Concanavalin A-induced Proliferation Research Articles

Insights into the radioprotective efficacy of Pterocarpus santalinus L. aqueous extract

In the present study, we have attempted a comprehensive assessment of the possible radioprotective efficacy of Pterocarpus santalinus aqueous extract (PSAE). All the studied models were gamma-irradiated with prior treatment with PSAE. First, the content of total phenols (4.061 μg/mg gallic acid equivalents), flavonoids (6.616 μg/mg quercetin equivalents), and tannins (0.008 mg/L of PSAE) were determined spectrophotometrically. Second, UHPLC-HRMS analysis was performed to identify the possible radioprotectors. Of those, santalins A & B are known for their usage as natural color in foods and alcoholic beverages identified in PSAE. Treatment was well tolerated with no side effects from PSAE. Later, it was shown that radiation-induced lethality significantly amended in PSAE-treated spleen lymphocytes as evidenced by reduced elevated levels of ROS and lipid peroxidation, restored total thiols and GSH: GSSG, inhibited DNA DSBs and cell death. Furthermore, an immunomodulation study was carried out because radiation exposure induces an inflammatory response. Our study shows that PSAE suppressed concanavalin A-induced T-cell proliferation as evidenced by CFSE dye dilution and CD69 antibody staining methods. Taken together, the current study explored the protective efficacy of PSAE from gamma radiation-inflicted injuries and hence we recommend PSAE as a potent radioprotective formulation.

How the immune mousetrap works: Structural evidence for the immunomodulatory action of a peptide from influenza NS1 protein

One of the critical stages of the T-cell immune response is the dimerization of the intramembrane domains of T-cell receptors (TCR). Structural similarities between the immunosuppressive domains of viral proteins and the transmembrane domains of TCR have led several authors to hypothesize the mechanism of immune response suppression by highly pathogenic viruses: viral proteins embed themselves in the membrane and act on the intramembrane domain of the TCRalpha subunit, hindering its functional oligomerization. It has also been suggested that this mechanism is used by influenza A virus in NS1-mediated immunosuppression. We have shown that the peptide corresponding to the primary structure of the potential immunosuppressive domain of NS1 protein (G51) can reduce concanavalin A-induced proliferation of PBMC cells, as well as in vitro, G51 can affect the oligomerization of the core peptide corresponding to the intramembrane domain of TCR, using AFM and small-angle neutron scattering.The results obtained using in cellulo and in vitro model systems suggest the presence of functional interaction between the NS1 fragment and the intramembrane domain of the TCR alpha subunit. We have proposed a possible scheme for such interaction obtained by computer modeling.This suggests the existence of another NS1-mediated mechanism of immunosuppression in influenza.

Discovery of Undescribed Monoterpenoid Polyprenylated Acylphloroglucinols with Immunosuppressive Activities from Hypericum longistylum

Acylphlorostylums A–G (1–7), seven undescribed monoterpenoid polyprenylated acylphloroglucinols, were isolated and identified from Hypericum longistylum. Significantly, acylphlorostylums A and B were the first monoterpenoid polyprenylated acylphloroglucinols possessing a dodecahydro-1H-benzo [b]cyclopenta [e]oxepine moiety bearing a 6/7/5 fused tricyclic ring system that assembled by the attack from 4-OH to C-13. In addition, acylphlorostylums A–G exhibited moderate in vitro immunosuppressive activity in anti-CD3/anti-CD28 monoclonal antibodies, lipopolysaccharide and concanavalin A-induced murine splenocyte proliferation, with IC50 values ranging from 1.51 ± 0.12 to 18.49 ± 1.67 μM, underscoring those isolates as novel chemical templates in the development of novel immunosuppressors.

Daily intake of heat-killed Lactobacillus plantarum L-137 improves inflammation and lipid metabolism in overweight healthy adults: a randomized-controlled trial

PurposeThe effects of heat-killed Lactobacillus plantarum L-137 (HK L-137) on inflammation and lipid metabolism were investigated in overweight volunteers.MethodsOne hundred healthy subjects with a body mass index from 23.0 to 29.9 (51 men and 49 women; mean age: 41.4 years) were enrolled in this randomized, double-blind, placebo-controlled, parallel group study. Subjects were randomly assigned to daily administration of a tablet containing HK L-137 (10 mg) or a placebo tablet for 12 weeks. Blood samples were collected every 4 weeks to measure biomarkers of lipid metabolism and inflammatory mediators.ResultsThe percent change of concanavalin A-induced proliferation of peripheral blood mononuclear cells was significantly larger in the HK L-137 group than in the control group, similar to previous studies. The decreases of aspartate aminotransferase and alanine aminotransferase over time were significantly larger in the HK L-137 group than in the control group, as were the decreases of total cholesterol, low-density lipoprotein cholesterol, and the leukocyte count at one time point. These effects of HK L-137 were stronger in the subjects with higher C-reactive protein levels.ConclusionsThese findings suggest that daily intake of HK L-137 can improve inflammation and lipid metabolism in subjects at risk of inflammation.

Immunomodulatory Effects of the Stout Camphor Medicinal Mushroom, Taiwanofungus camphoratus (Agaricomycetes)-Based Health Food Product in Mice.

Taiwanofungus camphoratus is a unique medicinal mushroom endemic to Taiwan, and it is used as a folk medicine in East Asian countries. The aim of the present study was to investigate the immunomodulatory effects of "leader Antrodia cinnamomea capsule" (LAC), a health food product containing solid-state cultivated mycelial powder of T. camphoratus. For the in vivo studies, mice were orally administered LAC (76, 250, and 760 mg/kg b.w.) for 30 days, and its effects on cell-mediated humoral immune function were examined. The results of the concanavalin A-induced splenic lymphocyte proliferation test showed that LAC significantly increased splenic lymphocyte proliferation compared with the control. In addition, serum hemolysin analysis showed that LAC treatment significantly increased the half value of serum hemolysin (HC50) in mice compared with the control. Moreover, treatment with LAC significantly increased the phagocytic index as measured by carbon clearance and natural killer cell activity. Taken together, these findings provide strong evidence that LAC can modulate immune function.

A new immunosuppressive pregnane glycoside from aqueous fraction of Epigynum cochinchinensis

Chemical investigation on the aqueous fraction of the stems of Epigynum cochinchinensis led to the isolation of a new pregnane glycoside named as epigycoside A (1) along with three known analogues (2–4). The structure of compound 1 was elucidated by means of spectroscopic techniques, including HRESIMS, and 1D and 2D NMR experiments. The immunosuppressive activity of 1 was evaluated by an in vitro model of concanavalin A-induced mice splenocytes proliferation. Compound 1 showed significant inhibitory activity in a dose-dependent manner, closer to the efficacy of positive control, dexamethasone, at a concentration of 50 μM.

Immunosuppressive C21 steroidal glycosides from the root of Cynanchum atratum

Six new C21 steroidal glycosides (1–6) and one dideoxysaccharide (7), named atratcynosides A–F and atratcynose A, were isolated from the 80% ethanol extract of the root of Cynanchum atratum, together with three known compounds (8–10). The structures of the new compounds were determined on the basis of extensive spectral analyses and qualitative chemical methods. All compounds were subjected to detect the immunosuppressive activities by an in vitro model of concanavalin A-induced proliferation of T-lymphocytes from mice. Compounds 1–3 showed significant immunosuppressive activities in dose-dependent manners with the IC50 values from 3.3 to 7.0μM. Moreover, the structure–activity relationship of the steroidal glycosides on the immunosuppression was analyzed.

Immunomodulatory activity and partial characterisation of polysaccharides from Momordica charantia.

Momordica charantia Linn. is used as an edible and medicinal vegetable in sub-tropical areas. Until now, studies on its composition and related activities have been confined to compounds of low molecular mass, and no data have been reported concerning the plant’s polysaccharides. In this work, a crude polysaccharide of M. charantia (MCP) fruit was isolated by hot water extraction and then purified using DEAE-52 cellulose anion-exchange chromatography to produce two main fractions MCP1 and MCP2. The immunomodulatory effects and physicochemical characteristics of these fractions were investigated in vitro and in vivo. The results showed that intragastric administration of 150 or 300 mg·kg−·d−1 of MCP significantly increased the carbolic particle clearance index, serum haemolysin production, spleen index, thymus index and NK cell cytotoxicity to normal control levels in cyclophosphamide (Cy)-induced immunosuppressed mice. Both MCP1 and MCP2 effectively stimulated normal and concanavalin A-induced splenic lymphocyte proliferation in vitro at various doses. The average molecular weights of MCP1 and MCP2, which were measured using high-performance gel permeation chromatography, were 8.55 × 104 Da and 4.41 × 105 Da, respectively. Both fractions exhibited characteristic polysaccharide bands in their Fourier transform infrared spectrum. MCP1 is mainly composed of glucose and galactose, and MCP2 is mainly composed of glucose, mannose and galactose. The results indicate that MCP and its fractions have good potential as immunotherapeutic adjuvants.

Luteal cells from functional and regressing bovine corpora lutea differentially alter the function of gamma delta T cells.

The luteal microenvironment is thought to direct the function of resident immune cells to facilitate either luteal function or regression. To determine if luteal cells from functional (Days 10-12) and regressing (8 h after administration of prostaglandin F2alpha) corpora lutea (CL) induce different responses in γδ T cells, luteal cells were cocultured with autologous γδ T cells isolated from peripheral blood. Proliferation, functional phenotypes, and cytokine synthesis were analyzed by flow cytometry. To determine if the luteal cells from functional CL induce hyporesponsiveness in γδ T cells, γδ(+) cells were cocultured with midcycle luteal cells and further stimulated with concanavalin A. Coculture of γδ(+) cells with midcycle luteal cells did not inhibit concanavalin A-induced proliferation. In a proliferation assay, luteal cells from midcycle CL predominantly induced proliferation of γδ(+) WC1(-) cells (P < 0.05), while luteal cells from regressing CL predominantly induced proliferation of γδ(+)WC1(+) cells (P < 0.05). Analysis of intracellular cytokines indicated that midcycle luteal cells increased the proportion of γδ(+) cells containing interleukin 10 (P < 0.05), but reduced the proportion of γδ(+) cells containing interferon gamma (IFNG; P < 0.05). There were no changes in the proportions of γδ(+) cells synthesizing interleukin 4 or tumor necrosis factor. Unexpectedly, coculture of γδ(+) cells with luteal cells from regressing CL had no effect on any of the cytokines analyzed. These data support the hypothesis that the function of resident T cells is differentially modulated depending on the status of the CL.

Curcumin ameliorates rat experimental autoimmune neuritis

Experimental autoimmune neuritis (EAN) is a helper T cell-mediated autoimmune demyelinating inflammatory disease of the peripheral nervous system that serves as an animal model for human Guillain-Barre syndrome. Curcumin, a naturally occurring polyphenolic phytochemical isolated from the medicinal plant Curcuma longa, has anti-inflammatory activities. Here we investigated the therapeutic effects and potential mechanisms of curcumin in EAN rats. Exogenous curcumin treatment (100 mg/kg/day) significantly delayed the onset of EAN neurological signs, ameliorated EAN neurological severity, and reduced body weight loss of EAN rats. In EAN sciatic nerves, curcumin treatment suppressed the inflammatory cell accumulation and the expression of interferon (IFN)-γ, tumor necrosis factor-α, interleukin (IL)-1β, and IL-17. Furthermore, curcumin treatment significantly decreased the percentage of CD4(+) T helper cells in EAN spleen and suppressed concanavalin A-induced lymphocyte proliferation in vitro. In addition, curcumin altered helper T cell differentiation by decreasing IFN-γ(+) CD4(+) Th1 cells in EAN lymph node and spleen. In summary, our data demonstrate that curcumin could effectively suppress EAN by attenuating inflammation, indicating that curcumin might be a candidate for treatment of autoimmune neuropathies.

Dietary Curcuma longa enhances resistance against Eimeria maxima and Eimeria tenella infections in chickens

The effects of dietary supplementation with an organic extract of Curcuma longa on systemic and local immune responses to experimental Eimeria maxima and Eimeria tenella infections were evaluated in commercial broiler chickens. Dietary supplementation with C. longa enhanced coccidiosis resistance as demonstrated by increased BW gains, reduced fecal oocyst shedding, and decreased gut lesions compared with infected birds fed a nonsupplemented control diet. The chickens fed C. longa-supplemented diet showed enhanced systemic humoral immunity, as assessed by greater levels of serum antibodies to an Eimeria microneme protein, MIC2, and enhanced cellular immunity, as measured by concanavalin A-induced spleen cell proliferation, compared with controls. At the intestinal level, genome-wide gene expression profiling by microarray hybridization identified 601 differentially expressed transcripts (287 upregulated, 314 downregulated) in gut lymphocytes of C. longa-fed chickens compared with nonsupplemented controls. Based on the known functions of the corresponding mammalian genes, the C. longa-induced intestinal transcriptome was mostly associated with genes mediating anti-inflammatory effects. Taken together, these results suggest that dietary C. longa could be used to attenuate Eimeria-induced, inflammation-mediated gut damage in commercial poultry production.

Preventive effect of pidotimod on reactivated toxoplasmosis in mice

As one of food-borne parasitic diseases, toxoplasmosis entails the risk of developing reactivation in immunocompromised patients. The synthetic dipeptide pidotimod is a potent immunostimulating agent that improves the immunodefenses in immunodepression. To investigate the efficacy of pidotimod as a preventive treatment, we used a murine model of reactivated toxoplasmosis with cyclophosphamide (CY)-induced immunosuppression. Pidotimod administration significantly restored the body weight and spleen organ index, increased survival time (from 70 to 90%), and decreased the parasitemia (from 80 to 35%) of CY-induced mice with reactivated toxoplasmosis. Cytokine profiles and CD4(+) T cells subpopulation analyses by Cytometric Bead Array and flow cytometry demonstrated that pidotimod treatment resulted in a significant upregulation of pro-inflammatory cytokines (IFN-γ, TNF-α, and IL-2) and Th1 cells (from 3.73 ± 0.39 to 5.88 ± 0.46%) after CY induction in infected mice. Additionally, histological findings and parasite DNA quantification revealed that mice administered with pidotimod had a remarkable reduction of parasite burden (two-log) and amelioration of histopathology in the brains. The in vitro studies showed that pidotimod significantly restored concanavalin A-induced splenocyte proliferation and pro-inflammatory cytokines in the supernatants of splenocyte culture. It could be concluded that the administration of pidotimod in immunocompromised mice significantly increases the Th1-biased immune response, prolongs survival time, and ameliorates the load of parasites in the blood. This is the first report of the preventive effect of pidotimod on reactivated toxoplasmosis.

Babesia bovis:lipids from virulent S2P and attenuated R1A strains trigger differential signalling and inflammatory responses in bovine macrophages

The intra-erythrocytic protozoan Babesia bovis is an economically important pathogen that causes an acute and often fatal infection in adult cattle. Babesiosis limitation depends on the early activation of macrophages, essential cells of the host innate immunity, which can generate an inflammatory response mediated by cytokines and nitric oxide (NO). Herein, we demonstrate in bovine macrophages that lipids from B. bovis attenuated R1A strain (LA) produced a stronger NO release, an early TNFα mRNA induction and 2-fold higher IL-12p35 mRNA levels compared to the lipids of virulent S2P strain (LV). Neither LA nor LV induced anti-inflammatory IL-10. Regarding signalling pathways, we here report that LA induced a significant phosphorylation of p38 and extracellular signal-regulated kinases 1 and 2 (ERK1/2) whereas LV only induced a reduced activation of ERK1/2. Besides, NF-κB was activated by LA and LV, but LA produced an early degradation of the inhibitor IκB. Interestingly, LV and the majority of its lipid fractions, exerted a significant inhibition of concanavalin A-induced peripheral blood mononuclear cell proliferation with respect to LA and its corresponding lipid fractions. In addition, we determined that animals infected with R1A developed a higher increase in IgM anti-phosphatidylcholine than those inoculated with S2P. Collectively, S2P lipids generated a decreased inflammatory response contributing to the evasion of innate immunity. Moreover, since R1A lipids induced a pro-inflammatory profile, we propose these molecules as good candidates for immunoprophylactic strategies against babesiosis.

Oral intake of heat-killed Lactobacillus plantarum L-137 decreases the incidence of upper respiratory tract infection in healthy subjects with high levels of psychological stress.

The immunomodulatory effects of live or non-viable lactic acid bacteria have been extensively investigated. We reported that oral intake of heat-killed Lactobacillus plantarum L-137 (HK L-137) augmented innate and acquired immunity in mice and human subjects. To examine the effects of HK L-137 intake on upper respiratory tract infection (URTI) symptoms and immune functions in human subjects, a randomised, double-blind, placebo-controlled, parallel study was conducted in subjects with high psychological stress levels. A total of seventy-eight healthy subjects (thirty-three men and forty-five women; mean age 50·6 years) with scores of>41 on eighteen-item subscales of psychological distress in the Brief Job Stress Questionnaire were randomly assigned to receive a tablet containing HK L-137 (10mg) or a placebo tablet daily for 12 weeks. The URTI symptoms were rated once daily on the validated twenty-one-item Wisconsin Upper Respiratory Symptom Survey-21. Immune functions, such as concanavalin A-induced proliferation and percentages of interferon (IFN)-γ- and IL-4-producing CD4 T cells of peripheral blood mononuclear cells (PBMC), and serum IFN-β concentrations were measured every 4 weeks. URTI incidence was significantly lower in the HK L-137 group than in the control group. URTI incidence, duration and severity, and duration of medication showed significant negative correlations with duration of HK L-137 intake. The percentage change from baseline of concanavalin A-induced proliferation of PBMC was significantly greater in the HK L-137 group than in the control group. These findings suggest that daily HK L-137 intake can decrease URTI incidence in healthy subjects, possibly through augmentation of immune functions.

Alteration of immune function endpoints and differential expression of estrogen receptor isoforms in leukocytes from 17β-estradiol exposed rainbow trout (Oncorhynchus mykiss)

While the endocrine system is known to modulate immune function in vertebrates, the role of 17β-estradiol (E2) in cellular immune function of teleosts is poorly understood. The cellular and molecular responses of juvenile rainbow trout (Oncorhynchus mykiss) to E2 treatment were evaluated by exposing fish to 0.47±0.02μg/L E2 (mean±SEM) for either 2 or 7d, with a subsequent 14d recovery period. After 2 and 7d of exposure to E2, hematocrit was significantly lower than in control fish. Lipopolysaccharide-induced lymphocyte proliferation was elevated on day 2 and concanavalin A-induced lymphocyte proliferation was reduced following 7d of E2 exposure. Four estrogen receptor (ER) transcripts were identified in purified trout head kidney leukocytes (HKL) and peripheral blood leukocytes (PBL). While the mRNA abundance of ERβ1 and ERβ2 was unaffected by treatment, ERα1 was up-regulated in HKL and PBL following 7d of E2 exposure. ERα2 was up-regulated in HKL after 7d of E2 exposure, but down-regulated in PBL after 2 and 7d of treatment. All parameters that were altered during the E2 exposure period returned to baseline levels following the recovery period. This study reports the presence of the full repertoire of ERs in purified HKL for the first time, and demonstrates that ERα transcript abundance in leukocytes can be regulated by waterborne E2 exposure. It also demonstrated that physiologically-relevant concentrations of E2 can modulate several immune functions in salmonids, which may have widespread implications for xenoestrogen-associated immunotoxicity in feral fish populations inhabiting contaminated aquatic environments.

Restoration of electric footshock-induced immunosuppression in mice by Gynostemma pentaphyllum components.

The immunomodulatory effects of the ethanol extract of Gynostemma pentaphyllum (GP-EX) were examined in electric footshock (EFS)-stressed mice. The mice were orally administered various doses of GP-EX for 7 days before exposure to EFS (duration: 3 min, interval: 10 s, intensity: 2 mA) once a day from day 8 for 14 days with continuous daily feeding of GP-EX. Oral administration of GP-EX to mice prevented EFS stress-induced immunosuppression as determined by the lymphoid organ (thymus and spleen) weight and cellularity. In addition, oral administration of GP-EX restored EFS-suppressed functional properties of mature lymphocytes in terms of concanavalin A-induced proliferation of splenocytes and lipopolysaccharide-induced cytokine production (TNF-α, IL-1β). Furthermore, we found that mice that were orally administered with GP-EX generated much more potent ovalbumin-specific cytotoxic T lymphocyte responses upon intravenous ovalbumin injection compared to the untreated controls. These results demonstrate that oral administration of the ethanol extract of Gynostemma pentaphyllum could increase host defense in immunocompromised situations such as stress-induced immunosuppression.

Structural features and immunomodulatory activities of polysaccharides of longan pulp.

An aqueous extract of polysaccharides from longan pulp was chromatographed on a DEAE anion-exchange column to yield four fractions (LPI-IV). Immunomodulatory activities of these polysaccharides were also evaluated in vitro. The purified products, neutral polysaccharide LPI, polysaccharide-protein complex LPII and acidic polysaccharides LPIII and LPIV, exhibited conspicuous differences in their monosaccharide composition, molecular mass and glycosidic linkages. Except for LPI, the other three significantly stimulated lymphocyte proliferation in the dose range of 100-400μg/mL compared with the normal control (P<0.05), and might electively stimulate B cells, but not T cells. Furthermore, their stimulations on normal/lipopolysaccharide-induced proliferation and depressions on concanavalin A-induced proliferation could be ordered as LPIII>LPIV>LPII>LPI. All the fractions had the optimal dose of 100μg/mL on enhancing macrophage phagocytosis. Among them, LPII had the considerable yield and activity for exploiting as a potential immunoadjuvant.

Effect of heat challenge on peripheral blood mononuclear cell viability: comparison of a tropical and temperate pig breed

We evaluated the effect of heat challenge on cell viability, concanavalin A-induced proliferation and heat shock protein (HSPs) mRNA expression in peripheral mononuclear blood cells (PBMC) isolated from Creole (CR) and Large White (LW) pigs. The PBMCs were cultured for 9 h at 37 °C before being subjected to heat challenge: (1) at 42 °C or 45 °C for 2, 4, 6 and 9 h to monitor cell viability;(2) at 45 °C for 2 and 9 h followed by stimulation for 24 h at 37 °C with concanavalin A to evaluate mitogen-induced proliferation; and (3) at 45 °C for 3, 6 and 9 h to measure induction of HSP70.2 and HSP90 mRNA. Cell viability was affected by breed and temperature (P < 0.01), and the viability decrease caused by heat challenge was greater for LW than CR pigs. For mitogen-stimulated PBMCs, incubation at 45 °C reduced lymphoblastogenesis equally in both breeds (P < 0.01). Although heat challenge for 3 and 6 h at 45°C induced expression of HSP70.2 and HSP90 mRNA, no breed difference was observed. In conclusion, differences in heat resistance between these two breeds at the whole organism level are reflected at the cellular level. Neither HSP70.2 nor HSP90 mRNA expression levels explain this effect.

Dietary astaxanthin enhances immune response in dogs

No information is available on the possible role of astaxanthin on immune response in domestic canine. Female Beagle dogs (9–10mo old; 8.2±0.2kg body weight) were fed 0, 10, 20 or 40mg astaxanthin daily and blood sampled on wk 0, 6, 12, and 16 for assessing the following: lymphoproliferation, leukocyte subpopulations, natural killer (NK) cell cytotoxicity, and concentrations of blood astaxanthin, IgG, IgM and acute phase proteins. Delayed-type hypersensitivity (DTH) response was assessed on wk 0, 12 and 16. Plasma astaxanthin increased dose-dependently and reached maximum concentrations on wk 6. Dietary astaxanthin enhanced DTH response to vaccine, concanavalin A-induced lymphocyte proliferation (with the 20mg dose at wk 12) and NK cell cytotoxic activity. In addition, dietary astaxanthin increased concentrations of IgG and IgM, and B cell population. Plasma concentrations of C reactive protein were lower in astaxanthin-fed dogs. Therefore, dietary astaxanthin heightened cell-mediated and humoral immune response and reduced DNA damage and inflammation in dogs.

Composition and Systemic Immune Activity of the Polysaccharides from an Herbal Tea (Lycopus lucidusTurcz)

This study was undertaken to characterize the water-soluble polysaccharides isolated from an herbal tea, the leaves of L. lucidus Turcz. HPLC analysis showed that L. lucidus polysaccharides (LLPs) were mainly composed of galactose (50.1 mol %), followed by galacturonic acid (14.2 mol %), accounting for 64.3 mol % of all quantitative nine monosaccharides. Furthermore, we evaluated the systemic immunological efficacy of LLPs in mice. Mice were intragastrically administered once daily with low-dose (50 mg/kg), intermediate-dose (100 mg/kg), and high-dose (300 mg/kg) of LLPs, respectively, for 30 consecutive days. In comparison with vehicle, LLPs significantly enhanced the plaque-forming cells (PFCs), and serum hemolysin level, and delayed-type hypersensitivity (DTH) in response to sheep red blood cells (SRBC) in a dose-dependent manner (p < 0.01). In LLPs-treated mice, phagocytosis capacity and concanavalin A-induced spleenocyte proliferation were remarkably increased (p < 0.05). The intermediate- and high-dose of LLPs also caused a significant increase in the indices of thymus and spleen organs of mice (p < 0.05). This suggests that the polysaccharides derived from the tea leaves of L. lucidus improves the immune system and might be regarded as a biological response modifier.