Heligmosomoides bakeri antigen rescues CD4-positive T cells from glucocorticoid-induced apoptosis by Bcl-2 protein expression.

Heligmosomoides bakeri infection in mice is associated with a dominant CD4(+) T-cell response and with the activity of natural Treg cells with CD4(+) CD25(+) phenotype. The polarization of Th2 T-cell phenotype and the increase in the CD4(+) CD25(+) T cell population are regulated by glucocorticoids that induce apoptosis in CD4(+) CD25(-) T cells and inhibit apoptosis in CD4(+) CD25(+) T cells. However, exposure of mice to H. bakeri antigen induces a high glucocorticoid concentration in serum and a reduction in the number of CD4-positive; CD4(+) CD25(-) and CD4(+) CD25(+) apoptotic T cells in mesenteric lymph node cells. In this study to evaluate the in vitro effect of the anti-apoptotic property of H. bakeri antigen on T cells, apoptosis of these cells was induced by glucocorticoids-dexamethasone (Dex). Excretory-secretory (ES) antigen of the nematode prevented Dex-induced apoptosis in CD4-positive T cells with CD4(+) CD25(-) and CD4(+) CD25(High) phenotype by Bcl-2 protein expression. Contrary to the effect on CD4-positive T cells, survival of CD8(+) T cells was not connected with expression of Bcl-2 protein. This suggest that H. bakeri antigen modulates CD4-positive T cell sensitivity to glucocorticoid-induced apoptosis by induction of Bcl-2 protein.

Reduced apoptosis in BALB/c mice infected with Heligmosomoides polygyrus.

We evaluated levels of apoptosis and the immune response ex vivo in BALB/c mice infected with Heligmosomoides polygyrus. Cell proliferation, apoptosis and cytokine production were measured in mesenteric lymph nodes (MLN) without exposure to H. polygyrus antigens in culture. The inhibited apoptosis and cytokine production reported might reflect a state of cell hyporesponsiveness in the prepatent phase of infection. These changes were accompanied by changes in the percentage of CD4+ cells in MLN and popliteal lymph nodes (PLN). The prolonged reduction in apoptosis coexisted with induced cell proliferation, elevated TNF-alpha, IL-12p70, IFN-gamma, IL-6, IL-10 and TGF-beta synthesis, but lowered IL-4 and IL-2 levels. In the chronic phase of infection an increasing production of IFN-gamma, monocyte chemotactic protein-1 (MCP-1), IL-10 and TGF-beta with decreasing concentrations of other cytokines resulted in restored apoptosis. The cytokine response in serum showed moderate production of TNF-alpha, temporary involvement of IL-12p70, induction of IFN-gamma and IL-10 synthesis, as well as growing IL-6 and MCP-1 production. It is suggested that a synchronized synthesis of distinct cytokines is accompanied by different levels of inhibited apoptosis during the prepatent and chronic phases of H. polygyrus infection in BALB/c mice. We suggest that immunosuppression provoked by the nematode is not the outcome of parasite-induced apoptosis, but rather results from a hyporesponsiveness experienced by cells during H. polygyrus infection.

The role of TGF-beta in mice infected with Heligmosomoides polygyrus.

Hyporesponsiveness induced by Heligmosomoides polygyrus was quantified and the relationship between TGF-beta and inflammation was identified in BALB/c mice. The immune response and pathological changes modified by neutralization of TGF-beta were characterized in vivo. Nine and twelve days following infection, BALB/c mice were injected intraperitoneally with anti-TGF-beta (1,2,3) antibodies, isotype control antibodies or isosmotic solution. We assessed both Th1 and Th2 related cytokines production ex vivo and in vitro, IgA, the number of CD4+ cells, and eosinophils in the lamina propria and the villus : crypt ratio in the small intestine 6 weeks after infection. The pattern of cytokine production differed in the intestine, peritoneal fluid and serum. In mice infected with H. polygyrus the concentrations of IL-5, IL-12, TNF-alpha and IL-10 were raised in the intestine, but in serum the level of cytokines was diminished below the value observed in uninfected mice. The neutralization of TGF-beta converted the pattern of immune response induced by H. polygyrus. The elevation of cytokines in serum coincided with the reduction of cytokine concentration in the intestine or peritoneum. Neutralization of TGF-beta restored infiltration of eosinophils into the lamina propria of the intestine despite the low level of IL-5. We conclude that H. polygyrus infection suppresses the immune response through pathways involving TGF-beta production or activity and that the Th2 related immune response was not affected by neutralization.

A novel apoptosis-like pathway, independent of mitochondria and caspases, induced by curcumin in human lymphoblastoid T (Jurkat) cells.

We have shown previously [E. Sikora, A. Bielak-Zmijewska, K. Piwocka, J. Skierski, and E. Radziszewska (1997) Biochem. Pharmacol. 54, 899-907] that curcumin prevents formation of oligonucleosomal DNA fragmentation in rat thymocytes and human leukemic T lymphocytes (Jurkat cells) induced to undergo apoptosis. In this paper we show that 50 microM curcumin by itself induces cell death in Jurkat cells, but its symptoms differ from those observed after a short ultraviolet (uv) irradiation. Ultraviolet-irradiated Jurkat cells displayed typical symptoms of apoptosis: morphological changes, internucleosomal and high-molecular-weight DNA fragmentation, formation of sub-G1 fractions in DNA content frequency histograms, and dissipation of the mitochondrial transmembrane electric potential (Delta psi). In contrast, curcumin-treated Jurkat cells exhibited DNA splitting into high-, but not low-, molecular-weight fragments. These cells retained their high mitochondrial Delta psi, and the content of Ca2+ in endoplasmic reticulum stores remained at the level typical for untreated cells. The frequency of opening of the mitochondrial permeability transition pores in curcumin-treated cells was decreased compared to the controls, whereas uv irradiation made these pores completely open. Curcumin did not produce any change in the activity of caspase-3, whereas uv irradiation considerably activated this protease. The morphology of curcumin-treated cells displayed chromatin condensation, which was insensitive to the caspase inhibitor z-VAD-fmk, but no formation of typical apoptotic bodies, as was the case after uv irradiation. In contrast to uv-irradiated cells, curcumin-treated Jurkat cells considerably increased the level of Bcl-2. It is concluded that the programmed cell death induced by curcumin in Jurkat cells differs from "classical" by the lack of mitochondrial depolarization and of the involvement of caspases.

Sensitivity of mouse lymphoid and nonlymphoid organs to Silesian air pollutants.

The toxic effect of Silesian air pollutants to mouse organs was examined. Histological changes were found in the examined lymphoid organs (thymus, spleen) as well nonlymphoid organs (liver, kidneys). The alterations in weight indexes of lymphoid organs were also observed. Considerable changes in cellularity, weight index, and histology of the thymus in the mice exposed to air pollutants suggest the atrophy of this organ, which may lead to extrathymic T-cell differentiation and even acceleration of thymocytes maturation, which may lead to certain allergic or auto-immune pollutants of all investigated mouse organs in the following order: thymus, liver, kidneys, and spleen.

[Organ cytotoxicity of selected polycyclic aromatic hydrocarbons in mice]. / Cytotoksycznosc narzadowa wybranych policyklicznych weglowodorów aromatycznych (WWA) u myszy.

The cytotoxic effects of some PAHs: DMBA, 3-MC and B(a)P on the lymphatic organs, liver and kidney of mice have been investigated. These PAHs in doses of 100 mg/kg were dissolved in 0.5 ml 20% DMSO and were given intraperitoneally in female mice Balb/c. After 7 days, organs weight, cellularity in lymphoid organs and tissue structure of liver and kidney were analyzed. The greatest effect of DMBA was observed on cellularity of spleen. 3-MC and B(a)P caused significant hepatotoxic and nephrotoxic changes. 3-MC induced focal destruction of hepatocytes and sometimes--irregular mitotic figures (c-mitosis). After B(a)P administration in liver cells were mainly observed the changes in distribution of interphase nucleolar organizer region (AgNOR). In kidney--irregular glomeruli and tubuli after 3-MC and B(a)P were noted. The above results may indicate that the cytotoxic effects of PAHs depend on the type of compound administered.

Thymus-directed immunotoxicity of airborne dust particles from Upper Silesia (Poland) under acute extrapulmonary studies in mice.

Industrial air pollutants from Upper Silesia, Poland, contain over 250 polycyclic and heterocyclic aromatic hydrocarbons and heavy metals, including mutagenic and carcinogenic chemicals that have been shown to form DNA adducts. Over 4 million habitants of Silesia are permanently exposed to the industrial pollution by pulmonary and dermal routes and by contaminated food and water. These chemicals, when examined separately in animals models, were proven immunotoxic. We studied the extrapulmonary immunotoxic potential of a typical mixture of Silesian filter-suspended matter from a selected area, over a specific season and time period. Early changes in the immune system were analyzed in BALB/c mice exposed ip to acute doses of 20-330 mg dust mixture/kg body weight (0.06-1.0 LD50). No major changes were noted for weight and the cellularity of spleen, liver and kidneys. However, dramatic decrease in thymus weight index and thymocyte cell count were noted as early as 24-72 h postexposure, which correlated with almost complete depletion of immature, double-positive CD4+CD8+ thymocytes. Changes in spleen were less profound; however, increased depletion of B cells over T cells was noted at high doses of the suspended matter. Exposure to the airborne dust also decreased cytokine production by spleen cells, such as interferon-gamma (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha). Overall, a single exposure to Silesian dust, even at the relatively low 0.06 LD50 dose, affected lymphokine production, suppressed B-cell proliferative response, and depleted thymuses of immature, double-positive CD4+CD8+ cells. A chemical synergism is suspected. To our knowledge, none of the known components of Silesian suspended matter, when examined as a single chemical, was shown to exert such a profound biological effect.

Different T-cell activation by streptozotocin and Freund's adjuvant in popliteal lymph node (PLN).

A popliteal lymph node (PLN) test was further validated for predictive screening of autoimmunity-inducing drugs. Autoimmune-like T-cell activation of streptozotocin (STZ) was compared with the effect of Freund's complete adjuvant (FCA), injected locally into the foot pad of BALB/c mice. Early cell activation in enlarged PLN was monitored by flow cytometry. Injection of both STZ and FCA markedly increased the absolute PLN cell number as well as specific T-helper (CD4+), T-suppressor/cytotoxic (CD8+), and B (Ig+) subsets. However, quantitative analysis of early T-cell activation revealed important differences between STZ-induced PLN reaction and FCA-related lymphoproliferation. At 72 h, the number of cells stained with anti-early activation marker (EAM+; CD69+) increased over 10 times in STZ-enlarged nodes and only 3 times in the FCA-inflamed nodes. Furthermore, different cytometric profiles were noted for STZ-activated and FCA-activated cells stained with anti-interleukin-2 receptor (IL-2R) (CD25+). The data suggest the applicability of early cytometric screening of enlarged PLN for predictive analysis detection of chemicals inducing an autoimmune-like reaction.

Exogenous melatonin modifies the circadian rhythm but does not increase the level of some immune parameters in the chicken.

The effect of daily injection of the pineal hormone melatonin and naltrexone, an opioid antagonist, on the circadian rhythm and the level of immune parameters (plaque forming cell [PFC] number, serum agglutinin titer, lymphoid gland weight, total white blood cells (WBC) and their fraction number, and serum lysozyme [LZ] content) was examined in White Leghorn cockerels and female BALB/c mice kept in LD 12:12. Animals were immunized ip with sheep red blood cells (SRBC) to stimulate their immune system. Subcutaneous injections of melatonin, naltrexone, or both drugs together were made 2 hr before the end of light, for 4 or 5 days, beginning on the day of immunization. The day following the fifth injection, chickens were sacrificed over a 24 hr period every 4 hr (experiment I) or twice daily, i.e., at the beginning of light and dark phases (experiment II). Mice were killed on the day following the fourth injection at the beginning of light, and splenic PFC number was determined (experiment III). In experiment I, the existence of the diurnal rhythm was evaluated by cosinor analysis. Melatonin injections entrained the circadian rhythm in anti-SRBC serum agglutinins, but it did not influence circadian rhythmicity in other parameters examined. The circadian rhythm in total WBC number and their fractions was entrained by naltrexone treatment. Melatonin injections did not affect either the diurnal mean of parameters examined or the weight of lymphoid organs. Splenic PFC number in chickens was diminished by both melatonin and naltrexone injections, whereas in mice it was increased by melatonin, and naltrexone antagonized that effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Staphylococcal lipase affects phagocytosis of Staphylococcus aureus by human granulocytes and monocytes.

The rate of immunological and non-immunological phagocytosis of staphylococci by lipase pre-treated human granulocytes and monocytes was compared. It was found that the effect of this enzyme on two types of cells is opposite. Lipase decreases phagocytosis by granulocytes and increases by monocytes. The revealed differences between phagocytosing cells studied prompted us to investigate the influence of lipase on Fc receptors on these cells (rosette EA test). The different susceptibility of Fc receptors on non-activated phagocytes to lipase was found. This could be at least partially responsible for the difference observed between phagocytic activity of granulocytes (decreased) and monocytes (increased) pretreated with staphylococcal lipase. Inactivated enzyme showed a similar effect as active enzyme in the case of granulocytes. However, inactivated enzyme had no effect on rosette formation by lipase pretreated monocytes, indicating an enzymatic effect.

Zinc affects humoral and cellular response in mice.

The aim of the presented work was to elucidate whether supplementation with zinc affects the immunological response in BALB/c mice. Zinc was used as ZnCl2 in concentrations of 10(-4); 10(-5); 10(-6) M in PFC and migration-inhibition test. It was found that the numbers of anti-SRBC antibody-producing cells in mice injected with zinc were greater than in the control ones. This enhancement of PFC was proportional to the concentration of zinc. ZnCl2 itself inhibited target cell migration in concentration 10(-4) M but had no effect at 10(-5) and 10(-6) M. Zinc in all investigated concentrations promoted the action of suboptimal as well as optimal doses of PHA and enhanced target cell migration inhibition. It was determined that ZnCl2 in concentration 10(-4) M activated mouse lymphocytes for migration inhibitory factors production. We postulate that zinc may enhance the effectiveness of anti-infectious immunity.

Effect of azathioprine on the early stages of human lymphocyte activation.

The effect of azathioprine preincubation on the early stages of mitogenic stimulation of human blood lymphocytes and on spontaneous cell proliferation in vitro was investigated. This effect was measured by the method of 3H-thymidine incorporation in microcultures. The experiments demonstrated: decrease of suppression of lymphocyte stimulation by PHA in cultures preincubated with azathioprine and non restimulated after drug removal, significant reduction of inhibition of lymphocyte stimulation in cultures preincubated with azathioprine and restimulated by PHA after drug removal, a tendency to stimulate spontaneous proliferation in nonstimulated lymphocyte cultures preincubated with AZ and cultured in the absence of the drug, interference of PHA stimulation with the induction of suppression by azathioprine: stimulated lymphocytes are more sensitive to the suppressive effect of AZ, even in the early phase of cell proliferation.

Changes in the expression of SRBC receptors on human lymphocytes caused by azathioprine and puromycine.

The expression of human peripheral T lymphocyte receptors for sheep red blood cells in vitro was investigated. Changes in the expression of SRBC receptors were analysed in successive culture days depending on the stimulation of lymphocytes by PHA or Con A and the action of immunosuppressive agents, such as azathioprine and puromycine. The SRBC receptor variability of expression in cultures of whole peripheral blood lymphocytes was compared with that of T lymphocytes subpopulation isolated by the rosetting method. The experiments demonstrated: a) the appearance of different morphological E rosette types in cultures stimulated by plant mitogens, b) the inhibition of SRBC receptor expression by azathioprine and puromycine on lymphocytes from stimulated and non-stimulated cultures, c) higher sensitivity of SRBC receptors to immunosuppressive agents on cultured isolated T lymphocytes, d) the difference of azathioprine and puromycine action on the ability to form all types of E rosettes in stimulated and nonstimulated cultures.

Modulation of the humoral response in Pseudomonas aeruginosa-infected mice.

Kinetics of humoral anti-SRBC response in the host infected with Pseudomonas aeruginosa was investigated. In the course of experimental infection in CFW mice with 0.01 LD50 Pseudomonas aeruginosa 74 followed by immunization with SRBC, inhibition of PFC anti-SRBC production was observed for 5 days after infection. In the case of infection with 0.1 LD50 P. aeruginosa 74 stimulation of anti-SRBC PFC production was observed for 6 days after infection.