Physalin pool from Physalis angulata L. leaves and physalin D inhibit P2X7 receptor function in vitro and acute lung injury in vivo.

P2X7 receptor promotes inflammatory response and neuropathic pain. New drugs capable of impairing inflammation and pain-reducing adverse effects extracted from plant extracts have been studied. Physalis angulate L. possesses traditional uses and exhibits antiparasitic, anti-inflammatory, antimicrobial, antinociceptive, antimalarial, antileishmanial, immunosuppressive, antiasthmatic. diuretic, and antitumor activities. The most representative phytochemical constituents identified with medicinal importance are the physalins and withanolides. However, the mechanism of anti-inflammatory action is scarce. Although some physalins and withanolides subtypes have anti-inflammatory activity, only four physalins subtypes (B, D, F, and G) have further studies. Therefore, we evaluated the crude ethanolic extract enriched with physalins B, D, F, and G from P. angulata leaves, a pool containing the physalins B, D, F, G, and the physalins individually, as P2X7 receptor antagonists. For this purpose, we evaluated ATP-induced dye uptake, macroscopic currents, and interleukin 1-ß (IL-1ß) in vitro. The crude extract and pool dose-dependently inhibited P2X7 receptor function. Thus, physalin B, D, F, and G individually evaluated for 5'-triphosphate (ATP)-induced dye uptake assay, whole-cell patch-clamp, and cytokine release showed distinct antagonist levels. Physalin D displayed higher potency and efficacy than physalin B, F, and G for all these parameters. In vivo mice model as ATP-induced paw edema was potently inhibited for physalin D, in contrast to physalin B, F, and G. ATP and lipopolysaccharide (LPS)-induced pleurisy in mice were reversed for physalin D treatment. Molecular modeling and computational simulation predicted the intermolecular interactions between the P2X7 receptor and physalin derivatives. In silico results indicated physalin D and F as a potent allosteric P2X7 receptor antagonist. These data confirm physalin D as a promisor source for developing a new P2X7 receptor antagonist with anti-inflammatory action.

Lipoxin A(4) attenuates zymosan-induced arthritis by modulating endothelin-1 and its effects.

BACKGROUND AND PURPOSE: Lipoxin A(4) (LXA(4)) is a lipid mediator involved in the resolution of inflammation. Increased levels of LXA(4) in synovial fluid and enhanced expression of the formyl peptide receptor 2/lipoxin A(4) receptor (FPR2/ALX) in the synovial tissues of rheumatoid arthritis patients have been reported. Endothelins (ETs) play a pivotal pro-inflammatory role in acute articular inflammatory responses. Here, we evaluated the anti-inflammatory role of LXA(4), during the acute phase of zymosan-induced arthritis, focusing on the modulation of ET-1 expression and its effects. EXPERIMENTAL APPROACH: The anti-inflammatory effects of LXA(4), BML-111 (agonist of FPR2/ALX receptors) and acetylsalicylic acid (ASA) pre- and post-treatments were investigated in a murine model of zymosan-induced arthritis. Articular inflammation was assessed by examining knee joint oedema; neutrophil accumulation in synovial cavities; and levels of prepro-ET-1 mRNA, leukotriene (LT)B(4), tumour necrosis factor (TNF)-α and the chemokine KC/CXCL1, after stimulation. The direct effect of LXA(4) on ET-1-induced neutrophil activation and chemotaxis was evaluated by shape change and Boyden chamber assays respectively. KEY RESULTS: LXA(4), BML-111 and ASA administered as pre- or post-treatment inhibited oedema and neutrophil influx induced by zymosan stimulation. Zymosan-induced preproET-1 mRNA, KC/CXCL1, LTB(4) and TNF-α levels were also decreased after LXA(4) pretreatment. In vitro, ET-1-induced neutrophil chemotaxis was inhibited by LXA(4) pretreatment. LXA(4) treatment also inhibited ET-1-induced oedema formation and neutrophil influx into mouse knee joints. CONCLUSION AND IMPLICATION: LXA(4) exerted anti-inflammatory effects on articular inflammation through a mechanism that involved the inhibition of ET-1 expression and its effects.

Antiinflammatory effects of natural tetranortriterpenoids isolated from Carapa guianensis Aublet on zymosan-induced arthritis in mice.

OBJECTIVE: We investigated the antiinflammatory properties of a derived fraction of tetranortriterpenoids (TNTP) obtained from the seeds of Carapa guianensis Aublet. MATERIAL AND METHODS: Zymosan-induced arthritis and pleurisy in Swiss and C57/Bl6 mice (n = 10 per group). Western blot analysis was performed to analyze nuclear factor-kappaB (NFkappaB) translocation in mice peritoneal macrophages stimulated in vitro with zymosan (500 microg/ml). ELISA was performed to evaluate cytokine levels in knee joints. Values of p

Investigations on the anti-inflammatory and anti-allergic activities of the leaves of Uncaria guianensis (Aublet) J. F. Gmelin.

Uncaria guianensis (Aublet) J. F. Gmelin is an herbal medicine from tropical areas of South and Central America. We investigated the anti-inflammatory and anti-allergic properties of an ethanolic extract of U. guianensis leaves, containing alkaloids, flavonoids and phenol carboxylic acids, as revealed by thin layer chromatography (TLC). Oral pre-treatment with U. guianensis inhibited zymosan-induced paw oedema (500 mg/paw) and pleural exudation (100 mg/kg) within 4 h (25-200 mg/kg). U. guianensis (100 mg/kg) inhibited total leukocyte and neutrophil numbers in the pleural cavity 4 h after zymosan stimulation. Pre-treatment with U. guianensis (100 mg/kg, p.o.) inhibited total leukocyte, neutrophil and eosinophil recruitment into the pleural cavity 24 h after LPS (250 ng/cavity, i.t.). Pre-treatment with U. guianensis inhibited paw oedema (25-200 mg/kg) induced by ovalbumin (OVA) within 1 h, and neutrophil and eosinophil recruitment into the mice pleural cavity 24 h after OVA (100 mg/kg). In vitro data revealed that U. guianensis impaired LPS-induced nitric oxide and CXCL8 generation by murine peritoneal macrophages, as well as OVA-induced interleukin-5 synthesis by previously sensitized spleen cells. These results demonstrate that U. guianensis leaves provide effective anti-inflammatory and anti-allergic activities.

Anti-inflammatory and anti-ulcerogenic properties of Stachytarpheta cayennensis (L.C. Rich) Vahl.

In the present work, the anti-inflammatory and gastroprotective properties of ethanolic extracts of Stachytarpheta cayennesis (L.C. Rich) Vahl (Verbenaceae) were assessed. Chromatographic analysis of the crude ethanolic extract, SC01, revealed high concentrations of the iridoid ipolamiide, whereas the SC02, the second ethanolic extract, presented the arylpropanoid verbacoside as a major constituent. The oral administration of SC01 (100 mg/kg) into Swiss mice failed to inhibit paw oedema and pleural exudation induced by carrageenan and zymosan, whereas SC02 (100 mg/kg, p.o.) inhibited oedema and protein extravasation in all instances. Both extracts inhibited total leukocyte accumulation into the pleural cavity 4 and 24h after the intrathoracic (i.t.) injection of carrageenan, due to the inhibition of neutrophil and mononuclear cell influx, whereas only SC02 was able to inhibit leukocyte mobilization induced by zymosan (100 microg/cavity, i.t.). SC02 inhibited LPS (250 ng/cavity)-induced total leukocyte, neutrophil and eosinophil accumulation in the pleural cavity, whereas SC01 selectively inhibited neutrophil influx. In addition, our data indicates that the extract SC02 presents an important anti-ulcerogenic activity, since it inhibited diclofenac-induced (100 mg/kg, p.o.) gastric ulcera. Overall, these data provide evidence for the anti-inflammatory and gastroprotective properties of Stachytarpheta cayennensis, supporting its use in folk medicine for such purposes.

Anti-allergic effects of natural tetranortriterpenoids isolated from Carapa guianensis Aublet on allergen-induced vascular permeability and hyperalgesia.

OBJECTIVE: We investigated the anti-allergic and analgesic properties of an oil and a derived fraction of tetranortriterpenoids (TNTP) obtained from the seeds of Carapa guianensis Aublet. MATERIALS AND METHODS: Pleurisy, paw and ear edema were induced in Swiss and C57/Bl10 mice mice, whereas thermal hyperalgesia was assessed in Wistar rats (n = 6-10 per group). Values of p < 0.05 were regarded as significant. RESULTS: C. guianensis oil (100 to 400 mg/kg, p.o.) and TNTP (12.5 to 100 mg/kg, p.o.) inhibited pleural exudation, paw and ear edema induced by ovalbumin (OVA) in sensitized mice. TNTP (12.5 to 100 mg/kg, p.o.) also inhibited paw edema induced by histamine, PAF and bradykinin. TNTP (100 mg/kg, p.o.) inhibited prostaglandin E(2) generation in the pleural cavity in response to antigenic challenge. Moreover, C. guianensis oil (100 to 400 mg/kg) and TNTP (12.5 to 100 mg/kg) decreased OVA- and histamine-induced hyperalgesia. CONCLUSION: Taken together, these findings demonstrate the anti-edematogenic and analgesic effects of C. guianensis oil, and points out TNTP as the responsible bioactive compounds.

LPS induces eosinophil migration via CCR3 signaling through a mechanism independent of RANTES and Eotaxin.

Mounting evidence suggests that lipopolysaccharide (LPS) modulates bronchoconstriction and eosinophil function in asthma. We have investigated the role of different chemokines in the eosinophil influx to the pleural cavity after LPS stimulation. Expression of mRNA for eotaxin, regulated on activation, normal T cells expressed and secreted (RANTES), macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, MIP-2, and monocyte chemotactic protein (MCP)-1 was increased in cells recovered from the mouse pleural cavity 6 h after LPS administration. Eotaxin and RANTES, but not MIP-1alpha, protein levels were also increased in cell-free pleural washes recovered 6 h after LPS stimulation (LPW). Antimurine eotaxin and antimurine RANTES antibodies (Abs) failed to inhibit LPS-induced eosinophil influx into mouse pleural cavity in vivo. Pertussis toxin inhibited LPW-induced eosinophil shape change in vitro, suggesting the involvement of G protein-coupled receptors in LPW signaling. Blockade of CCR3 receptors diminished eosinophil shape change induced by LPW fractions in vitro and LPS-induced eosinophil accumulation in vivo. To investigate further contribution of CC chemokines, we administered a 35-kD CC chemokine neutralizing protein (vCKBP) in vivo. vCKBP inhibited the eosinophil accumulation induced by eotaxin and ovalbumin, but did not block that induced by LPS or LPW. Our data suggest that LPS-induced eosinophil accumulation depends on G protein-coupled CCR3 receptor activation, through a mechanism independent of eotaxin, RANTES, or other vCKBP-inhibitable CC chemokines.

Mechanisms of allergen- and LPS-induced bone marrow eosinophil mobilization and eosinophil accumulation into the pleural cavity: a role for CD11b/CD18 complex.

OBJECTIVE: The mechanisms involved in bone marrow eosinophil emigration and recruitment to inflammatory sites are not fully understood. The involvement of CD11b/CD18 in marrow eosinophil release induced by lipopolysaccharide (LPS) or allergen was investigated in mice. METHODS: Eosinophil and neutrophil counts in the pleural cavity, blood and bone marrow were performed at different time intervals after the intrathoracic injection of LPS (250 ng/cavity) or ovalbumin (OVA, 12 microg/cavity; into actively sensitized mice) and compared to anti-CD11b/CD 18 (5C6, 1 mg/mouse) or anti-IL-5 (TRFK-5, 500 microg/kg) treated mice. RESULTS: LPS induced local eosinophil influx, that peaked within 24 h and that was preceded by a decrease in marrow eosinophils at 4 h. Antigenic challenge induced a decrease in marrow eosinophils within 4 h, followed by a long lasting pleural eosinophil accumulation and a persistent increase in marrow eosinophil numbers. Pretreatment with anti-CD11b/CD18 abolished LPS-induced neutrophil and eosinophil accumulation in the pleural cavity at 4 and 24 h, respectively. This pretreatment failed to modify neutrophil emigration from bone marrow, but significantly inhibited marrow eosinophil release at 4 h post-LPS or OVA challenge. Anti-IL-5 pretreatment failed to inhibit LPS-induced pleural eosinophil accumulation and mobilization from bone marrow, but it abolished allergen-induced effects, indicating a role for IL-5 in marrow eosinophil mobilization induced by antigen, but not by LPS challenge. CONCLUSIONS: Our results suggest that eosinophil migration induced by antigen or LPS into the pleural cavity is preceded by bone marrow eosinophil release through a mechanism that depends on CD11b/CD18.

Excito-repellency effect of deltamethrin on triatomines under laboratory conditions.

This work demonstrates that deltamethrin in low doses produces an excito-repellency effect on triatomines, as already observed for mosquitoes. A wooden box covered with a cloth impregnated with deltamethrin at doses of 2.5 and 5mg ai/m2 was utilized for the experiment. The triatomine species studied were Triatoma infestans, Panstrongylus megistus, Rhodnius neglectus and Triatoma sordida. Adults were released in one of the sides of the box and their position was noted in subsequent periods. The observations were realized on the day the cloth was impregnated and subsequently repeated at 30 and 60 days for T. sordida; on day 120, the remaining species were included. Insect mortality and attempts at flight from the box were also observed. Excito-repellency was evident for all species and doses up to day 120. The only species that attempted to fly was P. megistus. The excito-repellency effect may be considered as an additional advantage to the insecticide power, as it should be able to prevent the installation of new colonies by females that fly into the homes, and at the moment of the spraying, it should promote the flushing out of triatomines from the wall crevices and from other shelters.

Comparative kinetics of bloodmeal intake by Triatoma infestans and Rhodnius prolixus, the two principal vectors of Chagas disease.

Chagas disease vector insects Triatoma infestans and Rhodnius prolixus (fifteen stage III nymphs per 4 litre cage) were allowed to feed on anaesthetized mice for 1 h (control group), or on active non-anaesthetized mice (NAM) for 2, 4 or 8 h exposure. The bloodmeal size (weight increase) for both species was proportional to the duration of contact with NAM, due to ingestion of multiple small bloodmeals, up to 142% of control weight for T. infestans with 8 h exposure to NAM. The mean weight increase of T. infestans nymphs after 4 h contact with NAM was similar to that of the control group, whereas for R. prolixus, 8 h contact with NAM gave only 64% of the control value. For both species of insect, within 4 h of feeding, > 20% of the bloodmeal weight was lost by defaecation and diuresis. The proportions of unfed nymphs and mortality during 2 h contact with NAM were significantly higher for R. prolixus, demonstrating better exploitation of the host blood source by T. infestans, apparently because during blood-feeding the latter insect species caused less irritation to the host.

The role of gammadelta T lymphocytes in lipopolysaccharide-induced eosinophil accumulation into the mouse pleural cavity.

LPS induces an accumulation of eosinophils in the pleural cavity that requires resident macrophages and lymphocytes, but is independent of IL-5 production. In the present study we investigated the involvement of different T lymphocyte subsets on the modulation of LPS-induced eosinophil accumulation into the pleural cavity of mice. Within 4 h after LPS injection the number of neutrophils in the pleural cavity increased significantly. Mononuclear cell counts increased after 12 h, while a significant rise on eosinophil counts was observed only after 24 h. T lymphocytes counts were increased in the pleural cavity 24 and 48 h after LPS administration. This T lymphocyte accumulation was accounted for by an influx of the gammadelta+ subset, while CD4+ and CD8+ subsets did not accumulate in the pleural cavity after LPS stimulation. All those changes had resolved 96 h after LPS injection. Depletion of T lymphocytes by treatment with mAb anti-Thy 1.0 inhibited the eosinophil accumulation triggered by LPS. Aiming to clarify which T lymphocyte subset would be involved in the LPS-induced eosinophil accumulation, we depleted mice of various T lymphocyte subpopulations using specific Abs. Depletion of either CD4+ or CD8+ subsets failed to inhibit LPS-induced eosinophil migration. In contrast, when mice were treated with anti-gammadelta+ T lymphocyte mAb, a significant reduction of LPS-induced eosinophil accumulation was observed. Similarly, the administration of LPS in BALB/c-nu/nu mice induced the expected significant influx of eosinophils into the pleural cavity. Our results indicate that the gammadelta+ T lymphocytes are centrally involved in LPS-induced eosinophil accumulation in mice.

A role for lymphocytes and cytokines on the eosinophil migration induced by LPS.

In the present work we review the existing evidence for a LPS-induced cytokine-mediated eosinophil accumulation in a model of acute inflammation. Intrathoracic administration of LPS into rodents (mice, rats or guinea pigs) induces a significant increase in the number of eosinophils recovered from the pleural fluid 24 hr later. This phenomenon is preceded by a neutrophil influx and accompanied by lymphocyte and monocyte accumulation. The eosinophil accumulation induced by LPs is not affected by inhibitors of cyclo or lipoxygenase nor by PAF antagonists but can be blocked by dexamethasone or the protein synthesis inhibitor cycloheximide. Transfer of cell-free pleural wash from LPS injected rats (LPS-PW) to naive recipient animals induces a selective eosinophil accumulation within 24 hr. The eosinophilotactic activity present on the LPS-PW has a molecular weight ranging between 10 and 50 kDa and its effect is abolished by trypsin digestion of the pleural wash indicating the proteic nature of this activity. The production of the eosinophilotactic activity depends on the interaction between macrophages and T-lymphocytes and its effect can not be blocked by anti-IL-5 monoclonal antibodies. Accumulated evidence suggest that the eosinophil accumulation induced by LPS is a consequence of a eosinophilotactic cytokine produced through macrophage and T-cell interactions in the site of a LPS-induced inflammatory reaction.

Anticoagulant activity of Triatoma infestans and Panstrongylus megistus saliva (Hemiptera/Triatominae).

Salivary gland extract of Triatoma infestans prolonged thrombin time, prothrombin time, and activated partial thromboplastin time, while salivary gland extract of Panstrongylus megistus delayed thrombin time and activated partial thromboplastin time. However, saliva of P. megistus prolonged activated partial thromboplastin time and saliva of T. infestans delayed activated partial thromboplastin time and prothrombin time. T. infestans saliva interferes particularly with activity of factor VIII (intrinsic pathway) and factor V (common pathway), but also affects other factors. Saliva of the triatomine species studied presented distinct SDS-PAGE profiles. These results demonstrate that there are differences in anticoagulant activity and protein composition of triatomine saliva.

Triatoma infestans is more efficient than Panstrongylus megistus in obtaining blood meals on non Anaesthetized mice

We compared the influence of the bug density in the capacity of Triatoma infestans and Panstrongylus megistus in obtaining blood meal in non anaesthetized mice. The regression anlysis for increase in body weight (mg) versus density (no. of bugs/mouse) showed that in experiments with anaesthetized mice (AM), no correlation was observed. In experiments with non anaesthetized mice (NAM) the weight increase was inversely proportional to density. The regression slope for blood meal size on density was less steep for T. infestans than for P. megistus (-1.9 and -3.0, respectively). The average weight increase of P. megistus nymphus in experiments with AM was higher than for T. infestans nymphs; however, in experiments with NAM such results were inverted. Mortality of P. megistus was significantly higher than of T. infestans with NAM. However, in experiments with AM very low mortality was observed. Considering the mortality and the slope of regression line on NAM, T. infestans is more efficient than P. megistus in obtaining blood meal in similar densities, possibly because it caused less irritation of the mice. The better exploitation of blood source of T. infestans when compared with P. megistus in similar densities, favours the maintenance of a better nutritional status in higher densities. This could explain epidemiological findings in which T. infestans not only succeeds in establishing larger colonies but also dislodges P. megistus in human dwellings when it is introduced in areas where the latter species prevails.

Triatoma infestans is more efficient than Panstrongylus megistus in obtaining blood meals on non anaesthetized mice.

We compared the influence of bug density in the capacity of Triatoma infestans and Panstrongylus megistus in obtaining blood meal in non anaesthetized mice. The regression analysis for increase in body weight (mg) versus density (no. of bugs/mouse) showed that in experiments with anaesthetized mice (AM), no correlation was observed. In experiments with non anaesthetized mice (NAM) the weight increase was inversely proportional to density. The regression slope for blood meal size on density was less steep for T. infestans than for P. megistus (-1.9 and -3.0, respectively). The average weight increase of P. megistus nymphs in experiments with AM was higher than for T. infestans nymphs; however, in experiments with NAM such results were inverted. Mortality of P. megistus was significantly higher than that of T. infestans with NAM. However, in experiments with AM very low mortality was observed. Considering the mortality and the slope of regression line on NAM, T. infestans is more efficient than P. megistus in obtaining blood meal in similar densities, possibly because it caused less irritation of the mice. The better exploitation of blood source of T. infestans when compared with P. megistus in similar densities, favours the maintenance of a better nutritional status in higher densities. This could explain epidemiological findings in which T. infestans not only succeeds in establishing larger colonies but also dislodges P. megistus in human dwellings when it is introduced in areas where the latter species prevails.

[Feeding and defecation dynamics of Triatoma sordida]. / Dinâmica da alimentação e dejeção do Triatoma sordida.

Today, Triatoma sordida is the most frequently captured triatomine in Brazil. For a better understanding of its vectorial potential, its feeding dynamics and dejections behaviour were studied in comparison with Triatoma infestans and P. megistus. The proportion of T. sordida and T. infestans that blood fed on anaesthetized rats did not differ significantly. There was no significant difference in the time elapse between release of the bugs and the initiation of blood feeding. The mean time between completion of a blood meal and the first dejection was significantly lower in T. infestans than in T. sordida. The numbers of insects that defecated during the blood meal or immediately afterwards was similar for both species. Approximately 80 specimens of each of T. sordida, T. infestans and Panstrongylus megistus were offered daily blood meals for 30 minutes, over a period of 30 days. T. sordida bit more frequently than did P. megistus and T. infestans. These data could indicate that T. sordida may not be completely adapted to its host and might have difficulty in complete its blood meal.

Requirement for lymphocytes and resident macrophages in LPS-induced pleural eosinophil accumulation.

In this study we investigated the involvement of inflammatory cells in the pleural accumulation of eosinophils induced by lipopolysaccharide (LPS). Intrathoracic (i.t.) injection of LPS (250 ng/cavity) into rats induced a significant eosinophil accumulation that developed within 24 h, was maximal at 48 h, and returned to control values within 120 h. This eosinophil influx was preceded by a huge neutrophil influx within 4 h and accompanied by a mononuclear cell accumulation between 24 and 48 h. Pretreatment with an antineutrophil monoclonal antibody (RP-3, 2 ml per animal) selectively reduced the number of circulating neutrophils within 8 h but failed to alter the LPS-induced eosinophilia. Similarly, platelet depletion with an anti-rat platelet antiserum did not alter the LPS-induced eosinophil accumulation. Cyclosporine (50 mg/kg, 12 and 2 h before) partially inhibited (51%) the LPS-induced pleural eosinophilia, whereas the eosinophilia was not changed by prior degranulation of pleural mast cells with polymyxin B (10 micrograms/cavity, 24 h before). Moreover, selective depletion of T lymphocytes using an anti-Thy 1.0 monoclonal antibody significantly inhibited the eosinophilia triggered by LPS. The i.t. injection of liposomes containing dichloromethylene diphosphonate significantly reduced (65%) the number of resident macrophages after 5 days. Under this condition, the eosinophil infiltration induced by LPS was completely inhibited. Accordingly, the i.t. injection of supernatant from macrophage monolayers, obtained from the pleural cavities of LPS-injected rats, into naive recipient animals led to a twofold increase in the number of pleural eosinophils. In conclusion, our data suggest an important role for resident macrophages and T lymphocytes in the eosinophil accumulation induced by LPS.

IL-5 accounts for the mouse pleural eosinophil accumulation triggered by antigen but not by LPS.

The involvement of interleukin-5 (IL-5) in the pleural eosinophilia induced by LPS or allergen was investigated. The number of pleural eosinophils in actively sensitized mice increased 24 h after the intrathoracic (i.t.) injection of ovalbumin (12 mg/cavity), peaked within 72 h, and persisted significantly increased for at least 120 h. Despite being less intense, the i.t. injection of LPS (250 ng/cavity) also increased the number of pleural eosinophils at 24 h, returning to basal levels within 72 h. Intraperitoneal pretreatment with monoclonal antibody to IL-5 (TRFK-4 and TRFK-5, 500 mg/kg) suppressed the eosinophil accumulation induced by IL-5 (200 units/cavity) or ovalbumin, but had no effect on the LPS-induced eosinophilia. Transfer of the cell-free pleural washing from LPS-treated donor mice to naive recipient animals led to a selective increase in the eosinophil counts. The co-incubation of the pleural washing from LPS-treated animals with monoclonal antibody to IL-5 failed to modify the phenomenon. The results indicate that IL-5 plays an important role in the antigen-induced accumulation of eosinophils in vivo, but not in the eosinophilia triggered by LPS.