Electroacupuncture preconditioning attenuates acute myocardial ischemia injury through inhibiting NLRP3 inflammasome activation in mice.

AIMS: Electro-acupuncture pretreatment (EAP) plays a protective role in myocardial ischemia (MI) injury. However, the underlying mechanism remains unclear. A growing body of evidence suggests postinfarction inflammatory response directly affects the remodeling of ventricular function. The purpose of this study was to investigate whether EAP alleviates MI through NLRP3 inflammasome inhibition. MATERIALS AND METHODS: We constructed an AMI model by ligating the left anterior descending (LAD) coronary artery after 3 days of EAP with C57BL/6 mice. Echocardiography and TTC staining were employed to evaluate cardiac function and infarct size after 24 h of ischemia. HE staining and immunohistochemistry were employed to determine inflammatory level. Then, inflammasome activation was detected by western blotting, and macrophage polarization and neutrophil infiltration were observed by flow cytometry. KEY FINDINGS: Our preliminary findings showed that EAP reduced the infarct area and increased fractional shortening (FS) and ejection fraction (EF) and decreased the degree of inflammation after AMI injury. Meanwhile, EAP inhibited the expression of NLRP3, cleaved caspase-1 and IL-1ß in ischemia myocardial tissue, companied by inhibiting the expression of F4/80+, CD11b+, CD206low macrophages and activated M2 macrophage, and decreasing Ly-6G+CD11b+ neutrophils in ischemia myocardial and spleen tissue. SIGNIFICANCE: EAP inhibits the activation of NLRP3 inflammasome, promotes M2 polarization of macrophages and reduces the recruitment of neutrophils in damaged myocardium, thereby decreases the infarct size and improves the cardiac function.

Effects of myeloid cell-restricted TNF inhibitors in vitro and in vivo.

Systemic TNF neutralization can be used as a therapy for several autoimmune diseases. To evaluate the effects of cell type-restricted TNF blockade, we previously generated bispecific antibodies that can limit TNF secretion by myeloid cells (myeloid cell-specific TNF inhibitors or MYSTIs). In this study several such variable domain (VH) of a camelid heavy-chain only antibody-based TNF inhibitors were compared in relevant experimental models, both in vitro and in vivo. Pretreatment with MYSTI-2, containing the anti-F4/80 module, can restrict the release of human TNF (hTNF) from LPS-activated bone marrow-derived macrophage (BMDM) cultures of humanized TNF knock-in (mice; hTNFKI) more effectively than MYSTI-3, containing the anti-CD11b module. MYSTI-2 was also superior to MYSTI-3 in providing in vivo protection in acute toxicity model. Finally, MYSTI-2 was at least as effective as Infliximab in preventing collagen antibody-induced arthritis. This study demonstrates that a 33 kDa bispecific mini-antibody that specifically restricts TNF secretion by macrophages is efficient for amelioration of experimental arthritis.

miR-130a and miR-145 reprogram Gr-1+CD11b+ myeloid cells and inhibit tumor metastasis through improved host immunity.

Tumor-derived soluble factors promote the production of Gr-1+CD11b+ immature myeloid cells, and TGFß signaling is critical in their immune suppressive function. Here, we report that miR-130a and miR-145 directly target TGFß receptor II (TßRII) and are down-regulated in these myeloid cells, leading to increased TßRII. Ectopic expression of miR-130a and miR-145 in the myeloid cells decreased tumor metastasis. This is mediated through a downregulation of type 2 cytokines in myeloid cells and an increase in IFNγ-producing cytotoxic CD8 T lymphocytes. miR-130a- and miR-145-targeted molecular networks including TGFß and IGF1R pathways were correlated with higher tumor stages in cancer patients. Lastly, miR-130a and miR-145 mimics, as well as IGF1R inhibitor NT157 improved anti-tumor immunity and inhibited metastasis in preclinical mouse models. These results demonstrated that miR-130a and miR-145 can reprogram tumor-associated myeloid cells by altering the cytokine milieu and metastatic microenvironment, thus enhancing host antitumor immunity.

Mesenteric lymph node CD11b- CD103+ PD-L1High dendritic cells highly induce regulatory T cells.

Dendritic cells (DCs) in mesenteric lymph nodes (MLNs) induce Foxp3+ regulatory T cells to regulate immune responses to beneficial or non-harmful agents in the intestine, such as commensal bacteria and foods. Several studies in MLN DCs have revealed that the CD103+ DC subset highly induces regulatory T cells, and another study has reported that MLN DCs from programmed death ligand 1 (PD-L1) -deficient mice could not induce regulatory T cells. Hence, the present study investigated the expression of these molecules on MLN CD11c+ cells. Four distinct subsets expressing CD103 and/or PD-L1 were identified, namely CD11b+ CD103+ PD-L1High , CD11b- CD103+ PD-L1High , CD11b- CD103+ PD-L1Low and CD11b+ CD103- PD-L1Int . Among them, the CD11b- CD103+ PD-L1High DC subset highly induced Foxp3+ T cells. This subset expressed Aldh1a2 and Itgb8 genes, which are involved in retinoic acid metabolism and transforming growth factor-ß (TGF-ß) activation, respectively. Exogenous TGF-ß supplementation equalized the level of Foxp3+ T-cell induction by the four subsets whereas retinoic acid did not, which suggests that high ability to activate TGF-ß is determinant for the high Foxp3+ T-cell induction by CD11b- CD103+ PD-L1High DC subset. Finally, this subset exhibited a migratory DC phenotype and could take up and present orally administered antigens. Collectively, the MLN CD11b- CD103+ PD-L1High DC subset probably takes up luminal antigens in the intestine, migrates to MLNs, and highly induces regulatory T cells through TGF-ß activation.

α-Tocopherol supplementation of allergic female mice inhibits development of CD11c+CD11b+ dendritic cells in utero and allergic inflammation in neonates.

α-Tocopherol blocks responses to allergen challenge in allergic adult mice, but it is not known whether α-tocopherol regulates the development of allergic disease. Development of allergic disease often occurs early in life. In clinical studies and animal models, offspring of allergic mothers have increased responsiveness to allergen challenge. Therefore, we determined whether α-tocopherol blocked development of allergic responses in offspring of allergic female mice. Allergic female mice were supplemented with α-tocopherol starting at mating. The pups from allergic mothers developed allergic lung responses, whereas pups from saline-treated mothers did not respond to the allergen challenge, and α-tocopherol supplementation of allergic female mice resulted in a dose-dependent reduction in eosinophils in the pup bronchoalveolar lavage and lungs after allergen challenge. There was also a reduction in pup lung CD11b(+) dendritic cell subsets that are critical to development of allergic responses, but there was no change in several CD11b(-) dendritic cell subsets. Furthermore, maternal supplementation with α-tocopherol reduced the number of fetal liver CD11b(+) dendritic cells in utero. In the pups, there was reduced allergen-induced lung mRNA expression of IL-4, IL-33, TSLP, CCL11, and CCL24. Cross-fostering pups at the time of birth demonstrated that α-tocopherol had a regulatory function in utero. In conclusion, maternal supplementation with α-tocopherol reduced fetal development of subsets of dendritic cells that are critical for allergic responses and reduced development of allergic responses in pups from allergic mothers. These results have implications for supplementation of allergic mothers with α-tocopherol.

Antigen targeting to CD11b+ dendritic cells in association with TLR4/TRIF signaling promotes strong CD8+ T cell responses.

Deciphering the mechanisms that allow the induction of strong immune responses is crucial to developing efficient vaccines against infectious diseases and cancer. Based on the discovery that the adenylate cyclase from Bordetella pertussis binds to the CD11b/CD18 integrin, we developed a highly efficient detoxified adenylate cyclase-based vector (CyaA) capable of delivering a large variety of Ags to the APC. This vector allows the induction of protective and therapeutic immunity against viral and tumoral challenges as well as against transplanted tumors in the absence of any added adjuvant. Two therapeutic vaccine candidates against human papilloma viruses and melanoma have been developed recently, based on the CyaA vector, and are currently in clinical trials. We took advantage of one of these highly purified vaccines, produced under good manufacturing practice-like conditions, to decipher the mechanisms by which CyaA induces immune responses. In this study, we demonstrate that CyaA binds both human and mouse CD11b(+) dendritic cells (DCs) and induces their maturation, as shown by the upregulation of costimulatory and MHC molecules and the production of proinflammatory cytokines. Importantly, we show that DCs sense CyaA through the TLR4/Toll/IL-1R domain-containing adapter-inducing IFN-ß pathway, independent of the presence of LPS. These findings show that CyaA possesses the intrinsic ability to not only target DCs but also to activate them, leading to the induction of strong immune responses. Overall, this study demonstrates that Ag delivery to CD11b(+) DCs in association with TLR4/Toll/IL-1R domain-containing adapter-inducing IFN-ß activation is an efficient strategy to promote strong specific CD8(+) T cell responses.

Different peripheral tissue injury induces differential phenotypic changes of spinal activated microglia.

The purpose of this study is to investigate the possible different cellular marker expression associated with spinal cord microglial activation in different pain models. Immunohistochemistry and western blotting analysis of CD45, CD68, and MHC class I antigen as well as CD11b and Iba-1 in the spinal cord were quantitatively compared among widely used three pain animal models, complete Freund's adjuvant (CFA) injection, formalin injection, and chronic constriction injury (CCI) models. The results showed that significant upregulated expressions of CD45 and MHC class I antigen in spinal microglia as well as morphological changes with increased staining with CD11b and Iba-1 were seen in CCI and formalin models and not found in CFA-induced inflammatory pain model. CD68 expression was only detected in CCI model. Our findings suggested that different peripheral tissue injuries produced differential phenotypic changes associated with spinal microglial activation; peripheral nerve injury might induce spinal microglia to acquire these immunomolecular phenotypic changes.

Arginase-dependent suppression by CpG-ODN plus IFA-induced splenic myeloid CD11b(+)Gr1(+) cells.

The ability of synthetic oligodeoxynucleotides containing unmethylated cytosine guanine motifs (CpG-ODN) to induce both stimulatory and counter-regulatory responses offers novel opportunities for using these molecules as immunomodulatory agents in different therapeutic strategies. Here, we investigated the potential of CpG-ODN to activate the arginase (ARG) enzyme in vivo and focused on the consequences of this activation in T-cell proliferation. Challenging mice subcutaneously with CpG-ODN emulsified in incomplete Freund's adjuvant (IFA) induced ARG and reduced T-cell proliferation associated with CD3ζ chain downregulation. Interestingly, impaired T-cell expansion correlated with elevated levels of CD11b(+)Gr1(+) myeloid cells localized near T-cell areas in the spleen. In addition, purified CD11b(+) cells obtained from the spleen of CpG-ODN+IFA-treated mice exhibited increased ARG activity and ARG I expression along with an augmented [(3)H]-L-arginine uptake. CD11b(+) myeloid cells significantly suppressed T-cell proliferation and CD3ζ chain expression induced by a polyclonal stimulus. Furthermore, these effects could be recovered by the addition of excess L-arginine or by treatment of CD11b(+) cells with a specific ARG inhibitor. This study provides a novel evidence that CpG-ODN+IFA are able to induce splenic CD11b(+) cells with ARG activity, with this population being responsible for the impaired T-cell proliferation observed after the treatment with CpG-ODN+IFA. These results underscore a key role of CpG-ODN on ARG activity in vivo and add support to the growing body of evidence in favor of a counter-regulatory role for CpG-ODN in an immune response.

Spontaneous and aging-dependent development of arthritis in NADPH oxidase 2 deficiency through altered differentiation of CD11b+ and Th/Treg cells.

Emerging evidence indicates that NADPH oxidase (NOX) and its reactive oxygen species (ROS) products modulate a variety of cellular events, including proliferation, differentiation, and apoptosis. In this study, we investigated the functions of NOX2 and ROS in immune modulation using NOX2 knockout (KO) mice. Interestingly, NOX2 KO mice spontaneously developed arthritis with onset at 6-7 wk of age and high incidence (60%) at 15-18 wk of age. Arthritis severity in NOX2 KO mice was proportionally increased with age and higher in females than in males. Bone destruction was confirmed by microcomputed tomography scanning and histological analyses of joints. Inflammatory factors, including TNF-α, IL-1ß, and RANKL, and serum level of anti-type II collagen IgG were significantly increased in NOX2 KO mice. In addition, NOX2 deficiency perturbed the immune system upon aging. NOX2 KO mice demonstrated preferred development of CD11b+Gr-1+ myeloid cells with profound production of proinflammatory cytokines and augmented expression of IL-17 through the activation of STAT3 and RORγt in vivo. NOX2 deficiency increased differentiation of effector Th cells in vitro and decreased CD25+FoxP3+ Treg cells both in vitro and in vivo. Furthermore, adoptive transfer of NOX2-deficient CD4(+) T cells into RAG KO mice increased arthritic inflammation compared with WT cells. These results demonstrated that NOX2 deficiency affected the development of CD11b+ myeloid cells and Th17/Treg cells, and thus promoted inflammatory cytokine production and inflammatory arthritis development, strongly supporting a crucial role for ROS generation in the modulation of Th17/Treg cell development and its related inflammatory immune response upon aging.

The role of intestinal dendritic cells subsets in the establishment of food allergy.

BACKGROUND: Food allergy affects approximately 6% of children and is the leading cause of hospitalization for anaphylactic reactions in westernized countries. Crucial in the establishment of allergy is the activation of dendritic cells (DC) leading to T helper 2-mediated responses. OBJECTIVE: We, therefore, investigated whether changes in DC subsets precede the establishment of food allergy, and which DC subsets have functional relevance during allergic sensitization in a mouse model. METHODS: Changes in DC populations in the intestine were analysed after exposure to cholera toxin alone and in combination with peanut extract (PE) as an allergen. To study the functional role of DC subsets in relation to food allergy, we used expansion of DC in vivo by treatment with Flt3L. RESULTS: Sensitization to PE in this mouse model was accompanied by a shift in DC subsets in intestinal tissues towards more CD11b(+) DC and less CD103(+) DC. No significant changes in the plasmacytoid DC (pDC) numbers were observed. Flt3L treatment, resulting in the expansion of all DC subtypes, inhibited allergic manifestations in our model, including Th2 cytokine production, PE-specific IgE and PE-induced mast cell degranulation. pDC depletion reversed Flt3L-induced inhibition of IgE responses and mast cell degranulation. conclusions and clinical relevance: The establishment of food allergy is accompanied by profound changes in DC subsets in the intestine towards more inflammatory CD11b(+) DC. In addition, expansion of DC numbers by Flt3L, in particular pDC, inhibits the establishment of allergic manifestations in the intestine. These findings are of relevance for understanding the role of DC subsets early during the process of allergic sensitization, and may lead to new therapeutic or prophylactic opportunities to prevent food allergy.

Areca nut extracts enhance the development of CD11b(+) Gr-1(+) cells with the characteristics of myeloid-derived suppressor cells in antigen-stimulated mice.

BACKGROUND: Areca quid chewing is an etiological factor contributing to the development of oral cancer and pre-cancers, whose pathophysiology has been linked to inflammation and immune deterioration. Myeloid-derived suppressor cells (MDSC) play a key role in the regulation of immunity under certain pathological conditions, such as inflammation and cancer. As areca nut extracts (ANE) have been reported to induce a proinflammatory effect in antigen-stimulated mice, we hypothesized that ANE might enhance the development of MDSC. METHODS: Ovalbumin (OVA)-sensitized BALB/c mice were daily administered with ANE (5-50 mg/kg), polyphenol-enriched ANE (PANE; 25 mg/kg) or arecoline (5 mg/kg) by intraperitoneal injection for 10 doses. The mouse footpads were then subcutaneously challenged with OVA to induce local inflammatory responses. RESULTS: ANE and PANE treatment significantly increased the spleen index and the population of CD11b(+) Gr-1(+) cells in the spleen and peripheral blood, whereas arecoline was inactive. In addition, ANE and PANE treatment enhanced the expression of cytokines and enzymes associated with the immunosuppressive function of MDSC, including IL-10, arginase-I and iNOS in splenic CD11b(+) cells. Concordantly, ANE and PANE treatment augmented the infiltration of Gr-1(+) IL-10(+) cells in the footpads challenged with OVA. CONCLUSIONS: Our results suggested that areca nut constituents, in particular, polyphenols enhanced the development of myeloid-derived suppressor cells in vivo, which may be a critical mechanism linking inflammation and the compromised immunity reported to be associated with the pathophysiology of areca-related oral diseases.

Catechin inhibits adhesion and migration of peripheral blood B cells by blocking CD11b.

CONTEXT: Previously, we demonstrated that CD11b is expressed on peripheral blood memory B cells, and it plays an important role in the migration of B cells. And epigallocatechin gallate (EGCG), a bioactive component of green tea, by binding to CD11b, expressed on CD8(+) cytotoxic T cells, inhibited their migratory ability, one possible mechanism of the antiallergic activity of EGCG. OBJECTIVE: Here, we investigated whether EGCG also affected CD11b expressed on B cells, similar to cytotoxic T cells. MATERIALS AND METHODS: Isolated peripheral blood CD19(+) B cells were treated with EGCG and the change in the expression of CD11b was analyzed using flow cytometry. The effects of EGCG on the ability of B cells to adhere to and to transmigrate through the endothelial cell layer were evaluated using the transwell assay. RESULTS: EGCG significantly suppressed the apparent expression of CD11b on B cells, in the flow-cytometric analysis, and this apparent suppression was speculated to be dependent on the competitive binding of EGCG to CD11b. EGCG also significantly suppressed CD11b-mediated migration and adhesion of B cells to endothelial cells. DISCUSSION AND CONCLUSION: EGCG has a strong suppressive activity on the adhesive and migratory abilities of peripheral blood B cells. This suppressive activity was mediated by the binding of EGCG to CD11b on B cells, and the consequent suppression of B-cell extravasation to the extravascular space. Because B cell plays an important role in the humoral immunity, EGCG could be a promising drug for the prevention and/or treatment of allergic and/or autoimmune diseases.

Participation of CD11b and F4/80 molecules in the conjunctival eosinophilia of experimental allergic conjunctivitis.

BACKGROUND: CD11b and F4/80 are macrophage surface markers. How these molecules participate in allergic eosinophil infiltration remains unclear. We examined the roles CD11b and F4/80 play in the conjunctival eosinophil infiltration associated with experimental allergic conjunctivitis. METHODS: Ragweed-immunized BALB/c mice were challenged with ragweed in eye drops to induce conjunctival eosinophil infiltration. The effect of challenge on conjunctival CD11b+ and F4/80+ cell numbers was determined by immunohistochemistry. In the same model, blocking anti-CD11b and anti-F4/80 Abs were injected intraperitoneally during the induction or the effector phase, or subconjunctivally 2 h before challenge, to determine their effect on challenge-induced conjunctival eosinophilia. To examine whether eosinophils express CD11b and F4/80 molecules, splenocytes from IL-5 gene-electroporated mice were subjected to flow cytometric analysis. To clarify the involvement of CD11b and F4/80 in conjunctival eosinophil infiltration, mice were intraperitoneally injected with anti-CD11b and anti-F4/80 Abs and then subconjunctivally injected with eotaxin to induce conjunctival eosinophilia. RESULTS: Ragweed challenge elevated conjunctival CD11b+ and F4/80+ cell numbers. Systemic anti-CD11b and anti-F4/80 Ab treatments during the effector phase, but not in either the induction phase or the local injection of Ab, suppressed conjunctival eosinophil infiltration in ragweed-induced conjunctivitis. Most splenic eosinophils from IL-5 gene-introduced mice expressed CD11b and F4/80. Systemic anti-CD11b and anti-F4/80 Ab treatment suppressed conjunctival eosinophilia induced by subconjunctival eotaxin injection. CONCLUSIONS: CD11b and F4/80 appear to participate in conjunctival eosinophil infiltration in allergic conjunctivitis. Their involvement in conjunctival eosinophilia appears to be due to their expression on eosinophils rather than on macrophages.

Effects of parenteral glutamine supplementation on modulating the immune response in rats undergoing a total gastrectomy.

The present study investigated the effect of parenteral glutamine (Gln) supplementation on cellular adhesion molecule expression and release of chemokines responsible for inflammatory cell recruitment in rats undergoing a total gastrectomy. Normal rats with internal jugular catheters were assigned to one control group and two experimental groups and received total parenteral nutrition (TPN). A total gastrectomy was performed in the experimental groups, whereas the control group received a sham operation (Sham). The TPN solutions were isonitrogenous and identical in nutrient composition except that the Sham group and one of the experimental group received conventional (Conv) TPN solution, whereas the other experimental group received 25% of the amino acid nitrogen as Gln. Half of the rats in each group were killed 1 or 3 d after surgery or the Sham to examine their immune response. The results showed that the surgery produced higher polymorphonuclear leucocyte CD11b/CD18 expressions, and Gln supplementation lowered CD11b/CD18 expressions compared with the Conv group post-operatively. The levels of monocyte chemotactic protein-1 and macrophage inflammatory protein-2 in peritoneal lavage fluid were higher in the Gln group than those in the Conv group 1 d post-operatively; these chemotactic proteins had returned to the levels comparable with those in the Sham group on post-operative day 3. These results suggest that Gln supplementation attenuated polymorphonuclear leucocyte integrin expression. In addition, Gln-enriched parenteral nutrition induced an earlier more intensive and rapid immune response to injury than the Conv parenteral nutrition after a total gastrectomy.

Immunomodulatory effect of Antrodia camphorata mycelia and culture filtrate.

AIM OF THE STUDY: Antrodia camphorata, a precious folkloric medicinal mushroom, has been used to treat tumorigenic diseases in Taiwan. This study was to investigate the innate immunity augmentation effects of different fractions prepared from hot water extracts of submerged cultured Antrodia camphorata (AC). MATERIALS AND METHODS: The cytokine induction potency of AC fraction in diluted peripheral blood culture was measured by ELISA. The effects of AC fraction on phagocytic activity and CD11b expression were measured by the ingestion of FITC-labeled Escherichia coli and by labeling with PE-labeled CD11b monoclonal antibody, respectively, using flow cytometry. The molecular mass of hot water-soluble polysaccharides and content of adenosine in AC fraction were determined by gel permeation chromatography (GPC) and HPLC, respectively. RESULTS: The mycelia fraction, Fr. M II, and culture filtrate fractions, Fr. E II and Fr. E III, showed the strongest TNF-alpha and IL-6 induction effect as a function of their concentration. These fractions (20mug/ml) also showed marked activity in enhancing phagocytosis in human polymorphonuclear neutrophils (PMN) and monocytes. In parallel, the expression of CD11b, an early marker of PMN activation, was also up-regulated dose-dependently. Composition analysis suggested that immunomodulatory effect of mycelia is mainly attributed to the 10-20kDa polysaccharides and adenosine. CONCLUSIONS: These results provide evidences that Antrodia camphorata can modulate innate immunity and may serve as an adjuvant for tumor treatment.

Immunomodulatory effect of exo-polysaccharides from submerged cultured Cordyceps sinensis: enhancement of cytokine synthesis, CD11b expression, and phagocytosis.

Cordyceps sinensis is widely used as a traditional medicine for treatment of a wide variety of diseases or to maintain health. The immunomodulatory activity of polysaccharides prepared from submerged cultured C. sinensis BCRC36421 was investigated in human peripheral blood. Results demonstrated that Fr. A (exo-polysaccharides, 0.025 approximately 0.1 mg/ml) induced the production of tumor necrosis factor alpha (TNF-alpha), interleukin (IL)-6, and IL-10 dose-dependently. Fr. A, as low as 0.025 mg/ml, could significantly augment surface expression of CD11b in monocytes and polymorphonuclear neutrophils. Functional assay revealed that Fr. A (0.05 mg/ml) also elevated phagocytosis in monocytes and PMN. On the other hand, Fr. B (intracellular polysaccharides) only moderately induced TNF-alpha release, CD11b expression, and phagocytosis at the same concentrations. Our results indicate that the immunomodulatory components of submerged cultured C. sinensis mainly reside in the culture filtrate.

Ameliorating effect of saporin-conjugated anti-CD11b monoclonal antibody in a murine T-cell-mediated chronic colitis.

BACKGROUND: Crohn's disease (CD) is an inflammatory bowel disease that is associated with several changes in the immune system, including an increased number of infiltrating macrophages. These macrophages release a variety of pro-inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha) which are critically involved in the onset and the development of CD. The present study was performed to explore the initial involvement of macrophages in the development of T-cell-mediated chronic colitis. METHODS: The effects were evaluated of saporin-conjugated anti-CD11b monoclonal antibody (mAb) on the development of chronic colitis in severe combined immunodeficiency (SCID) mice induced by adoptive transfer of CD4(+)CD45RB(high) T cells as an animal model of CD. RESULTS: Significantly increased CD11b-expressing macrophages as well as CD4(+) T cells were found in inflamed colon from colitic mice. Administration of saporin-conjugated anti-CD11b mAb markedly ameliorated the clinical and histopathological disease. In vivo treatment with saporin-conjugated anti-CD11b mAb decreased CD4(+) T-cell infiltration in the colon and suppressed interferon-gamma (IFN-gamma) and TNF-alpha production by lamina propria CD4(+) T cells. CONCLUSIONS: Collectively, the present results suggest an initial role of macrophages in the pathogenesis of T-cell-mediated chronic colitis. Furthermore, the macrophage-specific targeting may be a promising strategy for therapeutic intervention in CD.

The effect of treatment with moxifloxacin or azithromycin on acute bacterial rhinosinusitis in mice.

OBJECTIVE: Acute bacterial rhinosinusitis, which is a major health problem, is treated with antibiotics. We developed a mouse model of acute bacterial rhinosinusitis to gain a better understanding of the pathophysiology of the disease. Our goal was to investigate the response to acute rhinosinusitis when treated with either a bactericidal or a bacteriostatic antibiotic. METHODS: C57BL/6 mice were infected intranasally with Streptococcus pneumoniae. One day after inoculation, the mice were treated with either moxifloxacin (bactericidal) or azithromycin (bacteriostatic). Different groups were euthanized during the first five days post-inoculation. Bacterial counts from nasal lavage culture and the cell markers GR1, CD11b, CD3, CD4, and CD8 in sinus tissue were evaluated by flow cytometry. RESULTS: Azithromycin led to rapid clearance of the bacteria and of the inflammation in contrast to placebo. Surprisingly, moxifloxacin showed a limited effect. Investigations of this limited effect of moxifloxacin suggested a high metabolic clearance, a low concentration at the site of infection, and low persistent post-antibiotic effects of moxifloxacin in mice. CONCLUSION: Our animal model of acute sinusitis has great utility for studying the disease, but the difference between mice and man must always be considered in making extrapolations from animal experiments to the human experience.

Dietary glutamine supplementation reduces cellular adhesion molecule expression and tissue myeloperoxidase activity in mice with gut-derived sepsis.

OBJECTIVES: This study investigated the effects of glutamine (Gln) on plasma intracellular adhesion molecule-1 levels and leukocyte integrin (CD11a/CD18 and CD11b/CD18) expressions in gut-derived sepsis. Myeloperoxidase (MPO) activities in organs were also analyzed to identify the extent of tissue injury resulting from neutrophil infiltration. METHODS: Mice were randomly assigned to a normal group (NC), a control group, or a Gln group. The NC group was fed standard chow diet; the control group was fed a common semipurified diet; and the Gln group received a diet in which part of the casein was replaced by Gln, which provided 25% of total amino acid nitrogen. After 3 wk, sepsis was induced by cecal ligation and puncture (CLP) in the control and Gln groups. Mice in the experimental groups were killed at 0, 6, 12, and 24 h after CLP. Mice in the NC group were killed when CLP was performed. Blood and organ samples were collected for further analysis. RESULTS: Plasma intracellular adhesion molecule-1 levels were significantly lower in the Gln group than in the control group at 6, 12, and 24 h after CLP. Expressions of lymphocyte CD11a/CD18 were significantly higher, whereas polymorphonuclear lymphocyte expressions of CD11b/CD18 were lower in the Gln group than in the corresponding control group at 6 and 12 h after CLP. In comparisons of MPO activities in various organs, the Gln group had lower MPO activities at 6 and 12 h in the lung, at 6, 12, and 24 h in the liver, at 12 and 24 h in the kidneys, and at 12 h in the intestine than those in the control group. CONCLUSIONS: Results of this study demonstrate that a Gln-supplemented enteral diet increased lymphocyte CD11a/CD18 expressions, whereas neutrophil CD11b/CD18 expressions, circulating intracellular adhesion molecule-1 levels, and MPO activities in various organs decreased with gut-derived sepsis. These findings suggest that, under septic conditions, Gln administration may enhance lymphocyte function, attenuate interactions between polymorphonuclear lymphocytes and endothelium, and thus may decrease neutrophil infiltration into tissues.

Calcitonin gene related peptide and N-procalcitonin modulate CD11b upregulation in lipopolysaccharide activated monocytes and neutrophils.

OBJECTIVE: Circulating levels of calcitonin gene related peptide (CGRP) and calcitonin precursors, including procalcitonin (PCT) and its free aminopeptide N-procalcitonin (N-PCT), have been found dramatically increased in septic patients. PCT is known to attenuate the chemotaxis of monocytes in response to chemoattractants. This study examined whether CGRP and N-PCT modulate the LPS-induced expression of CD11b, which is one of the major integrins involved in monocyte and neutrophil chemotaxis during a response to microbial infections. DESIGN AND SETTING: In vitro cell culture study in the immunology laboratory of a university hospital. PARTICIPANTS: Healthy volunteers. MEASUREMENTS AND RESULTS: We assessed the effects of N-PCT and CGRP on CD11b expression on monocytes and neutrophils after LPS (2 ng/ml) or fMLP (10(-8) M) challenges. We used a human whole blood model, and measurements were made by flow cytometry. Both peptides in a dose-dependent manner decreased the LPS- and fMLP-induced rise in CD11b in monocytes and neutrophils. As these peptides are thought to act by raising cAMP, we also mimicked their effects with the use of rolipram and forskolin and found similar results. CONCLUSIONS: These findings are in line with recent studies demonstrating anti-inflammatory properties for this family of peptides. CGRP and calcitonin precursors may function as factors suppressing the propagation of inflammation through the inhibition of several processes involved during a response to a bacterial stimulus.