PHA-induced Lymphocyte Proliferation Research Articles

May be dysfunction of cellular immunity considered a sign of post-COVID syndrome?

Our aim was to study association between proliferative activity of peripheral blood lymphocytes after COVID, and developing post-COVID syndrome, and to determine whether the cell immunity dysfunction may be regarded as its marker. The retrospective cohort study involved 242 patients (56 males, 186 females, 18 to 85 years old) who contracted new coronavirus infection. Of them, post-COVID syndrome was diagnosed in 180 cases (duration over 3 months). The patients were classified by severity of clinical course of COVID (i.e., presence of acute respiratory disease and pneumonias), and PHA-induced blast transformation of lymphocytes. Along with PHA-induced response, we studied cyclooxygenase (COG)-producing cells by morphological method. Control group consisted of 200 healthy people without any features of coronavirus infection. All patients were questioned and examined by multidisciplinary medical team, dependent on their complaints. We also registered incidence of comorbidities associated with cellular immune deficiency. The patients with post-COVID syndrome exhibited a decrease of PHA-induced lymphocyte proliferation as compared with control group (significant at p 0.01 in cases of acute respiratory infection, and p 0.05 in patients with pneumonia). Activity of COG-producing cells was similar in all groups, independently on presence of post-COVID syndrome. Classification of patients by presence of cellular immune dysfunction (PHA-induced blast transformation 50%) allowed to detect higher activity of COG-producing cells. This enzyme is known to participate in development of inflammation promoting immune deficiency, thus, probably, manifesting in clinical activation of herpesvirus infection following COVID-19. Activity of COG-synthesizing cells was found to be higher in post-COVID syndrome which evolves after middle-severe and severe forms of new coronavirus infection complicated by pneumonias. Chronic inflammation in post-COVID syndrome associated with high activity of COG-producing cells may promote dysfunction of cell immunity, thus being a cause of evolving syndrome, like as its biomarker. Absence of the immune cell dysfunction markers among other post-COVID features leads to decreased registration of post-COVID patients and misinterpretation of the results obtained.

Slight Pro-Inflammatory Immunomodulation Properties of Dendritic Cells by Gardnerella vaginalis: The "Invisible Man" of Bacterial Vaginosis?

Bacterial vaginosis (BV), the most common genital infection in reproductive-aged women, is associated with increased risk of sexually transmitted infections. Its etiology remains unclear, especially the role of Gardnerella (G.) vaginalis, an anaerobic bacterium characteristic of the BV-alteration of the vaginal ecosystem. In the genital mucosa, dendritic cells (DCs) sense bacteria of the microenvironment via receptors and then orchestrate the immune response by induction of different T cell subtypes. We investigated the interactions between G. vaginalis and human monocyte-derived DCs using a wide range of bacterial concentrations (multiplicity of infection from 0.01 to 100), and the effects of this pathogen on PHA-induced lymphocyte proliferation. As observed by electron microscopy and cytometry, G. vaginalis reduced the internalization ability of DCs by forming extracellular clusters and induced neither DC maturation, nor DC secretion of cytokines, except at the highest dose with a very early DC maturation state. The same profile was observed on lymphocytes with significant increases of proliferation and cytokine secretion only at the highest bacterial concentration. Our findings indicate that G. vaginalis possesses slight immune-stimulating activities against DCs and T cells, reflecting thus a defective inflammatory response and giving rise to the atypical, non- or low-grade, inflammatory clinical disease profile.

Dietary fish oil and flaxseed oil suppress inflammation and immunity in cats

The modulatory activity of dietary n-3 fatty acids on inflammation and immune response in domestic cats is unknown. Mature female cats (n=14/treatment) were fed control, fish oil or flaxseed oil diets with n-6:n-3 fatty acid ratios of 20:1, 5:1 and 5:1, respectively, for 12wk. Immune response was assessed on wk 0, 6 and 12, and skin hypersensitivity response on wk 6 and 12. Fish oil increased (P<0.01) eicosapentaenoic and docosahexaenoic acids in plasma and skin, whereas flaxseed oil increased α-linolenic acid. Fish and flaxseed oils decreased (P<0.01) skin inflammatory response to histamine. Cats fed fish but not flaxseed oil had higher (P<0.05) skin leukotriene LTB5, but not LTB4. Fish and flaxseed oils lowered B, total T and Th subset populations, and leukocyte proliferative response to PWM (P<0.05). In contrast, there was no change in ConA- or PHA-induced lymphocyte proliferation, Tc and MHC II cell populations, DTH response, NK cytotoxicity, IL-2 production, or plasma IgG concentrations. Therefore, fish and flaxseed oil can reduce skin inflammatory responses in cats, however, flaxseed oil appears less immunosuppressive than fish oil.

Effects of Zn and Fe supplementation on the iron status and immunity in female athletes

Athletes are exposed to acute and chronic stress that may lead to suppression of the immune system and increased oxidative species generation. Normal Fe and Zn levels are essential for the development and maintenance of immune functions and antioxidative system for athletes. This study evaluated the effect of Fe and Zn combinative supplementation on the immune function in female athletes with oxidative stress. The experiment group was supplemented with Zn and Fe as Zn glyconate and Fe‐glycerite, respectively, for 2 month. Before and after supplementation, they exercised in treadmill until exertion according to Bruce protocol. The serum concentrations of Fe and Zn were measured by neutron activation analysis method. The hemoglobin levels were not changed in supplemented athletes in contrast to significant decline in placebo athletes. Declines of resting serum Zn and Fe level after 2‐mo. period in athletes were diminished by Zn and Fe supplementation. The reduction of serum Zn levels after exercise was diminished in athletes with Zn and Fe supplements compared to the placebo group. The decline of basophile proportion was significantly diminished by 2‐mo supplementation (p&lt;0.05). However, the increase of PHA‐induced lymphocyte proliferation was lowered by Fe and Zn supplementation in resting state in contrast to increase of ConA‐induced lymphocyte proliferation after exercise.

Generation of CD4+ or CD8+ regulatory T cells upon mesenchymal stem cell-lymphocyte interaction

Mesenchymal stem cells (MSC) have been proposed as a way to treat graft-versus-host disease based of their immunosuppressive effect. We analyzed whether regulatory T cells can be generated in co-cultures of peripheral blood mononuclear cells (PBMC) and MSC. MSC were obtained from the bone marrow of four healthy donors and nine patients with acute leukemia in complete remission following chemotherapy. Short-term (4 days) co-cultures of MSC and autologous or allogeneic PBMC were set up, the lymphocytes harvested and their regulatory activity assessed. Lymphocytes harvested from MSC-PBMC co-cultures strongly inhibit (up to 95%) mixed lymphocyte reaction (MLR), recall to alloantigen, and CD3- or PHA-induced lymphocyte proliferation. These lymphocytes, termed regulatory cells (Regc), were all CD45+CD2+ with variable proportions of CD25+ cells (range 40-75% n=10) and a minor fraction expressed CTLA4 (2-4%, n=10) or glucocorticoid-induced tumor necrosis factcor receptor-related gene (0.5-4% n=10). Both CD4+ and CD8+ Regc purified from MSC-PBMC co-cultures strongly inhibited lymphocyte proliferation at a 1:100 Regc:responder cell ratio. CD4+ Regc expressed high levels of forkhead box P3 (Foxp3) mRNA while CD8+ Regc did not. The effectiveness of Regc, whether CD4+ or CD8+, was 100-fold higher than that of CD4+CD25+high regulatory T cells. Regc were also generated from highly purified CD25- PBMC or CD4+ or CD8+ T cell subsets. Soluble factors, such as interleukin-10, transforming growth factor-b and prostaglandin E2 did not appear to be involved in the generation of Regc or in the Regc-mediated immunosuppressive effect. Furthermore, cyclosporin A did not affect Regc generation or the immunosuppression induced by Regc. These findings indicate that powerful regulatory CD4+ or CD8+ lymphocytes are generated in co-cultures of PBMC with MSC. This strongly suggests that these regulatory cells may amplify the reported MSC-mediated immunosuppressive effect.

Quercetin Reduces Illness Rates But Not Immune Perturbations Following 3 Days Intensive Exercise In Cyclists

PURPOSE: To investigate the effects of quercetin (Q) supplementation on incidence of upper respiratory tract infections (URTI) and exercise-induced changes in stress hormones and immune function. METHODS: Trained male cyclists (N=40) were randomized to Q (N=20) or placebo (P) (N=20) groups and under double blind procedures received 3 wks Q (1000 mg/day) or P prior to, during, and for 2 wks after a 3-d period in which subjects cycled for 3 h/ day at ∼57% Wattsmax. Blood and saliva samples were collected before and after the 3 sessions and assayed for natural killer cell activity (NKCA), PHA-induced lymphocyte proliferation (PHA-LP), granulocyte oxidative burst activity (GOBA), salivary IgA output (sIgA), and plasma cortisol and epinephrine. RESUITS: Pre-to-post-exercise changes inNKCA, PHA-LP, GOBA, sIgA, and plasma cortisol and epinephrine did not differ significantly between Q and P groups. URTI incidence during the 2-week post-exercise period differed significantly between groups (Q= 1/20 vs. P = 9/20, Chi-square = 8.53, P=0.0035). CONCLUSIONS: Q vs. P ingestion did not alter exercise-induced changes in plasma stress hormones and several measures of immune function, but significantly reduced URTI incidence in cyclists during the 2-week period following intensified exercise. Partially Supported by a grant from the Defense Advanced Research Projects Agency (DARPA) and the Army Research Office (ARO), award number W911NF-06-0014.

Immune Changes: 2 h of Continuous vs. Intermittent Cycling

Immune changes following 2 h of intensive cycling with or without rest intervals were measured in trained cyclists (n = 12) who functioned as their own controls during two test sessions that were separated by two weeks. Subjects cycled for 2.0 h at approximately 64 % Watts(max) continuously (C) or with 3-min rest intervals (R) interspersed every 10 min (2.6 h total time), with the order of the sessions randomized. Blood samples were collected 30-min pre-exercise, and immediately and 1-h postexercise, and assayed for blood leukocyte subset counts, plasma IL-6, IL-10, IL-1ra, IL-8, PHA-induced lymphocyte proliferation, and natural killer cell activity (NKCA). Significant time effects were measured for all immune measures, but no significant differences in the pattern of change were found between C and R exercise trials. In conclusion, immune changes induced by 2 h of intense and prolonged exercise paralleled those measured when athletes rested 3 min every 10 min of exercise.

Influence of Carbohydrate on Immune Function Following 2 h Cycling

The influence of carbohydrate compared with placebo ingestion on changes in immune cell counts and functions following 2 h intensive cycling was studied in 12 trained cyclists who functioned as their own controls. The subjects performed two tests 2 weeks apart where they cycled for 2 h at ∼64% Wattsmax while receiving 4 mL·kg−1·15 min−1 carbohydrate (6%) (Cho) or placebo (Pla) beverages. Blood samples were collected 30 min preexercise, and immediately and 1 h postexercise. The samples were assayed for plasma cortisol and epinephrine, blood leukocyte subset counts, PHA-induced lymphocyte proliferation, and natural killer cell activity (NKCA). Compared with Pla ingestion, Cho attenuated exercise-induced changes in plasma cortisol, blood neutrophil, and monocyte counts, but not in total blood lymphocyte, T cell, and NK cell counts, PHA-induced lymphocyte proliferation, and NKCA. Thus despite a strong attenuating influence of carbohydrate ingestion on exercise-induced changes in plasma cortisol and blood neutrophil and monocyte counts, other immune measures related to lymphocyte subset counts, and function were unaffected.

Identification and characterization of a human monoclonal antagonistic antibody AL-57 that preferentially binds the high-affinity form of lymphocyte function-associated antigen-1

LFA-1 (alpha(L)beta(2)) mediates cell-cell and cell-extracellular matrix adhesions essential for immune and inflammatory responses. One critical mechanism regulating LFA-1 activity is the conformational change of the ligand-binding alpha(L) I domain from low-affinity (LA), closed form, to the high-affinity (HA), open form. Most known integrin antagonists bind both forms. Antagonists specific for the HA alpha(L) I domain have not been described. Here, we report the identification and characterization of a human antibody AL-57, which binds to the alpha(L) I domain in a HA but not LA conformation. AL-57 was discovered by selection from a human Fab-displaying library using a locked-open HA I domain as target. AL-57 Fab-phage bound HA I domain-expressing K562 cells (HA cells) in a Mg(2+)-dependent manner. AL-57 IgG also bound HA cells and PBMCs, activated by Mg(2+)/EGTA, PMA, or DTT. The binding profile of AL-57 IgG on PBMCs was the same as that of ICAM-1, the main ligand of LFA-1. In contrast, an anti-alpha(L) murine mAb MHM24 did not distinguish between the HA and LA forms. Moreover, AL-57 IgG blocked ICAM-1 binding to HA cells with a potency greater than MHM24. It also inhibited ICAM-1 binding to PBMCs, blocked adhesion of HA cells to keratinocytes, and inhibited PHA-induced lymphocyte proliferation with potencies comparable with MHM24. These results indicate that specifically targeting the HA I domain is sufficient to inhibit LFA-1-mediated, adhesive functions. AL-57 represents a therapeutic candidate for treatment of inflammatory and autoimmune diseases.

Influence of Carbohydrate/Placebo On Immunity Following 2-h Cycling With or Without Rest Intervals

PURPOSE: The purpose of this project was to study the effect of carbohydrate compared to placebo ingestion on immune changes following 2 hours of intensive cycling with or without rest intervals. METHODS: Trained cyclists (N=12) functioned as their own controls during four test sessions that were separated by 1–2 weeks and randomized to control for an order effect. Subjects cycled for 2.0 h at ∼60% Wattsmax continuously (C) or with 3-min rest intervals (R) interspersed every 10 min (2.6 h total time) while receiving 4 ml kg−1.15 min-1 carbohydrate (6%) (Cho) or placebo (Pla) beverages (thus CCho, CPla, RCho, RPla). Blood samples were collected 30 min pre-exercise, and immediately and 1-h post-exercise. Immune and hormonal measures included determination of leukocyte subset counts, plasma IL-6, IL-10, IL-1ra, IL-8, cortisol, glucose, and insulin, PHA-induced lymphocyte proliferation, and natural killer cell activity (NKCA). Blood leukocyte relative gene expression was measured for four cytokines (IL-6, IL-8, IL-10, IL-1ra) using real-time quantitative RT-PCR. RESULTS: Exercise-induced immune and hormonal changes did not differ between C and R trials. Cho compared to Pla ingestion attenuated exercise-induced changes in blood neutrophil, monocyte, T cell, and NK cell counts, plasma cortisol and insulin, plasma IL-6, IL-10, and IL-1ra, and PHA-induced lymphocyte proliferation, but not NKCA (interaction effect, P=0.134). Significant time effects were measured for leukocyte IL-10 (increase), IL-1ra (increase), and IL-6 (decrease) mRNA content with no significant differences measured when comparing C or R exercise modes or Cho and Pla test conditions. The patterns of change in leukocyte IL-8 mRNA did not differ between Cho and Pla, but increased during C and decreased during R exercise trials (exercise mode × time interaction effect, p < 0.001). CONCLUSIONS: Most measured immune and hormonal changes induced by intense and prolonged exercise were attenuated when cyclists ingested Cho compared to Pla beverages, but were largely unaffected when athletes were allowed to rest 3 min every 10 min of exercise.

Effect of high levels of Cu supplement on growth performance, rumen fermentation, and immune responses in goat kids

An experiment was conducted to determine the effect of high levels of supplemental Cu (as Cu sulfate) on growth performance, rumen fermentation, and immune responses in goats. Fifteen Boer × Spanish goat kids (BW = 21.3 ± 0.7 kg) were fed basal diet containing 14 ppm Cu and were randomly assigned to three treatments: (1) control (no supplemental Cu); (2) 100 mg supplemental Cu/day; (3) 200 mg supplemental Cu/day. Copper sulfate was placed in gelatin capsules and inserted in to the esophagus via a balling gun before the morning feeding. Animals consumed ad libitum twice a day a 70:30 grain:hay diet. Body weight was recorded after 4 h withdrawals from water, for two consecutive days every 2 weeks for 14 weeks. Rumen samples were collected at days 44, 74, and 94 of experiment and blood samples were collected via jugular vein. The cell-mediated immune response was determined via lymphocyte proliferation assay using concanavalin A (ConA) and phytohemagglutinin A (PHA). Humoral immunity was determined on days 50 and 64. Goats were injected with chicken ovalbumin (2 mg/goat) in Freund's incomplete adjuvant. Serum samples were subjected to an ELISA test on days 57, 72, and 98 in order to measure the antibody titer to the chicken ovalbumin. Average daily gain was improved (quadratic, P = 0.05) with 100 mg Cu intake. Protozoa count tended to decrease (linear, P = 0.08) with higher Cu supplementation; however, acetate, propionate or butyrate (mol/100 mol) did not differ ( P > 0.10). An increase (linear, P = 0.03) in leukocyte count was observed, with higher neutrophils (quadratic, P = 0.04) and lower lymphocytes (quadratic, P = 0.01) associated with 100 mg Cu supplementation. ConA-induced lymphocyte proliferation was higher ( P = 0.05) in 100 mg Cu group on day 98; however, PHA-induced lymphocyte proliferation was higher on day 72 (linear, P = 0.01) in the Cu-supplemented groups. Antibody titer to the chicken ovalbumin tended to be higher (linear, P = 0.08) on day 72 and it was higher (linear, P = 0.02) on day 98 in the Cu-supplemented groups. These results indicated that Cu-supplemented at 100 mg/day, improved gain and enhanced the immune response in goat kids.

The effects of conjugated linoleic acid supplementation on immune function in healthy volunteers

To assess the effects of dietary supplementation using two isomeric blends of conjugated linoleic acid (CLA) on immune function in healthy human volunteers. Double-blind, randomised, placebo-controlled intervention trial. A total of 55 healthy volunteers (n=20 males, n=35 females) were randomised into one of three study groups who received 3 g/day of a fatty acid blend containing a 50:50 cis-9, trans-11: trans-10, cis-12 CLA isomer blend (2 g CLA), and 80:20 cis-9, trans-11: trans-10, cis-12 (80:20) CLA isomer blend (1.76 g CLA) or linoleic acid (control, 2 g linoleic acid) for 8 weeks. Supplementation with the 80:20 CLA isomer blend significantly (P< or =0.05) enhanced PHA-induced lymphocyte proliferation. CLA decreased basal interleukin (IL)-2 secretion (P< or =0.01) and increased PHA-induced IL-2 and tumor necrosis factor alpha (TNF(alpha)) production (P< or =0.01). However, these effects were not solely attributable to CLA as similar results were observed with linoleic acid. CLA supplementation had no significant effect on peripheral blood mononuclear cells IL-4 production, or on serum-soluble intercellular adhesion molecule-1 (sICAM-1) or plasma prostaglandin E2 (PGE2) or leukotreine B4 (LTB4) concentrations. This study shows that CLA supplementation had a minimal effect on the markers of human immune function. Furthermore, supplementation with CLA had no immunological benefit compared with linoleic acid.

Immune Response to a 30-Minute Walk

To measure several components of immune changes related to walking 30 min with or without an exercise assist device compared with sitting. Fifteen healthy and nonobese female subjects (37.5 +/- 3.1 yr of age) accustomed to regular walking were recruited and tested for aerobic power (VO(2max) 34.4 +/- 1.4 mL.kg(-1).min(-1)). During three randomly assigned 30-min test sessions, subjects functioned as their own controls and either sat in the laboratory, walked at approximately 60% VO(2max), or walked at the same treadmill speed using the BODY BAT Aerobic Exerciser. This exercise assist device resembles a pair of baseball bats seamlessly joined together and is held with both hands and swung to shoulder height across the body in a natural side to side pendulum motion. Saliva and blood samples were collected pre- and postexercise, and 1 h postexercise, with the data statistically analyzed using a 3 x 3 repeated measures ANOVA. Walking with the exercise assist device increased oxygen consumption 11 +/- 2% and heart rate 8 +/- 2 beats.min(-1). The pattern of increase in blood counts for neutrophils, lymphocytes, monocytes, and natural killer cells, plasma interleukin-6 concentration, and PHA-induced lymphocyte proliferation differed significantly when comparing walking with sitting, but no differences were found between walking with or without the exercise assist device. No significant increases over time or interaction effects were measured for plasma cortisol concentration, salivary IgA output, or plasma interleukin-1 receptor antagonist concentration. The use of an exercise assist device increased oxygen consumption 11% during walking, but did not alter the pattern of change in several components of immunity measured during walking alone in comparison to sitting. Walking caused modest and short-lived changes in immune parameters, most notably for neutrophil and natural killer blood cell counts.

The Immune Response to Walking With and Without an Exercise Assist Device

1754 PURPOSE: To measure immune changes related to walking with or without an exercise assist device compared to sitting. METHODS: Fifteen healthy and nonobese female subjects (37.5 ± 3.1 years of age) accustomed to regular walking were recruited and tested for aerobic power (VO2max 34.4 ± 1.4 ml/kg/min). During three randomly assigned 30 minute test sessions (4:00–4:30 pm), subjects functioned as their own controls and either sat in the laboratory, walked at ∼60% VO2max, or walked at the same treadmill speed using the BODY BAT® Aerobic Exerciser. This exercise assist device resembles a pair of baseball bats seamlessly joined together, and is held with both hands and swung to shoulder height across the body in a natural side to side pendulum motion. Saliva and blood samples were collected pre- and post-exercise, and 1-h post-exercise, with the data statistically analyzed using a 3 × 3 repeated measures ANOVA. RESULTS: Walking with the exercise assist device increased oxygen consumption 11±2% and heart rate 8±2 beats/min. The pattern of increase in blood counts for neutrophils, lymphocytes, monocytes, and natural killer cells, plasma interleukin-6, and PHA-induced lymphocyte proliferation differed significantly when comparing walking with sitting, but no differences were found between walking with or without the exercise assist device. No significant time or interaction effects were measured for plasma cortisol, salivary IgA output, or plasma IL-1ra. CONCLUSIONS: Use of an exercise assist device increased oxygen consumption 11% during walking, but did not alter the pattern of change in immunity measured during walking alone in comparison to sitting.

Human eosinophils regulate T-cell functions through induction of indoleamine 2,3-dioxygenase

Rationale Indoleamine 2,3-dioxygenase (IDO), a rate-limiting enzyme in tryptophan catabolism, is inducible by IFNγ, resulting in kynurenine production, which inhibits proliferation and induce apoptosis of Th1 cells; an important mechanism of inhibition of T-cell function by regulatory dendritic cells. Eosinophils increase during allergen challenge and may interact with T-cells. We hypothesize that the eosinophil-derived IDO plays an immunomodulatory role in the maintenance of Th1-Th2 polarization in allergy. Methods Eosinophils purified from atopic and non-atopic donors were probed for IDO expression by RT-PCR and Western blotting. KYN was measured to determine IDO enzymatic activity. Peripheral blood lymphocyte apoptosis was measured by annexin V following culture with PHA or IFNγ-treated eosinophils. We investigated IDO expression in lung tissue of allergic patients, and in tissues from a mouse model of allergic inflammation, by immunohistochemistry. Results IFNγ-treated eosinophils expressed IDO mRNA and protein, and produced KYN. IL-3, IL-5 and GM-CSF had no effect separately but potentiated IDO induction by IFNγ-treated eosinophils. Eosinophils from atopic but not normal donors, expressed IDO constitutively. Lymphocytes cocultured with IDO-expressing eosinophils underwent apoptosis, which was blocked by the IDO inhibitor, 1-methyl-tryptophan. PHA-induced lymphocyte proliferation was inhibited by eosinophil-derived IDO. We observed extensive infiltration by IDO-expressing eosinophils in lymphoid aggregates from atopic subjects. Additionally, eosinophils were the main IDO-expressing cells found in the lung of OVA-sensitized mouse model of allergic inflammation. Conclusions Eosinophils may regulate T-cell function, in vivo, through IDO induction and thus contribute directly to the maintenance of Th1-Th2 polarization seen in asthma.

Inhibition of lymphocyte proliferation by prenylated flavones: Artelastin as a potent inhibitor

Eight natural prenylated flavones, previously isolated from Artocarpus elasticus, were evaluated for their effect on the mitogenic response of human lymphocytes to PHA. They all exhibited a dose-dependent suppression effect. An interesting relationship was observed between their antiproliferative activity and their chemical structure. Indeed, the most potent flavones possessed a 3,3-dymethylallyl group (prenyl) at C-8, such as artelastin, which exhibited the highest antiproliferative activity. Studies of the mechanism underlying its effect revealed that artelastin had an irreversible inhibitory effect on the PHA-induced lymphocyte proliferation and could affect the course of the ongoing mitogenic response either at the initial induction phase or at the late phase of proliferation. This prenylated flavone was also shown to be a potent inhibitor of both T- and B-lymphocyte mitogen induced proliferation although B-mitogenic response was the more sensitive one. Artelastin did not affect either the basal levels of the early marker of activation CD69 on non-stimulated splenocytes or its expression on ConA- or LPS-stimulated splenocytes. However, it decreased the production of IFN–γ, IL–2, IL–4 and IL–10 in ConA-stimulated splenocytes. Furthermore, artelastin had no effect on apoptosis of splenocytes.

In vitro activity of labdane diterpene from Alomia myriadenia (Asteraceae): immunosuppression via induction of apoptosis in monocytes

A screening program in Brazilian flora was carried out to detect the presence of immunosuppressive compounds by using the in vitro phytohemagglutinin A (PHA)-induced human peripheral blood mononuclear cell (PBMC) proliferation assay. In this screening, we isolated from Alomia myriadenia Schultz-Bip. ex. Baker (Asteraceae), a labdane-type diterpene named myriadenolide. Incubation of human PBMC with this compound reduced significantly the percentage of CD14 + cells, but it has no effect on the relative amount of CD3 +CD4 −CD8 + and CD3 +CD4 +CD8 − T lymphocyte subpopulations. Neither viability nor proliferative competence of T lymphocytes was significantly affected by myriadenolide. The toxic effect on monocytes (CD14 + cells) may explain the inhibitory effect observed on PHA-induced lymphocyte proliferation. The cytotoxic effect of myriadenolide on monocytes was determined by measuring the percentage of hypodiploid nuclei content by propidium iodide staining, electron microscopy and simultaneous detection of CD14 and annexin V binding by flow cytometry. The results showed that myriadenolide induces a dose-dependent apoptosis in monocytes and thus explain the immunosuppressive effect observed.

Ginsenosides from Panax ginseng Differentially Regulate Lymphocyte Proliferation

We have examined the immunosuppressive effects of representative ginsenosides (Rb1, Rb2, Re and Rg1) from Panax ginseng C. A. Meyer on CD4+ and CD8+ lymphocyte proliferation. Ginsenosides differentially modulated lymphocyte proliferation induced by concanavalin A (Con A), lipopolysaccharide (LPS), phytohemaglutinin (PHA) and interleukin-2 (IL-2). Thus, Rb1 and Re significantly enhanced Con A-induced lymphocyte proliferation, whereas Rg1 did not affect the proliferation. Interestingly, however, Rb2 strongly blocked Con A, LPS and PHA-induced lymphocyte proliferation with the IC50 values of 21.8, 29.0 and 24.0 microM, respectively. Moreover, Rb2 inhibited Con A-stimulated IL-2 production with an IC 50 of 13.3 microM. In the IL-2-stimulated CD8+ T cell (CTLL-2) proliferation assay, Re and Rg1 showed strong suppressive effects with IC50 values of 57.5 and 64.7 microM, respectively. In contrast, neither Rb1 nor Rb2 did inhibit CTLL-2 cell proliferation at tested concentrations. These results suggest that ginsenosides from P. ginseng may modulate lymphocyte proliferation in a different manner.

An Exploratory Study into the Effect of Group Psychotherapy on Cardiovascular and Immunoreactivity to Acute Stress in Breast Cancer Patients

Background: Previous studies of cancer patients investigated the effect of psychological treatment on basal endocrine and immune values. Using a randomized experiment, we explored the effect of a 13-week experiential-existential group psychotherapy (EEGP) program on the reactivity to a speech task in breast cancer patients. We explored whether changes in cardiovascular and immune reactivity to a speech task over the 3-month period correlated with changes in psychological distress and emotional expression. Methods: Patients who had been treated for early-stage breast cancer and who were diagnosed as having either positive axillary lymph nodes or distant metastases were randomly assigned to either EEGP or a waiting list control (WLC) condition. We continuously recorded heart rate (HR), diastolic (DBP) and systolic blood pressure (SBP) in response to the speech task before and after treatment. We also measured lymphocyte proliferation to pokeweed (PWM) and phytohemagglutinin (PHA), and natural killer cell activity (NKCA) as well as peripheral blood lymphocyte distributions in blood samples that were drawn before, during and after the speech task. Results: Patients in EEGP had smaller increases in natural killer (NK) cells induced by the speech task after treatment versus task-induced values observed at study entry and greater than pre-/posttreatment changes seen in patients randomized to the WLC. A similar pattern emerged with respect to NKCA over the intervention period, which was independent of the changes in NK cells. There were no differences between patients assigned to EEGP and WLC in HR, DBP and SBP responses as well as in changes in PWM- and PHA-induced lymphocyte proliferation in response to the speech task measured before and after the 3-month intervention period. Individual differences in pre-/posttreatment increases in emotional expression but not in psychological distress were significantly associated with smaller changes in the number and function of NK cells over the 3-month period. Conclusions: These findings may indicate that emotional expression during EEGP may render breast cancer patients more comfortable expressing their emotional responses to the speech challenge, which, in turn, results in smaller stress-induced changes in NK cells and function.

Immunomodulatory Effects of Indomethacin and Prostaglandin E2 on Primary and Secondary Antibody Response in Growing Layer Hens

Effects of prostaglandin E2 (PGE2) and indomethacin, an inhibitor of PGE2 oxygenase, on primary and secondary antibody (Ab) responses to Mycobacterium butyricum protein or keyhole limpet hemocyanin (KLH) were studied in growing layer hens. Immunizations at 35 and 70 d of age were accompanied by immunomodulating treatments with PGE2, indomethacin, or PBS. In addition, we studied effects of various doses of indomethacin and PGE2 on mitogen-induced T-cell proliferation in vitro. Secondary Ab responses to KLH were enhanced by administration of indomethacin at secondary immunization and, to a lesser extent, by PGE2 administration at secondary immunization. Primary Ab responses to M. butyricum tended to decrease by administration of either PGE2 or indomethacin. Secondary Ab responses to M. butyricum were affected by administration of both PGE2 and indomethacin at primary immunization. Prostaglandin E2 increased phytohemagglutinin (PHA)-induced lymphocyte proliferation. Indomethacin decreased Concanavalin A (ConA)- and PHA-induced lymphocyte proliferation. The net effect of indomethacin on the Ab response could not be explained by inhibition of PGE2 oxygenase only. Our data rather suggest an inhibition by indomethacin of other immunosuppressing factors derived from arachidonic acid. We concluded that polyunsaturated fatty acid-derived products might especially affect secondary antibody responsiveness. This finding may depend on inhibition or enhancement of T-cell responsiveness. Consequently, immunomodulation by dietary polyunsaturated fatty acids may have profound effects at secondary rather than at primary exposure to pathogens.