A Randomized Controlled Trial of the Effects of Mindfulness-Based Stress Reduction (MBSR[BC]) on Levels of Inflammatory Biomarkers Among Recovering Breast Cancer Survivors.

PURPOSE: The purpose of this substudy of a large randomized controlled trial was to evaluate the efficacy of the Mindfulness-Based Stress Reduction (Breast Cancer) (MBSR[BC]) program compared to usual care (UC) in normalizing blood levels of pro-inflammatory cytokines among breast cancer survivors (BCS). METHOD: A total of 322 BCS were randomized to either a 6-week MBSR(BC) program or a UC. At baseline and 6 and 12 weeks, 10 ml of venous blood and demographic and clinical data were collected and/or updated. Plasma cytokines (interleukin [IL]-1ß, IL-6, IL-10, tumor necrosis factor [TNF] α, transforming growth factor [TGF] ß1, soluble tumor necrosis factor receptor [sTNFR] 1) were assayed. Linear mixed models were used to assess cytokine levels across three time points (baseline and 6 and 12 weeks) by group (MBSR[BC] vs. UC). RESULTS: Of the six measured cytokines, three were nondetectable at rates greater than 50% (IL-10, IL-1ß, TGF-ß1) and, because of overall low prevalence, were not analyzed further. For the remaining cytokines (TNFα, IL-6, sTNFR1), results showed that TNFα and IL-6 increased during the follow-up period (between 6 and 12 weeks) rather than during the MBSR(BC) training period (between baseline and 6 weeks), while sTNFR1 levels did not change significantly across the 12-week period. CONCLUSIONS: Study results suggest that MBSR(BC) affects cytokine levels in BCS, mainly with increases in TNFα and IL-6. The data further suggest that B-cell modulation may be a part of immune recovery during breast cancer management and that increases in TNFα and IL-6 may be markers for MBSR(BC)-related recovery.

Δ(9)-Tetrahydrocannabinol (THC) enhances lipopolysaccharide-stimulated tissue factor in human monocytes and monocyte-derived microvesicles.

BACKGROUND: Immunomodulatory effects in humans of Δ(9-)Tetrahydrocannabinol (THC), the psychoactive component of marijuana are controversial. Tissue factor (TF), the activator of the extrinsic coagulation cascade, is increased on circulating activated monocytes and is expressed on microvesicles released from activated monocytes during inflammatory conditions, which perpetuate coagulopathies in a number of diseases. In view of the increased medicinal use of marijuana, effects of THC on human monocytes and monocyte-derived microvesicles activated by lipopolysaccharide (LPS) were investigated. FINDINGS: Peak levels of TF procoagulant activity developed in monocytes or microvesicles 6 h following LPS treatment and were unaltered by THC. After 24 h of LPS stimulation, TF activity declined in control-treated or untreated cells and microvesicles, but persisted with THC treatment. Peak TF protein occurred within 6 h of LPS treatment independent of THC; by 24 h, TF protein declined to almost undetectable levels without THC, but was about 4-fold greater with THC. Steady-state TF mRNA levels were similar up to 2 h in the presence of LPS with or without THC, while 10-fold greater TF mRNA levels persisted over 3-24 h with THC treatment. Activation of MAPK or NF-κB pathways was unaltered by THC treatment and inflammatory cytokine IL-6 levels were unchanged. In contrast, TNF and IL-8 levels were enhanced by 20-50 %. CONCLUSIONS: THC enhances TF expression in activated monocytes resulting in elevated procoagulant activity. Marijuana use could potentiate coagulopathies in individuals with chronic immune activation such as HIV-1 infection or inflammatory bowel disease.

Δ(9)-Tetrahydrocannabinol treatment during human monocyte differentiation reduces macrophage susceptibility to HIV-1 infection.

The major psychoactive component of marijuana, Δ(9)-tetrahydrocannabinol (THC), also acts to suppress inflammatory responses. Receptors for THC, CB1, CB2, and GPR55, are differentially expressed on multiple cell types including monocytes and macrophages, which are important modulators of inflammation in vivo and target cells for HIV-1 infection. Use of recreational and medicinal marijuana is increasing, but the consequences of marijuana exposure on HIV-1 infection are unclear. Ex vivo studies were designed to investigate effects on HIV-1 infection in macrophages exposed to THC during or following differentiation. THC treatment of primary human monocytes during differentiation reduced HIV-1 infection of subsequent macrophages by replication competent or single cycle CCR5 using viruses. In contrast, treatment of macrophages with THC immediately prior to or continuously following HIV-1 exposure failed to alter infection. Specific receptor agonists indicated that the THC effect during monocyte differentiation was mediated primarily through CB2. THC reduced the number of p24 positive cells with little to no effect on virus production per infected cell, while quantitation of intracellular viral gag pinpointed the THC effect to an early event in the viral life cycle. Cells treated during differentiation with THC displayed reduced expression of CD14, CD16, and CD163 and donor dependent increases in mRNA expression of selected viral restriction factors, suggesting a fundamental alteration in phenotype. Ultimately, the mechanism of THC suppression of HIV-1 infection was traced to a reduction in cell surface HIV receptor (CD4, CCR5 and CXCR4) expression that diminished entry efficiency.

Baseline immune biomarkers as predictors of MBSR(BC) treatment success in off-treatment breast cancer patients.

Researchers focused on patient-centered medicine are increasingly trying to identify baseline factors that predict treatment success. Because the quantity and function of lymphocyte subsets change during stress, we hypothesized that these subsets would serve as stress markers and therefore predict which breast cancer patients would benefit most from mindfulness-based stress reduction (MBSR)-facilitated stress relief. The purpose of this study was to assess whether baseline biomarker levels predicted symptom improvement following an MBSR intervention for breast cancer survivors (MBSR[BC]). This randomized controlled trial involved 41 patients assigned to either an MBSR(BC) intervention group or a no-treatment control group. Biomarkers were assessed at baseline, and symptom change was assessed 6 weeks later. Biomarkers included common lymphocyte subsets in the peripheral blood as well as the ability of T cells to become activated and secrete cytokines in response to stimulation with mitogens. Spearman correlations were used to identify univariate relationships between baseline biomarkers and 6-week improvement of symptoms. Next, backward elimination regression models were used to identify the strongest predictors from the univariate analyses. Multiple baseline biomarkers were significantly positively related to 6-week symptom improvement. The regression models identified B-lymphocytes and interferon-γ as the strongest predictors of gastrointestinal improvement (p < .01), +CD4+CD8 as the strongest predictor of cognitive/psychological (CP) improvement (p = .02), and lymphocytes and interleukin (IL)-4 as the strongest predictors of fatigue improvement (p < .01). These results provide preliminary evidence of the potential to use baseline biomarkers as predictors to identify the patients likely to benefit from this intervention.

Lymphocyte recovery after breast cancer treatment and mindfulness-based stress reduction (MBSR) therapy.

OBJECTIVES: This randomized controlled trial was conducted to examine immune recovery following breast cancer (BC) therapy and evaluate the effect of mindfulness-based stress reduction therapy (MBSR) on immune recovery with emphasis on lymphocyte subsets, T cell activation, and production of T-helper 1 (Th1; interferon [IFN]-γ) and T-helper 2 (Th2; interleukin-4 [IL-4]) cytokines. METHOD: Participants who completed the study consisted of 82 patients diagnosed with Stage 0-III BC, who received lumpectomy and adjuvant radiation ± chemotherapy. Patients were randomized into an MBSR(BC) intervention program or a control (usual care) group. Immune cell measures were assessed at baseline and within 2 weeks after the 6-week intervention. The numbers and percentages of lymphocyte subsets, activated T cells, and Th1 and Th2 cells in peripheral blood samples were determined by immunostaining and flow cytometry. RESULTS: Immune subset recovery after cancer treatment showed positive associations with time since treatment completion. The B and natural killer (NK) cells were more susceptible than T cells in being suppressed by cancer treatment. Women who received MBSR(BC) had T cells more readily activated by the mitogen phytohemagglutinin (PHA) and an increase in the Th1/Th2 ratio. Activation was also higher for the MBSR(BC) group if <12 weeks from the end of treatment and women in MBSR(BC) <12 weeks had higher T cell count for CD4(+). CONCLUSION: MBSR(BC) promotes a more rapid recovery of functional T cells capable of being activated by a mitogen with the Th1 phenotype, whereas substantial recovery of B and NK cells after completion of cancer treatment appears to occur independent of stress-reducing interventions.

Cannabinoid 2 (CB2) receptor involvement in the down-regulation but not up-regulation of serum IgE levels in immunized mice.

Marijuana cannabinoids such as Δ(9)-tetrahydrocannabinol (THC) have been shown in experimental systems to bias T helper immunity towards Th2 and away from Th1. This effect if broadly applicable to humans could have important implications in Th2-mediated diseases such as allergy. In the current study, we examined the effect of cannabinoids on serum immunoglobulin IgE levels in immunized mice and also examined the role of cannabinoid receptors in the response. The method involved pre-injecting mice with cannabinoid receptor agonists and antagonists followed 18-24 h later with an immunizing injection with two different antigen/adjuvant combinations. This treatment was followed 2-3 weeks later with a booster injection of antigen and the subsequent bleeding of mice 1-2 weeks later for serum immunoglobulin analysis by ELISA. Our results showed that THC injection enhanced total IgE serum levels in response to antigen immunization even under conditions of deficient cannabinoid receptor 2 (CB2) and cannabinoid receptor 1 (CB1) activity and furthermore the increase in IgE was accompanied by a decrease in serum IgG2a. In addition, we observed that l-α-lysophosphatidyliniositol (LPI) increased serum IgE levels and that IgE levels were higher in CB2 deficient mice and suppressed by the CB2 agonist, Gp1a. These results suggest that in this IgE induction model in mice, non-selective cannabinoids such as THC increase IgE through receptors other than CB1 and CB2 but that CB2 receptors do play a suppressive role in the control of serum IgE levels.

Identification of transcription start sites and preferential expression of select CB2 transcripts in mouse and human B lymphocytes.

Marijuana cannabinoids, the endocannabinoids, and cannabinoid cell receptors have been shown to play important roles in immune regulation particularly as potent modulators of anti-inflammatory cytokines. The predominant cannabinoid receptor involved in this immune regulation is cannabinoid receptor 2 (CB(2)), which is predominantly expressed in B lymphocytes. However, the promoter region and mechanisms of CB(2) gene regulation are unknown in this immune cell type. Utilizing a combination of bioinformatics, 5' rapid amplification of cDNA ends (5' RACE), real-time reverse transcription-polymerase chain reaction, DNA sequencing, and luciferase reporter assays, we show that human B cells express one CB(2) transcript while mouse B cells express three CB(2) transcripts, with specific transcript selection occurring during B cell activation by lipopolysaccharide. Alignment of our sequenced RACE products to either the mouse or human genome, along with the GenBank submitted mRNA sequences, revealed that the transcripts we isolated contained previously unidentified transcriptional start sites (TSS). In addition, expression construct testing of the genomic region containing the TSSs of the mouse CB(2) exon 1 transcripts showed an eightfold increase of promoter activity over baseline. These data show for the first time that human B cells use only one TSS for CB(2) while mouse B cells use multiple TSSs and that the mouse TSSs are in a genomic area with promoter activity, thus suggesting the location of the gene promoter region. Defining these TSSs also provides clues to the various gene regulatory factors involved in the expression of CB(2) during B cell activation.

Randomized controlled trial of mindfulness-based stress reduction (MBSR) for survivors of breast cancer.

OBJECTIVES: Considerable morbidity persists among survivors of breast cancer (BC) including high levels of psychological stress, anxiety, depression, fear of recurrence, and physical symptoms including pain, fatigue, and sleep disturbances, and impaired quality of life. Effective interventions are needed during this difficult transitional period. METHODS: We conducted a randomized controlled trial of 84 female BC survivors (Stages 0-III) recruited from the H. Lee Moffitt Cancer and Research Institute. All subjects were within 18 months of treatment completion with surgery and adjuvant radiation and/or chemotherapy. Subjects were randomly assigned to a 6-week Mindfulness-Based Stress Reduction (MBSR) program designed to self-regulate arousal to stressful circumstances or symptoms (n=41) or to usual care (n=43). Outcome measures compared at 6 weeks by random assignment included validated measures of psychological status (depression, anxiety, perceived stress, fear of recurrence, optimism, social support) and psychological and physical subscales of quality of life (SF-36). RESULTS: Compared with usual care, subjects assigned to MBSR(BC) had significantly lower (two-sided p<0.05) adjusted mean levels of depression (6.3 vs 9.6), anxiety (28.3 vs 33.0), and fear of recurrence (9.3 vs 11.6) at 6 weeks, along with higher energy (53.5 vs 49.2), physical functioning (50.1 vs 47.0), and physical role functioning (49.1 vs 42.8). In stratified analyses, subjects more compliant with MBSR tended to experience greater improvements in measures of energy and physical functioning. CONCLUSIONS: Among BC survivors within 18 months of treatment completion, a 6-week MBSR(BC) program resulted in significant improvements in psychological status and quality of life compared with usual care.

CB(1) and CB(2) cannabinoid receptors mediate different aspects of delta-9-tetrahydrocannabinol (THC)-induced T helper cell shift following immune activation by Legionella pneumophila infection.

Legionella pneumophila infection of mice induces proinflammatory cytokines and Th1 immunity as well as rapid increases in serum levels of IL-12 and IFNgamma and splenic IL-12Rbeta2 expression. Delta-9-tetrahydrocannabinol (THC) treatment prior to infection causes a shift from Th1 to Th2 immunity and here we demonstrate that CB(1) and CB(2) cannabinoid receptors mediate different aspects of the shift. Using cannabinoid receptor antagonists and cannabinoid receptor gene deficient mice (CB(1) (-/-) and CB(2) (-/-)), we showed that both CB(1) and CB(2) receptors were involved in the THC-induced attenuation of serum IL-12 and IFNgamma. IFNgamma production is dependent upon signaling through IL-12Rbeta2 (beta2) and THC treatment suppressed splenic beta2 message; moreover, this effect was CB(1) but not CB(2)-dependent from studies with receptor antagonists and CB1(-/-) and CB2(-/-) mice. Furthermore, observed increases in IL-4 induced by THC, were not involved in the drug effect on beta2 from studies with IL-4 deficient mice. The GATA-3 transcription factor is necessary for IL-4 production and is selectively expressed in Th2 cells. GATA-3 message levels were elevated in spleens of THC-treated and L. pneumophila-infected mice and the effect was shown to be CB(2) but not CB(1)-dependent. Furthermore, GATA-3 regulatory factors were modulated in that Notch ligand Delta4 mRNA was decreased and Jagged1 increased by THC also in a CB2-dependent manner and splenic NFkappaB p65 was increased. Together, these results indicate that CB(1) and CB(2) mediate the THC-induced shift in T helper activity in L. pneumophila-infected mice, with CB(1) involved in suppressing IL-12Rbeta2 and CB(2) involved in enhancing GATA-3.

Suppression of dendritic cell activation by anthrax lethal toxin and edema toxin depends on multiple factors including cell source, stimulus used, and function tested.

Bacillus anthracis produces lethal toxin (LT) and edema toxin (ET), and they suppress the function of LPS-stimulated dendritic cells (DCs). Because DCs respond differently to various microbial stimuli, we compared toxin effects in bone marrow DCs stimulated with either LPS or Legionella pneumophila (Lp). LT, not ET, was more toxic for cells from BALB/c than from C57BL/6 (B6) as measured by 7-AAD uptake; however, ET suppressed CD11c expression. LT suppressed IL-12, IL-6, and TNF-alpha in cells from BALB/c and B6 mice but increased IL-1beta in LPS-stimulated cultures. ET also suppressed IL-12 and TNF-alpha, but increased IL-6 and IL-1beta in Lp-stimulated cells from B6. Regarding maturation marker expression, LT increased MHCII and CD86 while suppressing CD40 and CD80; ET generally decreased marker expression across all groups. We conclude that the suppression of cytokine production by anthrax toxins is dependent on variables, including the source of the DCs, the type of stimulus and cytokine measured, and the individual toxin tested. However, LT and ET enhancement or suppression of maturation marker expression is more related to the marker studied than the stimuli or cell source. Anthrax toxins are not uniformly suppressive of DC function but instead can increase function under defined conditions.

Cannabinoid receptor 2 (CB2) mediates immunoglobulin class switching from IgM to IgE in cultures of murine-purified B lymphocytes.

Marijuana cannabinoid treatment increases Th2 activity, and previous reports showed that B cells express the highest level of CB(2) mRNA relative to other immune cells, suggesting that cannabinoids play a critical role in B cell activation and maturation. We previously reported evidence of Th2 biasing and class switching in cannabinoid-treated and antigen-challenged mice. We now explore the possibility that cannabinoids directly influence B cell antibody class switching. Mouse splenic B cells were purified by negative selection and cultured with IL4 and anti-CD40 in the presence or absence of the nonselective cannabinoid agonist, CP55940, or the CB(1) selective cannabinoid agonist, methanandamide, and analyzed at different days by flow cytometry for surface expression of either IgM or IgE. Cells treated with CP55940 showed an increase in expression of IgE by day 5 in culture; methanandamide had no effect. CP55940 also induced an increase in secreted IgE in culture supernatants as analyzed by ELISA. In addition, CB(2) receptors were increased on B cells after stimulation with IL-4 and anti-CD40, and the class switching effect of CP55940 was attenuated by the CB(2) antagonist, SR144528. These results suggest that cannabinoids bias toward Th2-type immunity by directly inducing B cell class switching from IgM to IgE through a mechanism involving CB(2) receptors.

Therapeutic potential of cannabinoid-based drugs.

Cannabinoid-based drugs modeled on cannabinoids originally isolated from marijuana are now known to significantly impact the functioning of the endocannabinoid system of mammals. This system operates not only in the brain but also in organs and tissues in the periphery including the immune system. Natural and synthetic cannabinoids are tricyclic terpenes, whereas the endogenous physiological ligands are eicosanoids. Several receptors for these compounds have been extensively described, CB1 and CB2, and are G protein-coupled receptors; however, cannabinoid-based drugs are also demonstrated to function independently of these receptors. Cannabinoids regulate many physiological functions and their impact on immunity is generally antiinflammatory as powerful modulators of the cytokine cascade. This anti-inflammatory potency has led to the testing of these drugs in chronic inflammatory laboratory paradigms and even in some human diseases. Psychoactive and nonpsychoactive cannabinoid-based drugs such as Delta9-tetrahydrocannabinol, cannabidiol, HU-211, and ajulemic acid have been tested and found moderately effective in clinical trials of multiple sclerosis, traumatic brain injury, arthritis, and neuropathic pain. Furthermore, although clinical trials are not yet reported, preclinical data with cannabinoid-based drugs suggest efficacy in other inflammatory diseases such as inflammatory bowel disease, Alzheimer's disease, atherosclerosis, and osteoporosis.

Differential effects of Chlamydia pneumoniae infection on cytokine levels in human T lymphocyte- and monocyte-derived cell cultures.

Continuous cultures of human lymphocyte- and monocyte-derived cell lines were examined for levels of immunoregulatory cytokines important in resistance to the intracellular opportunistic bacterium Chlamydia pneumoniae (Cp), a ubiquitous pathogen widely disseminated in the population and hypothesized to be involved in chronic inflammatory diseases such as atherosclerosis and neurological diseases like multiple sclerosis and Alzheimer's disease. The results of this study showed that the continuous human T lymphocyte cell line MOLT-4 and the continuous monocytic cell line THP-1 were readily infected by Cp in vitro as shown by immunofluorescence microscopy for Cp lipopolysaccharide (LPS). The 16S rRNA expression determined by real-time RT-PCR increased rapidly after infection of either cell line with these bacteria. The THP-1 cells infected with Cp showed increased levels of the immunoregulatory cytokine IL-12 and also of TNFalpha and IL-10 compared to cultures stimulated with heat-killed Cp (KCp) or Escherichia coli LPS as a control. Stimulation of MOLT-4 cells with KCp or E. coli LPS also induced the Th1 cytokines IFNgamma and IL-12 and the Th2 cytokine IL-10, but infection with viable Cp induced higher Th1 cytokine levels. These results suggest that Cp infection induces a predominant Th1 cytokine profile by T cells, in addition to induction of TNFalpha by monocytes/macrophages. Such effects are likely involved in antibacterial immunity against Cp infection.

Role of Toll-like receptor 9 in Legionella pneumophila-induced interleukin-12 p40 production in bone marrow-derived dendritic cells and macrophages from permissive and nonpermissive mice.

The progression of Legionella pneumophila infection in macrophages is controlled by the Lgn1 gene locus, which expresses the nonpermissive phenotype in cells from BALB/c mice but the permissive phenotype in cells from A/J mice. Activation of dendritic cells and macrophages by L. pneumophila is mediated by the pathogen recognition receptor Toll-like receptor 2 (TLR2); furthermore, Legionella induces innate and adaptive immune cytokines by the MyD88-dependent pathway. TLR9 is coupled to MyD88 and mediates the production of interleukin-12 (IL-12) in dendritic cells infected with other facultatively intracellular pathogens. In the current study, L. pneumophila growth in dendritic cells from BALB/c and A/J mice was examined along with the role of TLR9 in the induction of IL-12 in these cells. Dendritic cells from both strains were nonpermissive for L. pneumophila intracellular growth, suggesting that the products of the Lgn1 gene locus that control intracellular growth in macrophages do not control the growth of Legionella in dendritic cells. In addition, chloroquine treatment suppressed IL-12 p40 production in response to Legionella treatment in dendritic cells and macrophages from BALB/c and A/J mice. Furthermore, the TLR9 inhibitor ODN2088 suppressed the Legionella-induced IL-12 production in dendritic cells from both mouse strains. These results suggest that L. pneumophila is similar to other intracellular bacteria in that it stimulates the production of immune-transitioning cytokines, such as IL-12, through activation of TLR9 and that this receptor provides a common mechanism for sensing these types of microbes and inducing innate and adaptive immunity.

Cannabinoid treatment suppresses the T-helper cell-polarizing function of mouse dendritic cells stimulated with Legionella pneumophila infection.

Marijuana cannabinoids, such as delta-9-tetrahydrocannabinoid (THC), suppress type 1 T-helper 1 (Th1) immunity in a variety of models, including infection with the intracellular pathogen Legionella pneumophila (Lp). To examine the cellular mechanism of this effect, bone marrow-derived dendritic cells (DCs) were purified from BALB/c mice and studied following infection and drug treatment. DCs infected in vitro with Lp were able to protect mice when injected prior to a lethal Lp infection; however, the immunization potential of the Lp-loaded cells along with Th1 cytokine production was attenuated by THC treatment at the time of in vitro infection. In addition, THC-treated and Lp-loaded DCs were poorly stimulated in culture-primed splenic CD4(+) T cells to produce interferon-gamma; however, this stimulating deficiency was reversed by adding recombinant interleukin (IL)-12p40 protein to the cultures. Moreover, THC treatment inhibited the expression of DC maturation markers, such as major histocompatibility complex class II and costimulatory molecules CD86 and CD40 as determined by flow cytometry and suppressed the Notch ligand, Del-ta4, as determined by reverse transcription-polymerase chain reaction. However, THC treatment did not affect other DC functions, such as intracellular killing of Lp, determined by colony-forming unit counts of bacteria, and Lp-induced apoptosis, determined by annexin V staining. In conclusion, the data suggest that THC inhibits Th1 activation by targeting essential DC functions, such as IL-12p40 secretion, maturation, and expression of costimulatory and polarizing molecules.

Addictive drugs and their relationship with infectious diseases.

The use of drugs of abuse, both recreationally and medicinally, may be related to serious public health concerns. There is a relationship between addictive drugs of abuse such as alcohol and nicotine in cigarette smoke, as well as illegal drugs such as opiates, cocaine and marijuana, and increased susceptibility to infections. The nature and mechanisms of immunomodulation induced by such drugs of abuse are described in this review. The effects of opiates and marijuana, using animal models as well as in vitro studies with immune cells from experimental animals and humans, have shown that immunomodulation induced by these drugs is mainly receptor-mediated, either directly by interaction with specific receptors on immune cells or indirectly by reaction with similar receptors on cells of the nervous system. Similar studies also show that cocaine and nicotine have marked immunomodulatory effects, which are mainly receptor-mediated. Both cocaine, an illegal drug, and nicotine, a widely used legal addictive component of cigarettes, are markedly immunomodulatory and increase susceptibility to infection. The nature and mechanism of immunomodulation induced by alcohol, the most widely used addictive substance of abuse, are similar but immunomodulatory effects, although not receptor-mediated. The many research studies on the effects of these drugs on immunity and increased susceptibility to infectious diseases, including AIDS, are providing a better understanding of the complex interactions between immunity, infections and substance abuse.

Role of cannabinoid receptors in Delta-9-tetrahydrocannabinol suppression of IL-12p40 in mouse bone marrow-derived dendritic cells infected with Legionella pneumophila.

Delta-9-tetrahydrocannabinol (THC) injection suppresses serum interleukin-12 (IL-12) levels in Legionella pneumophila-infected mice. Dendritic cells are a major producer of IL-12 and mouse, bone marrow-derived dendritic cell cultures produced high levels of the IL-12p40 following L. pneumophila infection. Treatment with THC suppressed this cytokine response in a concentration-dependent manner and the endocannabinoid, 2-arachidonoyolglycerol, less potently suppressed cytokine production. Dendritic cells expressed mRNA for cannabinoid receptor 1 (CB(1)), cannabinoid CB(2) receptor, and vanilloid receptor 1 (TRPV1) and the addition of the G(i) inhibitor, pertussis toxin, completely attenuated suppression induced by 3 and 6 muM THC but not by 10 muM THC. Furthermore, THC suppression was partially attenuated in dendritic cells from cannabinoid CB(1) receptor and CB(2) receptor knockout mice and in dendritic cells co-treated with THC and cannabinoid receptor antagonists. Cytokine suppression was not attenuated by pretreatment with the TRPV1 antagonist, capsazepine. These results suggest that THC-induced suppression of serum IL-12 is partly due to a suppression of IL-12 production by dendritic cells and that G(i) signaling and cannabinoid receptors, but not TRPV1, are involved in this suppressive effect.

Cannabinoid-induced immune suppression and modulation of antigen-presenting cells.

The study of marijuana cannabinoid biology has led to many important discoveries in neuroscience and immunology. These studies have uncovered a new physiological system, the endocannabinoid system, which operates in the regulation of not only brain function but also the regulation of the immune system. Studies examining the effect of cannabinoid-based drugs on immunity have shown that many cellular and cytokine mechanisms are suppressed by these agents leading to the hypothesis that these drugs may be of value in the management of chronic inflammatory diseases. In this report, we review current information on cannabinoid ligand and receptor biology, mechanisms involved in immune suppression by cannabinoids with emphasis on antigen-presenting cells, and preclinical and clinical models analyzing the therapeutic potential of cannabinoid-based drugs.

Epigallocatechin gallate modulates cytokine production by bone marrow-derived dendritic cells stimulated with lipopolysaccharide or muramyldipeptide, or infected with Legionella pneumophila.

The primary polyphenol in green tea extract is the catechin epigallocatechin gallate (EGCG). Various studies have shown significant suppressive effects of catechin on mammalian cells, either tumor or normal cells, including lymphoid cells. Previous studies from this laboratory reported that EGCG has marked suppressive activity on murine macrophages infected with the intracellular bacterium Legionella pneumophila (Lp), an effect mediated by enhanced production of both tumor necrosis factor-alpha (TNF-alpha) and gamma-interferon (IFN-gamma). In the present study, primary murine bone marrow (BM)-derived dendritic cells (DCs), a phagocytic monocytic cell essential for innate immunity to intracellular microorganisms, such as Lp, were stimulated in vitro with the microbial stimulant lipopolysaccharide (LPS) from gram-negative bacteria, the cell wall component from gram-positive bacteria muramyldipeptide (MDP) or infected with Lp. Production of the T helper cell (Th1)-activating cytokine, interleukin-12 (IL-12) and the proinflammatory cytokine, tumor necrosis factor-alpha (TNF-alpha),produced mainly by phagocytic cells and important for antimicrobial immunity, was determined in cell culture supernatants by enzyme-linked immunosorbent assay (ELISA). Treatment of the cells with EGCG inhibited, in a dose-dependent manner, production of IL-12. In contrast, enhanced production of TNF-alpha occurred in a dose-dependent manner in the DC cultures stimulated with either soluble bacterial product or infected with Lp. Thus, the results of this study show that the EGCG catechin has a marked effect in modulating production of these immunoregulatory cytokines in stimulated DCs, which are important for antimicrobial immunity, especially innate immunity. Further studies are necessary to characterize the physiologic function of the effect of EGCG on TNF-alpha and IL-12 during Lp infection, and the mechanisms involved.