Morita-Baylis-Hillman adduct 2-(3-hydroxy-1-methyl-2-oxoindolin-3-il) acrylonitrile (CISACN) ameliorates the pulmonary allergic inflammation in CARAS model by increasing IFN-γ/IL-4 ratio towards the Th1 immune response

Combined allergic rhinitis and asthma syndrome (CARAS) is an airway-type 2 immune response with a profuse inflammatory process widely affecting the world population. Due to the compromise of quality of life and the lack of specific pharmacotherapy, the search for new molecules becomes relevant. This study aimed to evaluate the effectiveness of the Morita-Bailys-Hillman adduct (CISACN) treatment in the CARAS experimental model. Female BALB/c mice were ovalbumin (OVA) -sensitized and -challenged and treated with CISACN. The treatment decreased the eosinophil migration to the nasal and lung cavities and tissues and the goblet cell hyperplasia/hypertrophy, attenuated airway hyperactivity by reducing the hyperplasia/hypertrophy of the smooth muscle and the extracellular matrix's thickness. Also, the treatment reduced the clinical signs of rhinitis as nasal rubbing and sneezing in a histamine-induced nasal hyperreactivity assay. The immunomodulatory effect of CISACN was by reducing OVA-specific IgE serum level, and IL-33, IL-4, IL-13, and TGF-β production, dependent on IFN-γ increase. Furthermore, the effect of CISACN on lung granulocytes was by decreasing the p-p38MAPK/p65NF-κB signaling pathway. Indeed, CISACN reduced the p38MAPK and p65NF-κB activation. These data demonstrated the anti-inflammatory and immunomodulatory effects of the CISACN with scientific support to become a pharmacological tool to treat airway inflammatory diseases.

Biological Activities of Morita-Baylis-Hillman Adducts (MBHA)

BACKGROUND

The Morita-Baylis-Hillman reaction (MBHR) is considered one of the most powerful and versatile methodologies used for carbon-carbon bond formation. The reaction is defined as the condensation between an electrophilic carbon sp² and the α position of an olefin, carrying an electron-withdrawing group, in the presence of a catalyst. The advantages of the reaction are the high atom economy and mild reaction conditions. Under ideal conditions, this reaction leads to the formation of multifunctional products, called Morita-Baylis-Hillman adducts (MBHA), a class of relevant molecules that exhibit a variety of biological activities.

OBJECTIVE

Considering the importance of these compounds, this review brought together several studies regarding the biological activities of MBHA, to point out the use of these molecules as future therapeutic agents.

METHODS

We searched for scientific articles available in the main databases, published between 1999 and 2022, using the descriptors: Morita-Baylis-Hillman adducts, Morita-Baylis-Hillman reaction, biological activity, and biological potentiality.

RESULTS

Thirty-five articles showed the variety of biological activities of MBHA, including molluscicidal, antitumor, herbicidal, and fungicidal, antileishmanial, antioxidant, antimalarial, anti-tumor inflammatory, vasorelaxant, antichagasic, antimicrobial, and anti-inflammatory activities.

CONCLUSION

Therefore, these compounds are promising candidates to become drugs for the treatment of a variety of diseases, following further studies to understand the effective mechanisms of action of MBHA.

MHTP, a synthetic alkaloid, attenuates combined allergic rhinitis and asthma syndrome through downregulation of the p38/ERK1/2 MAPK signaling pathway in mice

The combined allergic rhinitis and asthma syndrome (CARAS) is a chronic airway inflammation of allergic individuals, with a type 2 immune response. Pharmacotherapy is based on drugs with relevant side effects. Thus, the goal of this study was to evaluate the synthetic alkaloid, MHTP in the experimental model of CARAS. Therefore, BALB/c mice were ovalbumin (OVA) -sensitized and -challenged and treated with MHTP by intranasal or oral routes. Treated animals showed a decrease (p < 0.05) of sneezing, nasal rubbings, and histamine nasal hyperactivity. Besides, MHTP presented binding energy and favorable interaction for adequate anchoring in the histamine H1 receptor. MHTP treatment inhibited the eosinophil migration into the nasal (NALF) and the bronchoalveolar (BALF) fluids. Histological analysis showed that the alkaloid decreased the inflammatory cells in the subepithelial and perivascular regions of nasal tissue and in the peribronchiolar and perivascular regions of lung tissue. The MHTP treatment also reduced the pulmonary hyperactivity by decreasing the smooth muscle layer hypertrophy and the collagen fiber deposition in the extracellular matrix. The immunomodulatory effect of the alkaloid was due to the decrease of cytokines like IL-5 and IL-17A (type 2 and 3), TSLP (epithelial), and the immunoregulatory cytokine, TGF-β. These MHTP effects on granulocytes were dependent on the p38/ERK1/2 MAP kinase signaling pathway axis. Indeed, the synthetic alkaloid reduced the frequency of activation of both kinases independent of the NF-κB (p65) pathway indicating that the molecule shut down the intracellular transduction signals underlie the cytokine gene transcription.

4-Carvomenthenol ameliorates the murine combined allergic rhinitis and asthma syndrome by inhibiting IL-13 and mucus production via p38MAPK/NF-κB signaling pathway axis

The aim of this study was to analyze the 4-carvomenthenol (carvo) oral treatment on the experimental model of the combined allergic rhinitis and asthma syndrome (CARAS). BALB/c mice were OVA-sensitized on day zero and 7th (50 μg/mL OVA in 10 mg/mL Al (OH)3) and OVA-challenged (5 mg/mL, 20 μL/animal) for three weeks. In the last week, the animals were dally challenged with aerosol of OVA and the carvo treatment (12.5, 25 or 50 mg/kg) occurred one hour before each OVA-challenge. Data were analyzed and p < 0.05 was considered significant. Carvo (12.5-50 mg/kg) decreased significantly the eosinophil migration into the nasal (NALF) and bronchoalveolar (BALF) cavities as well as on the nasal and lung tissues of sick animals. The treatment also decreased mucus production on both tissue sections stained with PAS (periodic acid-Schiff satin). In addition, the histological analyzes demonstrated that sick mice presented hyperplasia and hypertrophy of the lung smooth muscle layer followed by increasing of extracellular matrix and carvo (50 mg/kg) inhibited these asthmatic parameters. We analyzed the allergic rhinitis signals as nasal frictions and sneezing and observed that carvo decreased these two signals as well as serum OVA-specific IgE titer, type 2 cytokine synthesis, mainly IL-13, with increasing of IL-10 production. Decreasing of IL-13 production corroborated with decreasing of mucus production and these effects were dependent on p38MAPK/NF-κB(p65) signaling pathway inhibition. Therefore, these data demonstrated that a monoterpene of essential oils presents anti-allergic property on an experimental model of CARAS suggesting a new drug prototype to treat this allergic syndrome.

Combined allergic rhinitis and asthma syndrome (CARAS)

Combined allergic rhinitis and asthma syndrome (CARAS) is a concept of "one airway - one disease" or "unified airway disease ". The upper and lower airway inflammation characterizes allergic rhinitis and asthma, respectively and both diseases have shown an intimate connection in their genesis, coexistence and similarities as triggered by the same etiological agents; the same inflammatory cell profile and share therapeutic treatment. This review highlights the concept of CARAS by its phenotype, endotype and biomarker classification. Indeed, rhinitis is divided into four major phenotypes: allergic rhinitis; infectious rhinitis; non-infective/non-allergic rhinitis and mixed rhinitis. On the other hand, asthma has no common consensus yet; however, the most accepted classification is based on the stage of life (early- or late- onset asthma) in which the clinical symptoms are presented. Experimental researches where animals develop a syndrome similar to CARAS have been contributed to better understand the pathogenesis of the syndrome. Therefore, the aim of this review is to clarify current terms related to CARAS as definition, phenotypes, endotypes/biomarkers, physiopathology and treatments.

MHTP, 2-Methoxy-4-(7-methoxy-1,2,3,4-tetrahydroisoquinolin-1-yl) phenol, a Synthetic Alkaloid, Induces IFN-γ Production in Murine Model of Ovalbumin-Induced Pulmonary Allergic Inflammation

MHTP [2-methoxy-4-(7-methoxy-1,2,3,4-tetrahydroisoquinolin-1-yl) phenol], a synthetic isoquinolinic alkaloid, presented anti-inflammatory activity in several experimental models of acute inflammation as lipopolysaccharide (LPS)-induced acute lung injury and phlogistic agent-induced edema and presented low preclinical toxicity. The aim of this study was to determine the MHTP effect on ovalbumin (OVA)-induced pulmonary allergic inflammation. In other to realize this study, female BALFB/c mice were sensitized and challenged with OVA (OVA group) and treated with MHTP (MHTP group) by nasal instillation. Inflammatory, allergic, and immunomodulatory parameters such as migration of inflammatory cells to the lung tissue, pulmonary histological analysis, serum level of IgE-allergen specific, cytokine secretion, and lung T cell population characterization were analyzed and the data were considered statistically significant with p < 0.05. OVA-sensitized and OVA-challenged and MHTP (5.0 mg/kg)-treated mice presented reduction on total leukocyte migration into the bronchoalveolar lavage (BALF) dependent of lymphocyte and eosinophil migration (p < 0.001 and p < 0.01) as compared with the OVA group. Flow cytometric analysis showed that MHTP treatment decreased the percentage of granulocytes (p < 0.001) into the BALF and lung tissue histological analyzes demonstrated that the MHTP treatment decreased leukocyte migration and mucus production. In addition, treatment with MHTP decreased the number of CD3⁺CD4⁺ T cells independently of CD8⁺ T cell reduction into the BALF. The treatment also reduced significantly (p < 0.05) the serum level of IgE-OVA specific followed by reduction of IL-4, IL-13, and IL-17 production. Surprisingly, the MHTP treatment increased significantly (p < 0.05) the IFN-γ production in the BALF of these animals. Therefore, the results presented here showed that MHTP treatment, by nasal instillation, in a mouse model of OVA-induced pulmonary allergy has anti-allergic and immunomodulatory effects dependent on a Th1-skewed cytokine production that ameliorate the pulmonary allergic inflammation.

Milonine, an Alkaloid of Cissampelos sympodialis Eichl. (Menispermaceae) Inhibits Histamine Release of Activated Mast Cells

Milonine is an alkaloid of Cissampelos sympodialis Eichl. (Menispermaceae), a plant used in the northeast of Brazil to treat allergies such as asthma, rhinitis, and other conditions. Previously, several alkaloids were isolated from its roots and leaves with pharmacological properties in asthma and acute inflammation models. Therefore, the aim of this study was to evaluate the milonine effect on mast cells degranulation in vivo and in vitro. Swiss mice (n = 8) were used in models of paw edema induced by carrageenan, compound 48/80, or histamine. One hour before challenge, the animals were treated with milonine (at different doses) or standard drugs and, at different time points, the edema formation was measured. In addition, other different methods, such as anaphylactic shock reaction and scratching behavior models both induced by compound 48/80, a mast cell degranulator, were used to assess milonine effect histamine release in vivo. Moreover, milonine effect on mast cell degranulation in vitro was also carried out. Firstly, it was observed that milonine significantly decreased the carrageenan edema formation only at the beginning of the reaction (i.e., up to 2 h after challenge). Furthermore, this alkaloid decreased the edema induced by compound 48/80, maintained the paw tissue integrity, without modulating histamine-induced paw edema. In anaphylactic shock reaction, milonine increased the time of animal survival when compared with compound 48/80 group. Milonine also significantly decreased the scratching behavior induced by compound 48/80 with decreasing of mast cell degranulation in vitro. Therefore, these data indicated that milonine presents anti-allergic properties by decreasing mast cell degranulation rather than acting on histamine effect.

Ouabain attenuates ovalbumin-induced airway inflammation

PURPOSE

Ouabain, an Na⁺/K⁺-ATPase inhibitor hormone, presents immunomodulatory actions, including anti-inflammatory effect on acute inflammation models.

METHODS

In the present study, the effect of ouabain in a model of allergic airway inflammation induced by ovalbumin (OVA) was assessed.

RESULTS

Initially, it was observed that ouabain treatment inhibited cellular migration induced by OVA on bronchoalveolar lavage fluid (BALF), mostly granulocytes, without modulating macrophage migration. In addition, it was observed, by flow cytometry, that ouabain reduces CD3^high lymphocytes cells on BALF. Furthermore, treatment with ouabain decreased IL-4 and IL-13 levels on BALF. Ouabain also promoted pulmonary histological alterations, including decreased cell migration into peribronchiolar and perivascular areas, and reduced mucus production in bronchioles regions observed through hematoxylin-eosin (HE) and by periodic acid-Schiff stain, respectively. Allergic airway inflammation is characterized by high OVA-specific IgE serum titer. This parameter was also reduced by the treatment with ouabain.

CONCLUSIONS

Therefore, our data demonstrate that ouabain negatively modulates allergic airway inflammation induced by OVA.

Gamma-Terpinene Modulation of LPS-Stimulated Macrophages is Dependent on the PGE2/IL-10 Axis

Gamma-terpinene is a monoterpene present in the essential oils of several plants, including those from the Eucalyptus genus. This molecule was recently described as anti-inflammatory and microbiocidal, but little is known about the mechanisms behind its effects. The aim of the present study was to investigate the effect of gamma-terpinene on the lipopolysaccharide-induced production of cytokines by murine peritoneal macrophages. Gamma-terpinene treatment was found to reduce the production of proinflammatory cytokines, such as interleukin-1β and interleukin-6, and enhance that of the anti-inflammatory cytokine interleukin-10. This was accompanied by increased levels of the enzyme cycloxygenase-2 and its product, the lipid mediator prostaglandin E₂. Inhibition of cycloxygenase-2 with nimesulide abolished the potentiating effect of gamma-terpinene on interleukin-10 production. Moreover, nimesulide treatment also abrogated the inhibitory effect of gamma-terpinene on interleukin-1β and interleukin-6. Furthermore, in macrophages from mice deficient in the interleukin-10 gene, gamma-terpinene failed to inhibit interleukin-1β and interleukin-6 production. These results suggest that this monoterpene promotes the prostaglandin E₂/interleukin-10 axis, which inhibits the production of these proinflammatory cytokines.

Anti-asthmatic and anxiolytic effects of Herissantia tiubae, a Brazilian medicinal plant

Herissantia tiubae (HtE) is a Brazilian plant used in folk medicine to treat inflammatory diseases. Our aim was to determine whether the HtE has anti-inflammatory and anxiolytic effects in a murine model of asthma. Ovalbumin (OVA)-sensitized BALB/c mice were treated with HtE (50, 100, or 200 mg/kg) or dexamethasone before each OVA challenge. After the last challenge, animals were subjected to anxiety tests and respiratory measurements. Following euthanasia, we quantified immune cells in the bronchoalveolar lavage (BAL), serum IgE titer and cytokine levels, cellular infiltration and mucus content in the lung tissues, and cellular composition of the mediastinal lymph nodes. OVA challenge in sensitized animals caused: (1) reduction of mean respiratory and dominant respiratory rate (from 398 ± 12 to 286 ± 20 cicles per minute (cpm) and from 320 ± 14 to 162 ± 15 cpm, respectively); (2) increase in behavioral markers of anxiety tests; (3) substantial pro-inflammatory effects, including rise in OVA-specific IgE titer (from 0 to 1:2048) and these inflammatory effect diminished the titer to 1:512 after HtE treatment; rise in plasma IL-13 (from 13 ng/mL in saline to 227 ng/mL in OVA and HtE treatment restored to 1.29 ng/mL; rise in total BAL cell count (from 0.742 cells/mL in saline to 11.77 cells/mL in OVA), with prominent eosinophilia. H. tiubae extract affected respiratory parameters similarly to aminophylline, behavioral changes comparable to diazepam, and inflammation being as efficient as dexamethasone. H. tiubae extract (HtE) possesses both anti-inflammatory and anxiolytic properties in the murine model of asthma.

Gamma-Terpinene Modulates Acute Inflammatory Response in Mice

The monoterpene gamma-terpinene is a natural compound present in essential oils of a wide variety of plants, including the Eucalyptus genus, which has been reported to possess anti-inflammatory activity. The goal of this study was to evaluate the effect of gamma-terpinene on several in vivo experimental models of acute inflammation. Swiss mice were pretreated with gamma-terpinene and subjected to protocols of paw edema with different phlogistic agents such as carrageenan, prostaglandin-E2, histamine, or bradykinin. The microvascular permeability was measured by intraperitoneal injection of acetic acid and measuring the amount of protein extravasation. Carrageenan-induced peritonitis was used to analyze the effect of gamma-terpinene on inflammatory cell migration and cytokine production. We also developed an acute lung injury protocol to define the anti-inflammatory effect of gamma-terpinene. Mice pretreated with gamma-terpinene displayed reduced paw edema induced by carrageenan from 1-24 h after challenge. A similar reduction was observed when gamma-terpinene was administered after stimulation with PGE2, bradykinin, and histamine. Treatment with gamma-terpinene also inhibited fluid extravasation in the acetic acid model of microvascular permeability. In a carrageenan-induced peritonitis model, gamma-terpinene treatment reduced neutrophil migration as well as the production of interleukin-1β and tumor necrosis factor-α when compared to nontreated animals, and in the acute lung injury protocol, gamma-terpinene diminished the neutrophil migration into lung tissue independently of the total protein extravasation in the lung. These data demonstrate that, in different models of inflammation, treatment with gamma-terpinene alleviated inflammatory parameters such as edema and pro-inflammatory cytokine production, as well as cell migration into the inflamed site, and that this monoterpene has anti-inflammatory properties.

Synthesis, toxicity study and anti-inflammatory effect of MHTP, a new tetrahydroisoquinoline alkaloid

The alkaloid 2-methoxy-4-(7-methoxy-1,2,3,4-tetrahydroisoquinolin-1-yl)phenol (MHTP) was synthesized to prospect new compounds with therapeutic properties. Thus, the goal of this study was to evaluate the MHTP anti-inflammatory effect by in vivo and in vitro assays. The MHTP toxicity was analyzed. We found that MHTP pre-treatment (2.5-10 mg/kg) showed antiedematogenic effect (p < 0.05) in carrageenan-induced paw edema by inhibiting the PGE2 action independently of mast cell degranulation or histamine activity. MHTP also diminished (p < 0.01) total leukocyte migration in 41.5% into peritoneal cavity during carrageenan-induced peritonitis, reducing polymorphonuclear cells (PMNs) (59.6%) and proteins levels (29.4%). MHTP in an experimental model of acute lung injury inhibited (p < 0.001) total inflammatory cell migration into the lungs and PMNs in 58% and 67.5%, respectively. Additionally, MHTP did not present cytotoxicity at concentrations of 10, 25 or 50 μM but decreased (p < 0.001) the NO production in 24%, 47% and 39%, respectively. The alkaloid also reduced (p < 0.001, in lipopolysaccharide (LPS)-stimulated macrophages (1 μg/mL), IL-1β, IL-6 and IL-10 levels in 35.7%, 31.0% and 33.4%, respectively. The results obtained in this study allow us to conclude that the inedited synthetic alkaloid, MHTP has anti-inflammatory effect by inhibiting PGE2 function as well as inhibiting inflammatory cell migration to the inflamed site and attenuated the acute lung injury disease by inhibiting the migration of neutrophil to the lung. However, further studies will be carried out to demonstrate the mechanisms of action of the molecule and explore its potential as a future drug to treat inflammatory processes.

Curine, an alkaloid isolated from Chondrodendron platyphyllum inhibits prostaglandin E2 in experimental models of inflammation and pain

Curine is a bisbenzylisoquinoline alkaloid that is isolated from Chondrodendron platyphyllum, a plant that is used to treat malaria, inflammation, and pain. Recent reports have demonstrated the antiallergic effects of curine at nontoxic doses. However, its anti-inflammatory and analgesic properties remain to be elucidated. This study investigated the anti-inflammatory and analgesic effects of curine in mice. We analyzed the effects of an oral treatment with curine in the formation of paw edema, vascular permeability, abdominal contortion, licking behavior, and hyperalgesia using different inflammatory stimuli. Curine significantly inhibited the formation of paw edema by decreasing vascular permeability, inhibited the acetic acid-induced writhing response, inhibited the licking behavior during inflammation but not during the neurogenic phase of the formalin test, and inhibited carrageenan-induced hyperalgesia. Finally, curine inhibited prostaglandin E2 production in vitro without affecting cyclooxygenase-2 expression. The effects of curine treatment were similar to the effects of indomethacin, but were different from the effects of morphine treatment, suggesting that the analgesic effects of curine do not result from the direct inhibition of neuronal activation but instead depend on anti-inflammatory mechanisms that, at least in part, result from the inhibition of prostaglandin E2 production. In conclusion, curine presents anti-inflammatory and analgesic effects at nontoxic doses and has the potential for use in anti-inflammatory drug development.

Managing murine food allergy with Cissampelos sympodialis Eichl (Menispermaceae) and its alkaloids

Food allergy is a severe human disease with imminent risk of life. Cissampelos sympodialis (Menispermaceae) is a native Brazilian plant used in Brazilian folk medicine for the treatment of respiratory allergies. In this study the experimental model of food allergy induced by ovalbumin (OVA) was used to determine whether the alcoholic extract of the plant (AFL) and its alkaloids match a therapeutic approach for this disease. Animal weight, diarrhea, OVA-specific IgE levels, inflammatory cell and cytokine profiles, mucus production and proportion of T cells on the mesenteric lymph node (MLN) were evaluated. Warifteine (W) or methyl-warifteine (MW) alkaloids slightly improve diarrhea score independently of AFL and all treatments decreased the OVA-specific IgE levels. Stimulated mesenteric lymph node (MLN) cells in the presence of the alkaloids diminished the IL-12p70 levels independently of IFN-γ or IL-13 secretion. The alkaloids increased the number of Treg cells on MLN and reduced the number of eosinophils and mast cells as well as mucus production in the gut. Therefore, the alkaloids modulate the immune response in food allergy by increasing regulatory T cells in MLN independently of Th1 or Th2 profiles.

Salivary cortisol and frailty syndrome in elderly residents of long-stay institutions: a cross-sectional study

Analyze the relationship between frailty and cortisol in elderly residents of long-stay institutions. A cross-sectional study was conducted in the city of João Pessoa-PB-Brazil, on a sample of residents of long-stay institutions. Data were collected on frailty phenotype (weight loss, fatigue, slowness, weakness and low physical activity) and salivary cortisol (first measurement between 6 and 7a.m.; second measurement between 11 and 12a.m.; third measurement between 4 and 5p.m.). Statistical analysis applied Pearson's correlation test, Chi-square test, ANOVA and linear regression. The sample was composed of 69 elderly subjects, 37.7% men and 62.3% women, with a mean age of 77.5 (±7.8) years. The percentage of frail elderly was 45.8%. Frail aged subjects achieved higher cortisol values on the third measurement (p=0.04) and frailty load was significantly associated to the first measurement (r=0.25, p=0.04). Simple linear regression analysis showed a rate of determination (R(2)=0.05) between frailty load and the first cortisol measurement. Greater cortisol values in the morning and before bed among frail aged individuals suggest a positive correlation may exist between cortisol levels and frailty in elderly residents of long-stay institutions.

Anti-allergic effect of bee pollen phenolic extract and myricetin in ovalbumin-sensitized mice

ETHNOPHARMACOLOGICAL RELEVANCE

The bee pollen is used in folk medicine to alleviate allergic reactions. The bee pollen phenolic extract (BPPE) consists in phenolic compounds (flavonoids) from plants picked by Apis mellifera bee.

AIM OF THIS STUDY

Here we evaluated the anti-allergic property of the BPPE and the flavonoid myricetin (MYR) in murine model of ovalbumin (OVA)-induced allergy.

MATERIALS AND METHODS

The study focused on the BPPE or myricetin treatment of OVA-sensitized BALB/c mice and their effects on the IgE and IgG1 production, pulmonary cell migration, eosinophil peroxidase (EPO) activity and anaphylactic shock reaction.

RESULTS

The BPPE treatment (200mg/kg) showed inhibition of the paw edema, IgE and IgG(1) OVA-specific production, leukocyte migration to the bronchoalveolar lavage (BAL) and EPO activity in lungs. In addition, BPPE treatment showed partial protection on the anaphylactic shock reaction induced by OVA. Treatment with myricetin (5 mg/kg) also inhibited pulmonary cell migration and IgE and IgG(1) OVA-specific production.

CONCLUSIONS

These results support the hypothesis the myricetin is one of the flavonoids of BPPE responsible for the anti-allergic effect and a potential tool to treat allergies.

Cissampelos sympodialis Eichl. (Menispermaceae): oral treatment decreases IgE levels and induces a Th1-skewed cytokine production in ovalbumin-sensitized mice

The murine model of ovalbumin (OVA)-induced allergy was used to evaluate the effectiveness of oral treatment with the leaf extract of Cissampelos sympodialis Eichl. (Menispermaceae) (CS) in the modulation of immunoglobulin E (IgE) production and T cell activation. CS treatment with doses ranging from 200 to 600 mg/Kg/day for 15 days before and during OVA-sensitization promoted reduction in total and OVA-specific serum IgE. CS at 400 or 600 mg/Kg/day also reduced paw edema induced by local OVA challenge. Daily intake of up to 600 mg/Kg of oral CS by BALB/c mice did not reduce weight gain, which is indicative of a lack of systemic toxicity. To assess the effect of CS treatment on T cell proliferative response to stimuli in vitro, the mitogenic response of spleen cells of treated and control animals were evaluated. Cells from CS-treated animals showed an elevated background proliferative response to concanavalin-A (Con-A) when compared to those from control animals. Oral intake of CS increased the in vitro production of IFN-gamma and IL-10 by Con-A stimulated cells. Mice treated with 200 mg/Kg/day CS showed increasing levels of IFN-gamma. These results show that oral treatment with Cissampelos sympodialis extract has an immunomodulatory effect, reducing allergy-associated responses possibly by a preferential activation of Th1-type cytokines.

Modulation of B lymphocyte function by an aqueous fraction of the ethanol extract of Cissampelos sympodialis Eichl (Menispermaceae)

Cissampelos sympodialis Eichl species are used in folk medicine for the treatment of asthma, arthritis and rheumatism. In the present study, we investigated the immunomodulatory effect of an aqueous fraction of a 70% (v/v) ethanol extract of C. sympodialis leaves on B lymphocyte function. The hydroalcoholic extract inhibited the in vitro proliferative response of resting B cells induced by LPS (IC50 = 17.2 g/ml), anti-delta-dextran (IC50 = 13.9 g/ml) and anti-IgM (IC50 = 24.3 g/ml) but did not affect the anti-MHC class II antibody-stimulated proliferative response of B cell blasts obtained by stimulation with IL-4 and anti-IgM. Incubation with the hydroalcoholic extract used at 50 g/ml induced a 700% increase in intracellular cAMP levels. IgM secretion by resting B cells (obtained from normal mice) and polyclonally activated B cells (obtained from Trypanosoma cruzi-infected animals) was inhibited by the hydroalcoholic extract. The latter were more sensitive to the hydroalcoholic extract since 6.5 g/ml induced a 20% inhibition in the response of cells from normal mice while it inhibited the response of B cells from infected animals by 75%. The present data indicate that the alcoholic extract of C. sympodialis inhibited B cell function through an increase in intracellular cAMP levels. The finding that the hydroalcoholic extract inhibited immunoglobulin secretion suggests a therapeutic use for the extract from C. sympodialis in conditions associated with unregulated B cell function and enhanced immunoglobulin secretion. Finally, the inhibitory effect of the hydroalcoholic extract on B cells may indicate an anti-inflammatory effect of this extract.

Cissampelos sympodialis Eichl (Menispermaceae) leaf extract induces interleukin-10-dependent inhibition of Trypanosoma cruzi killing by macrophages

The aqueous fraction of the ethanolic extract (AFL) of Cissampelos sympodialis Eichl (Menispermaceae), popularly known as milona, has been shown to have both immunosuppressive and anti-inflammatory effects. In the present study we investigated the modulation of macrophage antimicrobicidal activity by in vitro treatment with the extract from C. sympodialis. Normal and thioglycolate-elicited mouse peritoneal macrophages were infected in vitro with the protozoan Trypanosoma cruzi DM28c clone. We observed that the AFL (used at doses ranging from 13 to 100 microg/ml) increased T. cruzi growth and induced a 75% reduction in nitric oxide production. This inhibition could be mediated by the stimulation of macrophage interleukin-10 (IL-10) secretion since the in vitro treatment with the AFL stimulated IL-10 production by T. cruzi-infected macrophages. These results suggest that the anti-inflammatory effect of the AFL from C. sympodialis could be, at least in part, mediated by the inhibition of macrophage functions and that the inhibition of macrophage microbicidal activity induced by the C. sympodialis extract may be mediated by the decrease in macrophage function mediated by interleukin-10 production.

Studies on the anti-inflammatory and analgesic activity of Curatella americana L

Curatella americana L. (Dilleneaceae) popularly known as 'cajueiro-bravo' and 'sambaiba' is used in Brazilian folk medicine for the treatment of inflammation and ulcer. The anti-inflammatory and analgesic tests were conducted with the hydroalcoholic extract (HAE) of the bark of the plant. The HAE inhibited mouse ear oedema induced by o-tetradecanoyl phorbol acetate (TPA) and by capsaicin. While the ID50 values obtained for the HAE against these two irritants were 40.8 +/- 1.7 and 30 +/- 1.2 mg/kg i.p. (mean +/- S.E.M., n = 6), respectively, the corresponding value for carrageenan induced paw oedema (3 h) was 21.8 +/- 2.1 mg/kg, i.p., n = 6. In the established adjuvant-induced arthritis model, the HAE significantly inhibited the oedema in daily doses of 50 mg/kg, i.p. (n = 10). The HAE also inhibited acetic acid-induced writhing (ID50 23.2 +/- 0.8 mg/kg, i.p., n = 6) and the formalin-induced late phase paw licking response (ID50 11.9 +/- 1.2 mg/kg, i.p., n = 10) in the mice. However, the HAE was inactive in the formalin-induced initial paw licking response in mice or heat induced tail flick response in rats. The HAE has shown both anti-inflammatory and peripheral analgesic activities when administrated in the mouse by the intraperitoneal route in doses which are at least 12 times lower than its LD50 dose of 647 mg/kg, i.p.

Cissampelos sympodialis Eichl. leaf extract increases the production of IL-10 by concanavalin-A-treated BALB/c spleen cells

The effect of the aqueous fraction of the ethanol extract of Cissampelos sympodialis Eichl. (Menispermaceae) leaves (AFL) on Concanavalin-A (Con-A)-activated spleen cell proliferation and cytokine (IL-2, IL-4, IL-10 and IFN-gamma) secretion were analyzed. BALB/c spleen cells were treated, in vitro, with different concentrations, ranging from 6.25 to 400 microg/ml of AFL either in the presence or the absence of 5 microg/ml of the mitogen Con-A. It was observed that concentrations of the AFL higher then 50 microg/ml were toxic to the cells and concentrations ranging from 6.25 to 50 microg/ml decreased the lymphocyte proliferative response in the presence of the mitogen. This inhibition of mitogen induced proliferation was not reverted by the addition of exogenous recombinant IL-2. The AFL did not significantly inhibit IL-2 secretion. In the presence of AFL there was a reduction in the levels of secreted IFN-gamma while the production of both IL-10 and IL-4 were increased. AFL did not induce the production of any of the cytokines analyzed, in the absence of Con-A. It is suggested that increased IL-10 production down regulates IFN-gamma secretion and T cell proliferative responses.

Analysis and partial epitope mapping of human T cell responses to Trypanosoma cruzi cysteinyl proteinase

Human infection with Trypanosoma cruzi (Chagas' disease) is usually accompanied by humoral and cellular immune responses to GP57/51, a major antigen that was recently identified as a prominent cysteinyl proteinase (cruzipain). The PBMC responses of 11 chronic chagasic patients and the properties of anti-cruzipain T cell lines are reported herein. GP57/51, isolated from Y strain epimastigotes (n-cruzipain) or the recombinant protein expressed in E. coli (r-cruzipain), elicited proliferative responses of variable intensity from the patient's PBMC. T cell lines were then generated using each of these antigens. These lines, which always carried the CD4+ phenotype, were reciprocally stimulated by n-cruzipain or r-cruzipain, the responses to the former being usually stronger. The analysis of cytokine production suggested that Th1-like subsets dominate the patient's responses: IFN-gamma was consistently induced on stimulation with either n-cruzipain or r-cruzipain. In contrast, IL-4 was present in very small concentrations or was undetectable. We then sought to define T cell epitopes of cruzipain using synthetic peptides spanning portions of the central (catalytic) domain and COOH-terminal extension. From a panel of 11 peptides, only one 33 mer peptide (P214) elicited a strong proliferative response on anti-cruzipain T cell lines, the intensity being comparable to that induced by r-cruzipain. Conversely, T cell lines started with P214 were responsive to either n-cruzipain or r-cruzipain, the proliferative responses again being accompanied by IFN-gamma production, but not IL-4. Interestingly, P214 is located in a conserved region of the catalytic domain of cruzipain, hence may propitiate opportunities for cross-recognition of other members of the papain superfamily. Fine epitope mapping should reveal whether structurally similar regions of host thiol-cathepsins can be potential targets for cross-reactive T cell responses during chronic human infection.

Analysis and partial epitope mapping of human T cell responses to Trypanosoma cruzi cysteinyl proteinase

Human infection with Trypanosoma cruzi (Chagas' disease) is usually accompanied by humoral and cellular immune responses to GP57/51, a major antigen that was recently identified as a prominent cysteinyl proteinase (cruzipain). The PBMC responses of 11 chronic chagasic patients and the properties of anti-cruzipain T cell lines are reported herein. GP57/51, isolated from Y strain epimastigotes (n-cruzipain) or the recombinant protein expressed in E. coli (r-cruzipain), elicited proliferative responses of variable intensity from the patient's PBMC. T cell lines were then generated using each of these antigens. These lines, which always carried the CD4+ phenotype, were reciprocally stimulated by n-cruzipain or r-cruzipain, the responses to the former being usually stronger. The analysis of cytokine production suggested that Th1-like subsets dominate the patient's responses: IFN-gamma was consistently induced on stimulation with either n-cruzipain or r-cruzipain. In contrast, IL-4 was present in very small concentrations or was undetectable. We then sought to define T cell epitopes of cruzipain using synthetic peptides spanning portions of the central (catalytic) domain and COOH-terminal extension. From a panel of 11 peptides, only one 33 mer peptide (P214) elicited a strong proliferative response on anti-cruzipain T cell lines, the intensity being comparable to that induced by r-cruzipain. Conversely, T cell lines started with P214 were responsive to either n-cruzipain or r-cruzipain, the proliferative responses again being accompanied by IFN-gamma production, but not IL-4. Interestingly, P214 is located in a conserved region of the catalytic domain of cruzipain, hence may propitiate opportunities for cross-recognition of other members of the papain superfamily. Fine epitope mapping should reveal whether structurally similar regions of host thiol-cathepsins can be potential targets for cross-reactive T cell responses during chronic human infection.

Rapid competitive enzyme-linked immunosorbent assay using a monoclonal antibody reacting with a 15-kilodalton tegumental antigen of Schistosoma mansoni for serodiagnosis of schistosomiasis

A competitive enzyme-linked immunosorbent assay (CELISA) for antibody detection was developed by using a monoclonal antibody which reacts with a 15-kDa tegumental antigen of the adult worm of Schistosoma mansoni. This monoclonal antibody was not able to react with antigens of Schistosoma japonicum or Schistosoma haematobium in enzyme-linked immunoelectrotransfer blot (EITB) and indirect immunofluorescence tests. The assay was performed in a period of 1 h using an adult worm crude extract antigen. To evaluate the CELISA, a total of 73 serum samples was analyzed: 35 were from S. mansoni-infected patients, 23 were from individuals with parasitic infections other than schistosomiasis, and 14 were from healthy individuals. All serum samples from healthy individuals and from patients infected with other parasites were negative, as were two (6%) samples from patients infected with S. mansoni. EITB analysis showed that 32 of 33 CELISA-positive samples were positive in the EITB but with different patterns of reactivity. A 15-kDa protein reacted with 60% of serum samples, and a 60-kDa protein showed the highest level of reactivity (85%). The two samples from patients infected with S. mansoni that were negative in the CELISA reacted with 70-, 60-, 50-, 47-, and 38-kDa proteins. One sample, positive in CELISA, did not react with proteins of the antigenic extract.

Interleukin 10 production correlates with pathology in human Leishmania donovani infections

We have found that an important Th2 cytokine, IL-10, is produced by tissues from patients acutely infected with Leishmania donovani. In all individuals tested, IL-10 mRNA production was increased in lymph nodes taken during acute disease over that observed in postacute samples. In contrast, both pre- and posttreatment lymph nodes had readily detected mRNA for IFN-gamma and IL-2. A down-regulating effect of IL-10 on leishmania-induced proliferative responses was demonstrated when Hu rIL-10 was added to cultures of PBMC from clinically cured individuals. PBMC from individuals with acute visceral leishmaniasis responded to stimulation with leishmania lysate by producing IL-10 mRNA. Simultaneously cultured PBMC collected from the same patients after successful chemotherapy produced no detectable IL-10 mRNA after leishmania antigen stimulation. Neutralizing anti-IL-10 mAb added to PBMC from patients with acute visceral leishmaniasis markedly increased the proliferative response to leishmania lysate. Finally, we observed mRNA for IL-10 and IFN-gamma concurrently in a lesion from a patient with post-kala-azar dermal leishmaniasis (PKDL). These results indicate the production of IL-10 during L. donovani infection, and suggest a role for this cytokine in the regulation of immune responsiveness during visceral leishmaniasis.

Characterization of responses of normal human T cells to Trypanosoma cruzi antigens

The stimulation of normal human PBMC by Trypanosoma cruzi Ag was analyzed. PBMC showed significant in vitro proliferation in response to parasite lysate (Tct), with stimulation indices ranging from 10 to 400, peaking at 6 to 7 days. The cells stimulated with Tct produced significant levels of IL-2. To determine which cells proliferated in response to Tct, PBMC were separated into T- and B-enriched cell populations. Purified T cells, but not B cells, proliferated strongly to Tct. The T cell response required APC and was processing dependent. T cell lines generated against Tct proliferated in response to parasite lysate only in the presence of autologous APC and produced IL-2, IL-6, and IFN-gamma but not IL-4 in response to PMA plus ionomycin. Although there were a significant number of CD45Ra+ cells, the majority of the cells in these T cell lines were CD45Ro+. The V beta usage of Tct-responding T cells was heterogeneous, with most V beta genes represented among the responding cells. An immunodominant repeat Ag (TcD) and a ribosomal phosphoprotein (P0) of T. cruzi elicited strong proliferative responses in all subjects tested. These data indicate the presence of T cell-stimulatory Ag in Tct, characterized by nonpreferential usage of the V beta gene families. The strong stimulation of normal human PBMC by Tct may contribute to immunologic alterations seen in T. cruzi infection.

Characterization of responses of normal human T cells to Trypanosoma cruzi antigens

The stimulation of normal human PBMC by Trypanosoma cruzi Ag was analyzed. PBMC showed significant in vitro proliferation in response to parasite lysate (Tct), with stimulation indices ranging from 10 to 400, peaking at 6 to 7 days. The cells stimulated with Tct produced significant levels of IL-2. To determine which cells proliferated in response to Tct, PBMC were separated into T- and B-enriched cell populations. Purified T cells, but not B cells, proliferated strongly to Tct. The T cell response required APC and was processing dependent. T cell lines generated against Tct proliferated in response to parasite lysate only in the presence of autologous APC and produced IL-2, IL-6, and IFN-gamma but not IL-4 in response to PMA plus ionomycin. Although there were a significant number of CD45Ra+ cells, the majority of the cells in these T cell lines were CD45Ro+. The V beta usage of Tct-responding T cells was heterogeneous, with most V beta genes represented among the responding cells. An immunodominant repeat Ag (TcD) and a ribosomal phosphoprotein (P0) of T. cruzi elicited strong proliferative responses in all subjects tested. These data indicate the presence of T cell-stimulatory Ag in Tct, characterized by nonpreferential usage of the V beta gene families. The strong stimulation of normal human PBMC by Tct may contribute to immunologic alterations seen in T. cruzi infection.

Cyclophosphamide blocks both antigen-specific and polyclonal immunoglobulin responses in experimental visceral leishmaniasis

Cyclophosphamide (Cy) has been shown to modulate antibody responses in a wide range of diseases both in humans and experimental animals. Our results in Syrian hamsters infected with Leishmania donovani have shown that Cy blocks specific and polyclonal antibody production both in vivo and in vitro. This effect was achieved by weekly 100 mg/kg doses and also by a 300 mg/kg single dose. Although Cy provokes a significant decrease in B-cell numbers in infected animals, this cannot explain the suppression of antibody production since a 50% decrease in B-cells of only-infected hamsters did not reproduce the same effect in in vitro assays. Also, this suppression was not reversed either by elimination of adherent cells or by the presence of indomethacin. These data suggest that Cy affects T-cell populations involved in the control of antibody production by B-cells.