis toxin (PT). Meanwhile, the decrease of thymocyte proliferation in AA rats had a marked relation with the decrease of Met-Enk level in these thymocytes, melatonin (10(-10) or 10(-6) mol l(-1)) could markedly enhance the Met-Enk level, which were blocked by nifedipine, a Ca2+ channel antagonist. CONCLUSIONS: Melatonin possesses anti-inflammatory and immunoregulatory actions, the G protein-AC-cAMP transmembrane signal and Met-Enk release in thymocyte are important mechanisms of this action.     

段木栽培及袋栽灵芝多糖对体外培养小鼠脾淋巴细胞增殖活性的比较

目的 比较段木栽培灵芝多糖(wood-cultured Ganoderma lucidum polysaccharides, GL-PS-WC) 及袋栽灵芝多糖(bag-cultured Ganoderma lucidum polysaccharides, GL-PS-BC)对体外培养小鼠脾淋巴细胞增殖活性的影响,探讨袋栽灵芝多糖替代段木栽培灵芝多糖的可能性。 方法检测两种灵芝多糖对混合淋巴细胞培养(MLC)反应的影响;观察对刀豆蛋白A (Con A)、细菌脂多糖(LPS)诱导淋巴细胞增殖的影响以及对环孢素A (CsA)、丝裂霉素C(Mit C)、足叶乙苷(VP-16) 等抑制MLC反应的影响。结果当质量浓度为0.2～12.8 mg·L^-1时,两种灵芝多糖均可促进MLC反应,增强Con A或LPS诱导的淋巴细胞增殖,并拮抗CsA, Mit C或VP-16对MLC反应的抑制作用。未发现两种多糖之间有显著性差异。结论GL-PS-WC及GL-PS-BC对体外培养脾淋巴细胞的增殖活性有类似作用。     

Systemic immunotoxicity in AJ mice following 6-month whole body inhalation exposure to diesel exhaust

The purpose of these studies was to determine the effects of subchronic diesel exposure on indicators of systemic immunity in mice. AJ mice were exposed daily for 6 months (6 h/day) to atmospheres containing one of four concentrations (30, 100, 300, and 1000 microg/m(3)) of diluted diesel exhaust (DE) in whole body exposure chambers. The effects of DE were compared to chamber exposure controls receiving fresh air. DE was assessed for effects on systemic immunity by measuring the proliferative response of spleen cells following stimulation with T cell (phytohemagglutinin, or PHA) or B cell (lipopolysaccharide, or LPS) mitogens. The results showed that DE at all exposure levels suppressed the proliferative response of T cells. B cell proliferation was increased at 30 microg/m(3) and was unaffected at the 100, 300, and 1000 microg/m(3) exposures. Polycyclic aromatic hydrocarbons (PAHs) are known to suppress spleen cell mitogenic responses, and it has been hypothesized by several groups that PAHs and perhaps benzo(a)pyrene (BaP)-quinones (BPQs) may be responsible for the effects of DE or diesel exhaust particles (DEP). Therefore, a second purpose of these studies was to determine the effects of in vitro BPQs on AJ mouse spleen cell mitogenic responses and compare to DE in preliminary studies. Unlike DE, BPQs were found to increase T cell proliferation. In addition, analysis of chamber atmospheres showed that there was little if any PAH and BPQs in DE. Therefore, these results demonstrate that because of the absence of BPQs in DE, they are likely not responsible for the immunosuppressive effect of DE on murine spleen cell responses.     

Effects of Fructus Ligustri Lucidi Extracts on Concanavalin A-Stimulated Proliferation of Isolated Murine Splenocytes

Fructus Ligustri Lucidi (FLL), the fruit of Ligustrum lucidum Ait., was fractionated into petroleum ether (FLL-Pe), chloroform (FLL-Ch), butanol (FLL-Bu) and aqueous (FLL-Aq) fractions. The effects of FLL fractions and oleanolic acid (OLA), an active ingredient of FLL, on concanavalin A (Con A)-stimulated proliferation of murine splenocytes were examined under both in vitro and ex vivo conditions. In vitro administration of FLL-Pe could produce an immunostimulatory effect, as evidenced by the significant enhancement of the Con A-stimulated mitogenic response of splenocytes in culture. While FLL-Ch and OLA did not produce any detectable effect on the mitogenic response, FLL-Bu and FLL-Aq inhibited the in vitro ConA-stimulated splenocyte proliferation. In ex vivo experiments, pretreatment with FLLPe, FLL-Ch or OLA was found to enhance the extent of Con A-stimulated splenocyte proliferation to a varying degree as assessed under in vitro conditions, with FLL-Pe being more potent. The ensemble of results indicates that both FLL-Pe and FLL-Ch were able to produce immunostimulatory action under ex vivo assay conditions, but only FLL-Pe produced a similar effect under in vitro conditions. The immunostimulatory action produced by FLL-Pe could not be fully explained by the presence of OLA.     

Effects of Tremella polysaccharides on immune function in mice

It was found in vitro that Tremella polysaccharides (TP) (50, 100, 150 and 200 micrograms/ml) augmented lymphocyte proliferation induced by Con A and did not antagonize the suppressive effect of hydrocortisone on lymphocyte proliferation. In vivo TP promoted the plaque-forming cell (PFC) response to SRBC in mice. TP 50 and 100 mg/kg ip for 5 d produced 77.6% and 81.8% increases in PFC response respectively. At the doses of 150 and 200 micrograms/ml, TP decreased the interleukin 2 (IL-2) activities in the supernatant of culture media of mouse spleen cells. TP (50 micrograms/ml) enhanced the lymphocyte proliferation induced by Con A and increased the PFC response to SRBC by 47.1% in 14-month-old mice.     

Stemucronatoside K, a novel C(21) steroidal glycoside from Stephanotis mucronata, inhibited the cellular and humoral immune response in mice

Stephanotis mucronata (Blanco) Merr. has been used for rheumatoid arthritis in Chinese folk herb medicine. Guided by bioactive test, a novel potent immunosuppressive C(21) steroidal glycoside stemucronatoside K (SMK) was isolated from this plant. Its structure was elucidated on the basis of the chemical evidence and extensive spectroscopic methods. We investigated the immunosuppressive effects of SMK in vitro and in vivo. SMK significantly suppressed concanavalin A (Con A)- and lipopolysaccharide (LPS)-stimulated splenocyte proliferation in vitro in a concentration-dependent manner. ICR mice were immunized subcutaneously with OVA on the first day and administered intraperitoneally with SMK at the doses of 2.5, 5, and 10 mg/kg once daily for 10 days. At 24 h after the last administration, mitogen- and OVA-stimulated splenocyte proliferation, the levels of cytokines from splenocytes, and specific antibody titers in serum were measured. SMK significantly inhibited Con A-, LPS- and OVA-induced splenocyte proliferation in the immunized mice in a dose-dependent manner. OVA-specific IgG, IgG1, and IgG2b antibody titers were significantly reduced by SMK compared with the control group. SMK also significantly decreased OVA-induced interleukin-2 (IL-2), interferon-gamma (IFN-gamma), and IL-4 production from splenocytes in the OVA-immunized mice. These results demonstrated that SMK could suppress the cellular and humoral immune response in mice. This study provided evidence to understand the therapeutic effects of S. mucronata and an immunosuppressive natural product compound to further researches to be developed as immunosuppressant.     

Stress and immune responses. II. Identification of stress-sensitive cells in murine spleen cells

The influences of restraint stress on the functions of T cells, B cells and adherent cells in antibody responses were investigated. Antibody response against sheep red blood cells (SRBC), a T cell-dependent antigen, in cultured splenocytes from restrained mice was reduced to about 40-50% of that from the control mice. Addition of normal T cells to these cultures, however, restored the suppressed response. Moreover, helper T cell activities were lowered in restrained mice. On the other hand, suppressor T cell activities induced by both concanavalin A (Con A) and SRBC were significantly decreased in restrained mice. However, the antibody responses to T cell-independent antigens in stressed mice were approximately 40% higher than the control response. These enhancement were also observed in T cell-depleted splenocytes. Polyclonal antibody response induced by lipopolysaccharide (LPS) was increased in stressed mice. Antigen presenting cell activities were little influenced by restraint stress. Proliferative response to Con A, but not that to LPS, was suppressed in splenocytes from restrained mice. These results suggest that both helper and suppressor activities of T cells are suppressed, but B cell activity is rather enhanced in splenocytes from restrained mice.     

Brazilein, an important immunosuppressive component from Caesalpinia sappan L

Caesalpinia sappan has been shown to have interesting immunosuppressive properties. Its heartwood has long been used in Chinese medicines for treating a variety of immune-mediated pathology and inflammatory disease. The purpose of this work was to evaluate the immunocompetence effects of brazilein on mice lymphocytes in vitro and in vivo. The results showed that brazilein and Caesalpinia sappan ethanol extract (SME) could distinctly inhibit the proliferation of T lymphocyte stimulated by Concanavalin A (Con A) and the proliferation of B lymphocyte stimulated by lipopolysaccharides (LPS), and brazilein could suppress mice humoral immune response by plaque forming cell (PFC) test. In addition, immune organs (thymus and spleen) in mice treated with brazilein were notably atrophied and weight loss in vivo (intraperitoneal injection, i.p.). In attempting to investigate the mechanisms of the immunosuppressive activity of brazilein, we discovered that brazilein can induce apoptosis in mice spleen lymphocytes by flow cytometry analysis and DNA fragmentation assay, which may be one of the pathways that brazilein inhibited immunocompetence of mice lymphocytes.