Spleen Cell Cultures Research Articles

Development of an Adjuvant-Free Cashew Nut Allergy Mouse Model

Background: Cashew nut allergy is an emerging food allergy with a high risk of systemic anaphylaxis. Currently, an adjuvant-free animal model to study cashew nut allergy is not available. Methods: BALB/c mice were exposed to cashew nut protein using a transdermal sensitization protocol that does not use adjuvant. Systemic IgE antibody response, systemic anaphylaxis to oral challenge and allergen-driven, spleen-cell, type-2 cytokine responses were studied. Results: Transdermal exposure to cashew nut resulted in a significant dose-dependent allergic response. Oral challenge of sensitized mice with cashew resulted in severe signs of systemic anaphylaxis and a significant hypothermia. Spleen cell culture with cashew nut protein resulted in allergen-driven IL-4, IL-5 and IL-13 responses only in sensitized but not in saline control mice. Conclusions: These data demonstrate that (i) transdermal exposure to cashew nut protein elicits a robust IgE response leading to clinical sensitization of mice for systemic anaphylaxis to oral cashew nut challenge; (ii) cashew nut is a potent activator of type-2 cytokines, thus explaining the mechanism of cashew allergy, and (iii) this mouse model may be useful for further basic and preclinical studies on cashew nut allergy.

Immunomodulatory Effects of Egg White Enzymatic Hydrolysates Containing Immunodominant Epitopes in a BALB/c Mouse Model of Egg Allergy

Egg has ben documented as a rich source for the supply of biologically active peptides. This study characterizes the immunomodulatory effects of an egg white enzymatic hydrolysate (EWH) using a BALB/c mouse model of egg allergy. Mice were orally sensitized to egg white and subsequently gavaged with EWH. ELISA results indicated significant reductions of both serum histamine and specific IgE titers in EWH-fed mice, accompanied by a repression of both IL-4 and IFN-gamma production in spleen cell cultures. Similarly, real-time RT-PCR analyses highlighted decreased mRNA expression of IFN-gamma and IL-12 (Th1-biased), as well as lower ratios of IL-4 and IL-13 mRNA (Th2-biased). On the other hand, increased intestinal expressions of TGF-beta and FOXp3 mRNA were determined in EWH-fed mice, suggesting induction of local regulatory mechanisms. The presence of immunodominant epitopes was proposed to be responsible for the immunomodulatory effects observed.

Experimental infection with Leishmania chagasi in immunosuppressed Balb/c mice: cytokines and parasite burdens

The immune response in leishmaniasis may result in a polarization of the T lymphocyte subpopulation, altering cell phenotype and resulting in immune protection or disease exacerbation. Leishmania may persist in the body either during asymptomatic infections or after treatment, which represents high risk under immunosuppression. The objective of this study was to evaluate the effect of infection with immunosuppression by dexamethasone associated with pentoxifylline on animal weight, spleen weight, spleen and hepatic parasitic load and immunopathology, as well as the IFN-γ and IL-10 production in spleen cell culture of Balb/c mice infected with Leishmania chagasi. The infection did not cause body weight gain in animals, but both the weight and size of the spleen were increased. The immunosuppression using dexamethasone associated with pentoxifylline affected body weight gain and spleen weight and size in both infected and non-infected animals. The immunosuppression did not significantly alter the course of the splenic or hepatic parasite burden. Dexamethasone and pentoxifylline significantly affected cytokine production, but did not influence the Th1/Th2 ratio in infected animals.

Characterization of a Cellular Immunostimulating Peptide from a Soybean Protein Fraction Digested with Peptidase R

An immunostimulating glutamine-rich peptide was purified from a soybean protein fraction digested with Peptidase R produced by Rhizopus oryzae (Ro-digest) by a combination of SP-Sepharose column chromatography and reversed-phase high-performance liquid chromatography. The purified peptide was supposed to be located at or near the glutamine-rich region 202 to 222 of the glycinin G4 subunit. The peptide significantly increased the number of CD8(+), CD11b(+), and CD49b(+) cells in C3H/HeN mouse spleen cell cultures, while 2 chemically synthesized glutamine-rich peptides corresponding to residues 202 to 213 (QQQQQQKSHGGR) and residues 214 to 225 (KQGQHQQEEEEE) of the glycinin G4 subunit increased the number of interleukin (IL)-12(+)CD11b(+) cells. The peptide 202-213 also significantly increased the number of CD49b(+), IL-2(+)CD4(+), and interferon-gamma(+)CD4(+) cells and stimulated the cytotoxic activity of spleen cells toward the human erythroleukemia cell line K562. These results indicate that the glutamine-rich region of the soybean glycinin G4 subunit stimulates the cellular immune system in mouse spleen cell cultures.

Oligodeoxyribonucleotide-Based Antagonists for Toll-Like Receptors 7 and 9

Oligodeoxyribonucleotides containing unmethylated CpG motifs act as TLR9 agonists. In this study, we evaluated oligonucleotides containing an unmethylated CpG motif in which two nucleotides adjacent to the CpG dinucleotide were substituted with 2'-O-methylribonucleotides, resulting in TLR7 and TLR9 antagonists. In mouse and human cell cultures, antagonists did not stimulate immune activation but inhibited TLR7 and TLR9 agonist-induced activity. In mice, antagonists inhibited immune responses induced by TLR9 agonists for up to several days, and the inhibition was dose-dependent. Antagonists also inhibited immune responses induced by an RNA-based TLR7/8 agonist but not TLRs 2, 3, 4, or 5 agonists in mice. Additionally, antagonist inhibited TLR9 agonist-induced IL-6 in lupus-prone MRL/lpr mouse spleen cell cultures. These results indicate that antagonists described herein can suppress immune responses induced by TLR7 and TLR9 agonists. Antagonists may be suitable candidates for treating inflammatory and autoimmune diseases where inappropriate or uncontrolled TLR activation has been implicated.

Effects ofBifidobacterium animalisadministered during lactation on allergic and autoimmune responses in rodents

Probiotics are promoted as being beneficial to health and positive effects on the immune system have been reported. Beneficial immune effects have been attributed to several mechanisms, including stimulating T helper 1 (Th1) immunity. To explore the effects of the probiotic Bifidobacterium animalis on Th1- and Th2-mediated immune responses, two different animal models representing either Th1- or Th2-mediated immune responses were used: a rat model for experimental autoimmune encephalomyelitis (EAE) (Th1) and a mouse model for respiratory allergy induced by ovalbumin (OVA) (Th2). B. animalis administration started when the mice or rats were 2 weeks old. Respiratory allergy or EAE were induced when the animals were 6-7 weeks old. In the allergy model, B. animalis modestly reduced the number of infiltrating eosinophils and lymphocytes in the lungs, but no effects on allergen-specific serum immunoglobulin E levels were found. Cytokine profiles assessed after culturing spleen cells with the mitogen concanvalin A (ConA) showed that B. animalis skewed the Th1/Th2 balance towards Th1 in females. However, allergen-induced cytokine production in females was not affected by B. animalis. In males, B. animalis significantly decreased ConA-induced interleukin-13 and a trend towards lower levels of OVA-induced Th2 cytokines. In the EAE model, B. animalis significantly reduced the duration of clinical symptoms by almost 2 days in males and improved the body weight gain during the experimental period compared with the control group. Our data show that B. animalis reduced several immune parameters in the allergy as well as in the autoimmunity model.

Immunoregulation by Toxoplasma gondii infection prevents allergic immune responses in mice

Toxoplasma gondii is a ubiquitous intracellular parasite affecting most mammals including humans. In epidemiological studies, infection with T. gondii and allergy development have been postulated to be inversely related. Using a mouse model of birch pollen allergy we investigated whether infection with T. gondii influences allergic immune responses to birch pollen. BALB/c mice were infected with T. gondii oocysts either before or at the end of sensitisation with the major birch pollen allergen Bet v 1 and thereafter aerosol challenged with birch pollen extract. During the acute phase of infection, clinical signs correlated with increased levels of serum TNF-α, IL-6, IFN-γ and anti- Toxoplasma-IgM. In the chronic phase, Toxoplasma-specific serum IgG, brain tissue cysts and high IFN-γ production in spleen cell cultures were detected. Mice infected prior to allergic sensitisation produced significantly less allergen-specific IgE and IgG1, while IgG2a levels were markedly increased. IL-5 levels in spleen cell cultures and bronchoalveolar lavage fluid were significantly reduced, and airway inflammation was prevented in these mice. Notably, in mice infected at the end of the allergic sensitisation process, systemic and local immune responses to the allergen were markedly reduced. T. gondii infection was associated with up-regulation of Toll-like receptor 2 (TLR2), 4, 9 and 11, as well as T-bet (a differentiation factor for Th1 cells) mRNA expression in splenocytes; moreover, enhanced TGF-β, IL-10 and Foxp3 mRNA expression in these cells suggested that regulatory mechanisms were involved in suppression of the allergic immune response. Kinetic studies confirmed the induction of Foxp3 +CD4 +CD25 + regulatory T cells preferentially during the chronic phase of T. gondii infection. Our data demonstrate that T. gondii exhibits strong immunomodulating properties which lead to prevention of allergic immune responses and thereby support the hygiene hypothesis.

Long‐term administration of IgG2a anti‐NK1.1 monoclonal antibody ameliorates lupus‐like disease in NZB/W mice in spite of an early worsening induced by an IgG2a‐dependent BAFF/BLyS production

The role of natural killer (NK) T cells in the development of lupus-like disease in mice is still controversial. We treated NZB/W mice with anti-NK1.1 monoclonal antibodies (mAbs) and our results revealed that administration of either an irrelevant immunoglobulin G2a (IgG2a) mAb or an IgG2a anti-NK1.1 mAb increased the production of anti-dsDNA antibodies in young NZB/W mice. However, the continuous administration of an anti-NK1.1 mAb protected aged NZB/W mice from glomerular injury, leading to prolonged survival and stabilization of the proteinuria. Conversely, the administration of the control IgG2a mAb led to an aggravation of the lupus-like disease. Augmented titres of anti-dsDNA in NZB/W mice, upon IgG2a administration, correlated with the production of BAFF/BLyS by dendritic, B and T cells. Treatment with an anti-NK1.1 mAb reduced the levels of interleukin-16, produced by T cells, in spleen cell culture supernatants from aged NZB/W. Adoptive transfer of NK T cells from aged to young NZB/W accelerated the production of anti-dsDNA in recipient NZB/W mice, suggesting that NK T cells from aged NZB/W are endowed with a B-cell helper activity. In vitro studies, using purified NK T cells from aged NZB/W, showed that these cells provided helper B-cell activity for the production of anti-dsDNA. We concluded that NK T cells are involved in the progression of lupus-like disease in mature NZB/W mice and that immunoglobulin of the IgG2a isotype has an enhancing effect on antibody synthesis due to the induction of BAFF/BLyS, and therefore have a deleterious effect in the NZB/W mouse physiology.

Telithromycin inhibits the production of proinflammatory mediators and the activation of NF-κB inin vitro-stimulated murine cells

Telithromycin is a ketolide antibiotic with anti-inflammatory properties. To investigate the mechanisms of these effects, we examined the in vitro immunomodulatory activity of telithromycin on murine splenocytes and the murine macrophage cell line RAW 264.7. Spleen cells from BALB/c-untreated mice and RAW 264.7 macrophages were cultured in the presence of telithromycin. Proliferation and apoptosis (colorimetric assay), and cytokine production (enzyme immunoassay) of spleen cells in response to lipopolysaccharide and concanavalin A (Con A), and nitric oxide (NO) (colorimetric assay) and cytokine production by lipopolysaccharide-stimulated RAW 264.7 cells were determined. Telithromycin moderately enhanced lymphocyte proliferation in response to lipopolysaccharide and Con A, and enhanced apoptosis induced by camptothecin in mitogen-stimulated splenocytes. Con A-induced IFN-gamma production was suppressed and lipopolysaccharide-induced IL-10 production was increased in spleen cell cultures with telithromycin. Lipopolysaccharide-induced secretion of NO and tumor necrosis factor-alpha (TNF-alpha) was suppressed by telithromycin in RAW 264.7 cultures. Lipopolysaccharide-induced activation of NF-kappaB transcription factor and TNF-alpha promoter in RAW 264.7 macrophages transitorily transfected with luciferase reporter constructs was also inhibited by the ketolide. The suppressive effect of telithromycin on NF-kappaB activation was confirmed by Western blot and enzyme immunoassay. These results suggest that telithromycin exerts anti-inflammatory activity mediated by the inhibition of activation of NF-kappaB.

Influence of the Ity/Lsh/Bcg gene on the development of suppressor cell precursors in the early phase of the infection of mice with Mycobacterium lepraemurium.

In vitro inducible suppressor cell precursors were detected in the spleen of BALB/c but not in DBA/2 mice infected intraperitoneally with 10(8) Mycobacterium lepraemurium bacilli, thus suggesting that their development is genetically controlled. Two pairs of mouse strains congenic at the Ity/Lsh/Bcg locus (BALB/c-C.D2 and B10.A-B10.A.Bcgr) were used to investigate whether this phenomenon is influenced by this gene known to control the relative susceptibility of mice to Myco. lepraemurium infection. This seems likely, as the detection of culture-induced suppressor activity was delayed for 5-6 weeks in C.D2 and B10.A.Bcgr mice infected intravenously with 10(4) Myco. lepraemurium bacilli. However, despite the retardation in the detection of suppressor cell precursors, the level of in vitro induced suppressor activity at onset in spleen cell suspensions of mice carrying the resistant allele was higher than in cell cultures derived from susceptible mice. As the resistant allele has a different effect when found on BALB/c or DBA/2 background, other genetic factors are apparently involved in the development of suppressor cell precursors. We finally observed that, in spleen cell cultures from intravenously infected Ity/Lsh/Bcg congenic mice on the BALB/c background, adherent and non-adherent cells were required in the inductive phase of suppressor cell development, whereas in vitro induced suppressor activity was found exclusively in the adherent cell fraction. Given these properties, we thus conclude that suppressor cell precursors detected in the spleen of these intravenously infected mice are similar to those previously observed in C3H mice infected intraperitoneally with a thousand times more bacilli.

Phenotypic characterization of two cell populations involved in the acquisition of suppressor activity by cultured spleen cells from Mycobacterium lepraemurium-infected mice.

The impairment of cellular immunity in mice infected with Mycobacterium lepraemurium was shown to correlate with the development of suppressor cells. We have previously reported that before suppressor activity is detectable in freshly harvested cell suspensions, suppressor cell precursors accumulate in the spleen of infected mice. Upon overnight culture in the presence of a regulatory cell subset, these precursor cells acquire the capacity to impair the concanavalin A (Con A)-induced proliferation of normal spleen cells. The purpose of this study was to determine the phenotype of the cells involved in this phenomenon. This was done by following the development of suppressor activity in spleen cell suspensions depleted of defined cell subsets of the adherent or the non-adherent cell fractions with selected MoAbs and immunomagnetic beads or by in vivo treatment. Our results indicate that the acquisition of suppressor activity requires the interaction of Ia+CD11b+Fc gamma R+IgG- asialo GM1- adherent cells with Thy1-CD4-CD8-IgG-Ia- asialo GM1-Fc gamma R+CD11b+ non-adherent cells. It is also shown that the development of suppressor activity is impaired by preventing cell-cell contact between these two cell subsets through coculture in 'Transwell chambers'. These observations support the conclusion that the in vitro acquisition of suppressor activity is a consequence of the maturation of suppressor cell precursors of the monocytic lineage induced by a receptor-ligand type interaction with a non-adherent cell subset that is clearly distinct from mature T, B and natural killer (NK) cells.

Lymphokine-activated killer cell function of peripheral blood mononuclear cells, spleen cells and regional lymph node cells in gastric cancer patients.

Lymphokine-activated killer (LAK) cells generated by culture of peripheral blood mononuclear cells (PBMC), spleen cells (SPC) and regional lymph node cells (LNC) with IL-2 for 4 days were examined for their functional capabilities in 29 patients with gastric carcinoma. The cytotoxic activity of LAK cells induced from LNC was significantly lower than that from either PBMC or SPC, although there was no difference between PBMC or SPC. The induction of mRNA of interferon-gamma (IFN-gamma) or tumour necrosis factor-alpha (TNF-alpha) and the production of these cytokines in the non-adherent LAK cells from LNC were also significantly reduced compared with those from PBMC or SPC. Further, the LAK cells from LNC secreted significantly lower levels of these cytokines when stimulated with tumour target, Raji cells, although the production of these cytokines was markedly increased by stimulation with the targets in all three cell populations. Phenotypic analysis of each cell population revealed a decreased proportion of the cells mediating natural killer (NK) activity, including CD16+, CD56+, and CD57+ cells in LNC either before or after culture, although OKIa1+ and CD25+ cells were uniformly increased in all cell populations after culture. Changes in subpopulations of CD4+ and CD8+ cells in LNC were not apparently different from PBMC or SPC. These results indicated the differential reactivity of each lymphocyte population to IL-2 and the reduced LAK cell function of LNC compared with PBMC or SPC in patients with gastric carcinoma.

Whole-genome transcriptional profiles of a novel marine fish iridovirus, Singapore grouper iridovirus (SGIV) in virus-infected grouper spleen cell cultures and in orange-spotted grouper, Epinephulus coioides

A DNA microarray containing all Singapore grouper iridovirus (SGIV) open reading frames (ORFs) was constructed to map the viral gene transcriptional profiles in virus-infected grouper spleen (GS) cells and in spleen tissues of virus-infected grouper. The results showed that viral genes started to be transcribed as early as 1 h postinfection (p.i.), and followed by a rapid increasing gene expression along with virus infection in cell cultures. The three temporal kinetic classes (15 immediate-early, 89 early and 53 late transcripts) were classified during an in vitro infection by their dependence on de novo protein synthesis and viral DNA replication inhibitors. In SGIV-infected grouper, Epinephulus coioides, most of the viral genes were expressed between 1 and 4 d p.i., and the number and expression levels started to decrease after 5 d p.i. These data were confirmed by real-time RT-PCR. This study provides an experimental basis for investigation of virus–host interactions and the development of control strategies against SGIV infection.

Stimulating effect of catechin, an active component of Spatholobus suberectus Dunn, on bioactivity of hematopoietic growth factor

Hematopoietic growth factor (HGF) is indispensable to hematopoiesis in the body. The proliferation and differentiation of hematopoietic cells must rely on the existence and stimulation of HGF. This study investigated the effect of catechin, an active component extracted from Spatholobus suberectus Dunn (SSD), on bioactivity of granulocyte-macrophage colony-stimulating activity (GM-CSA), burst-promoting activity (BPA) and megakaryocyte colony-stimulating activity (MK-CSA) in spleen condition medium (SPCM) of mice to clarify the hematopoietic mechanism of catechin and SSD. Spleen cells of mice were separated and spleen condition medium (SPCM) was prepared from spleen cell culture. Bone marrow cells of mice were separated and cultured in a culture system including 10% (v/v) SPCM (induced by catechin in vivo or ex vivo) for 6 days. Granulocyte-macrophage colony forming units (CFU-GM), erythrocyte burst-colony-forming units (BFU-E) and megakaryocyte colony-forming units (CFU-Meg) formation were employed to assay the effects of different treatment on the bioactivity of GM-CSA, BPA and MK-CSA in SPCM. SPCM induced by 100 mg/L catechin ex vivo could promote the growth of CFU-GM, BFU-E and CFU-Meg, which indicated that catechin could stimulate the production of GM-CSA, BPA and MK-CSA in SPCM. SPCM prepared at the fourth day of spleen cell culture showed the best stimulating activity. The bioactivity of GM-CSA, BPA and MK-CSA in the SPCM prepared after intraperitoneally injecting catechin into mice was also increased. The number of CFU-GM, BFU-E and CFU-Meg gradually increased as the dose of catechin increased and the time of administration prolonged. CFU-GM, BFU-E and CFU-Meg of the high-dose catechin group were significantly higher than those of the control group (P < 0.01) and reached the maximum at the seventh day after administration. This study suggests that catechin extracted from the active acetic ether part of Spatholobus suberectus Dunn can regulate hematopoiesis by inducing bioactivity of GM-CSA, BPA and MK-CSA in SPCM of mice. This may be one of the mechanisms for the hematopoietic-supportive effect of catechin and Spatholobus suberectus Dunn.

Immune Response to Nocardia brasiliensis Extracellular Antigens in Patients with Mycetoma

The ability of culture-filtrate proteins to induce a cellular immune response in infected mice and humans was investigated. A crude extract culture filtrate of Nocardia brasiliensis (CFA) and five semi-purified CFA fractions (P1, P2, P3, P4, P5) were used to stimulate BALB/c mice spleen-cell cultures. The animals were divided into three groups: the first group was infected with 1 x 10(7) CFU of N. brasiliensis in the footpad, the second group was immunized with heat-killed bacteria, and the third was injected with sterile saline. IFN-gamma, IL-1alpha, and IL-4 concentrations were determined in culture supernatants. Protein fractions eliciting IFN-gamma production in mice, as well as the CFA, were used to stimulate IFN-gamma production and in vitro cell proliferation assays with peripheral blood mononuclear cells of patients with actinomycetoma by N. brasiliensis, individuals with pulmonary tuberculosis, and healthy controls. In mice, CFA and three of the protein fractions (P3, P4 and P5) induced significant IFN-gamma production in the infected group. In humans, only the CFA-induced IFN-gamma production and cell proliferation in the group of patients with actinomycetoma. There was no stimulation in tuberculosis patients nor healthy controls. These results suggest that some culture-filtrate antigens are recognized by patients with active actinomycetoma and do not cross-react with M. tuberculosis antigens, being therefore potential candidates to develop a diagnostic test.

Intranasal vaccination with poly(lactide‐co‐glycolide) microparticles containing a peptide T of Ole e 1 prevents mice against sensitization

Biodegradable microparticles, in particular poly(lactide-co-glycolide) (PLGA), have been shown as potential delivery vehicles for intranasal (i.n.) vaccines in animal models. To evaluate whether i.n. administration of PLGA microparticles containing a peptide with the major T cell epitope of Ole e 1, the main allergen of olive pollen, prevented mice from allergic sensitization to the whole protein. Peptide-PLGA microparticles were prepared by a solvent evaporation double emulsion method. Microparticles in a size range of 0.8 mum were evaluated for peptide loading and in vitro antigen release. Stability and immunogenicity of the entrapped peptide were retained, as determined by dot blot and ELISA inhibition. BALB/c mice were intranasally treated with peptide-PLGA microparticles for 3 consecutive days, 1 week before sensitization/challenge to Ole e 1. Blood, lungs and spleen were collected and analysed for immune response. Biodistribution of microparticles was investigated using confocal microscopy. I.n. pretreatment of BALB/c mice with peptide-PLGA microparticles before sensitization to Ole e 1 led to a significant inhibition of serum allergen-specific IgE and IgG1 antibody levels, but a marked increase of specific IgG2a antibodies as compared with sham-pretreated mice. Moreover, IL-5 and IL-10 levels in spleen cell cultures were suppressed in peptide-PLGA pretreated mice. The airway histopathologic parameters associated with inflammation were significantly suppressed by the pretreatment. These results demonstrate that i.n. immunization with peptide T-PLGA microparticles is effective in preventing subsequent allergic sensitization to Ole e 1. Our data indicate that peptide-PLGA microparticles may be promising candidates for the design of nasal vaccines against allergic diseases in humans.

Feeding a Diet Containing a Fructooligosaccharide Mix Can Enhance Salmonella Vaccine Efficacy in Mice

Fructooligosaccharides (FOS) are considered prebiotics because of their ability to promote growth of specific beneficial gut bacteria, such as bifidobacteria. Some studies reported potential immune-modulating properties. The aim of this study was to investigate the effect of FOS:inulin mix on murine response to Salmonella vaccine and evaluate the relevance toward protection against Salmonella infection. Balb/c mice were fed a diet containing 5% FOS:inulin mix or a control diet 1 wk before oral immunization with a suboptimal dose of live attenuated Salmonella typhimurium vaccine. Four weeks after vaccination, mice were infected with LD100 of virulent S. typhimurium. Specific blood Salmonella immunoglobulin G and fecal immunoglobulin A significantly increased in mice fed the diet containing prebiotics compared with control mice 4 wk postimmunization. Peritoneal macrophage phagocytic activity also significantly increased in FOS:inulin-fed mice at 1 wk postimmunization compared with control mice. No detectable effects were observed on the percentage of lymphoid cell subsets in the spleen. However, production of cytokines, interferon-γ, interleukin-12, and tumor necrosis factor α, was numerically increased in spleen cell cultures stimulated with mitogens from FOS:inulin-fed mice 1 and 4 wk postimmunization. Salmonella translocation to lymphoid organs was not affected by feeding FOS:inulin. However, the improved response to Salmonella vaccine was concomitant with an increase in the survival rate of FOS:inulin-fed mice upon challenge with virulent Salmonella. No detectable effects were observed on the composition or the metabolic activity of the microbiota. Overall, the data suggest that a diet supplemented with FOS:inulin mix stimulates mucosal immunity and seems to improve efficacy of an oral vaccine.

Warifteine, a bisbenzylisoquinoline alkaloid, decreases immediate allergic and thermal hyperalgesic reactions in sensitized animals

Warifteine is a bisbenzylisoquinoline alkaloid isolated from the Cissampelos sympodialis Eichl (Menispermaceae). This plant is used in the folk medicine for the treatment of airway respiratory diseases. A murine model of immediate allergic reaction was used to evaluate warifteine treatment in the IgE production, leukocyte activation, thermal hyperalgesia, mast cell degranulation and scratching behavior. BALB/c mice treated with warifteine (0.4–10 mg/Kg) 1 h before OVA sensitization reduced OVA induced paw edema as well as the OVA-specific IgE serum titers as compared with non-treated and OVA-sensitized animals. Warifteine also reduced the mice death evoked by IgE-dependent anaphylactic shock reaction at 30 min after intravenous OVA challenge. To assess the effect of warifteine treatment on T cell proliferative response, spleen cells from warifteine treated or non-treated and OVA-sensitized animals were evaluated. Spleen cells from warifteine treated animals (2.0 mg/kg) did not proliferate following OVA stimulation as compared with spleen cell cultures from non-treated animals. This response may be related with the increase of NO production as observed in peritoneal macrophage cultures treated with warifteine. Thermal hyperalgesia evoked by IgE or histamine/5-hydroxytryptamine challenge was inhibited on rats at dose of 4.0 mg/kg. Warifteine treatment (0.6 or 6.0 µg/ml) also decreased the IgEαDNP-BSA sensitized mast degranulation after DNP-BSA challenge measured by histamine release. In addition, compound 48/80-induced scratching behavior was also sensitive to warifteine treatment. These results demonstrate for the first time that warifteine treatment reduced the allergy-associated responses.

Selective silencing of DNA‐specific B lymphocytes delays lupus activity in MRL/lpr mice

The pathological DNA-specific B lymphocytes in lupus are logical targets for a selected therapeutic intervention. We have hypothesized that it should be possible to suppress selectively the activity of these B cells in lupus mice by administering to them an artificial molecule that cross-links their surface immunoglobulins with the inhibitory FcgammaIIb surface receptors. A hybrid molecule was constructed by coupling the DNA-mimicking DWEYSVWLSN peptide to a monoclonal anti-mouse FcgammaRIIb antibody. This chimeric antibody was added to cultured spleen cells from sick MRL/lpr mice, immunized with diphtheria toxoid, resulting in reduction of the numbers of anti-DNA but not of anti-diphtheria IgG antibody-producing cells. Intravenous infusions with the DNA-peptide antibody chimera to 7-wk-old animals prevented the appearance of IgG anti-DNA antibodies and of albuminuria in the next 2 months. The administration of the DNA-peptide chimeric antibody to 18 wk-old mice with full-blown disease resulted in the maintenance of a flat level of IgG anti-DNA antibodies and in delay of the aggravation of the lupus glomerulonephritis. The use of chimeric antibodies targeting inhibitory B lymphocyte receptors represents a novel approach for the selective suppression of autoreactive disease-associated B cells in autoimmune diseases.

Adjuvant activities of saponins from the root of Polygala senega L.This article is one of a selection of papers published in this special issue (part 2 of 2) on the Safety and Efficacy of Natural Health Products.

Eight pure triterpenoid saponin compounds isolated from the root of Polygala senega L., a plant indigenous to the Canadian prairies, were evaluated for their immunological activity in mouse models. The specific antibody responses of the IgG2a subclass increased significantly when isolated P. senega saponins were used as adjuvants in the immunization of mice with OVA antigen. In addition, increased IL-2 levels were observed in spleen cell cultures from P. senega saponin-immunized mice after in vitro secondary antigen stimulation. The saponins were tested for their toxicity in mice by using a haemolytic activity assay and found to be less toxic than Quillaja saponaria saponins that have long been used as adjuvants in vaccine formulations. This study has shown the potential of P. senega saponins to be considered as a natural source of vaccine adjuvants with biological activity equivalent to the current commercially available saponin adjuvants.