M1251

The Effects of Gene Transer of Soluble TGF-I~ Type II Receptor and Soluble VEGF Type I Receptor (Fh-1) in Peritoneal Fibrosis Model of Mice; Balance between Inflammation and Fibrosis Yasuaki Motomura, Hiroshi Kanbayashi, Yikang Deng, Patricia A. Blennerhassett, Peter J. Margetts, Kensuke Egashira, Stephen M. Collins

Vascular endothelial growth factor (VEGF) is upregulated by transforming growth factor-[3 (TGF-~) in several types of cells in vivo and in vitro. While many studies have shown that blockade of TGF-[3 prevented fibrosis, no such studies have examined VEGF. Furthermore undesirable effects of blocking these growth factor signaling at sites of inflammation are still unclear. We investigate the effect of blocking TGF-[3 or VEGF on fibrosis formation using established TGF-13-induced peritoneal fibrosis model. Male C57BL/6 mice were divided into 3 groups, and injected TGF-[3-RII plasmid (50~g DNA) or VEGF-RI (Fit-l) plasmid (501*g DNA) or PBS into anterior tibial muscle with electroporation (6 pulses of 100V for 50ms) under anesthesia (ira). 24hr later, each group was divided into 2 groups and injected 109 PFU adenovirus encoding active TGF-I3 (AdTGF-I322~22~) or PBS intraperitoneally tip). These 6 groups were; (1) AdTGF-~(ip) + TGF-~-RII (ira), (2) AdTGF-I3(ip) + Fit-1 (ira), (3) AdTGF-I3(ip) + PBS (ira), (4) PBS (ip) + TGF-I3-RII (ira), (5) PBS (ip) + Fh-1 (ira), (6) PB5 (ip) + PBS (im), respectively. Mice were eutbanized at day 10, with tissues stained with Masson's trichrome for fibrosis. Tissue hydroxyprofine contents of anterior abdominal wall per unit area were measured. Serum TNF-a, albumin, and serum amyloid protein (SAP), as acute reactant protein, were also measured at various time points. No effect was observed in group 4, 5 and 6. Marked thickening of the peritoneum and increasing hydroxyproline contents were observed in group 3. Both group 1 and 2 showed sagnificant reduction of this collagen deposition. Significant weight loss, hypoahibuminemia, and increasing TNF-a level were observed in group 1 but not in group 2 compared to group 3 at day 7. Moreover, serum SAP level was still significantly higher in group 1 at day 7 compared to both group 2 and 3. These effects of soluble TGF-I3-RII were fatal for animals of this group. These results demonstrate that gene transfer of TGF-I3-RII in fibrous disorder may aggravate inflammation while attenuate fibrosis, and also indicate that TGF-I3 causes fibrosis partly by mediating VEGF in this model and Fh-1 gene transfer may be useful to attenuate fibrosis.

M1252

Cross Talk between Extracellular Signal-Regulated Kinase and p38 Mitogen- Activated Protein Kinase in the Induction of Nod2 Gene in Human Monocytic Cells Hyun-Mee Oh, Eun-Young Choi, Weon-Cheol Han, Suck-Chei Choi, Jay-Min Oh, Chang-Duk Jun, Yong-Ho Nah

BACKGROUND: Nods are members of proteins that have been implicated in the intraceflular recognition of pathogen components. Nodl is broadly expressed in tissues, while the expres- sion of Nod2 seems to be more restricted to monocytes. Nod2 levels are also up-regulated tn myelomonocytic and epithelial cells upon stimulation. In the present study, we have focused the mechanism by which the Nod2 gene is regulated. METHODS: Nod2 and IL-8 mRNA levels were detected by semi-quantitative RT-PCR. Activation of MAP kinase was examined by Western blot analysis. NF-KB activation and NF-KB-dependent transcriptional activity were determined by EMSA and luciferase assay, respectively. RESULTS: Bacterial [ipopolysaccharide (LPS) endotoxin had no significant effect on Nod2 gene expression by itself, whereas phorbol myristate acetate (PMA) alone had modest activity; however, preincubation of cells with PMA followed by endotoxin induced much higher levels of Nod2 mRNA. To define the signaling pathway on PMA and LPS-mediated Nod2 expression, we explored the involvement of mitogen-activated protein kinses (MAPK). A selective MEK1 inhibitor, PD98059, inhibited LPS and PMA-stimulated ERK activation and abolished Nod2 expression, indicating that the ERK cascade mediates the induction of Nod2 by PMA and LPS. In cells treated with an inhibitor of p38 MAP kinase, 5B203580, PMA and LPS-mediated ERK activation became persistent and the induction of Nod2 was significantly augmented. CONCLUSIONS: These results suggest that cross talk in PMA and LPS-mediated ERK activation to induce Nod2 expression is negatively regulated by endogenous p38 MAP kinase activation. These data further suggest that regulation of Nod2 expression by intracellular MAPK may play a crucial role in host innate immune responses evoked by monocytes.

M1253

Differential Cytokine Response of Cells Derived from Different Lymphoid Compartments to Commensal and Pathogenic Bacteria Louise O'Callaghan, Liam O'Mahony, Jane McCarthy, Eamonn Kavanagh, William Kirwan, Paul Redmond, Fergus Shanahan, John K. Collins

Background: The resident host microflora condition and prime the immune system However, systemic and mucosal immune responses to bacteria may be divergent. Thus, in vitro models using ceils derived from the systemic immune system may not accurately reflect the response of mucosal ceils. Aim: To compare, in vitro, cytokine production by mesenteric lymph node cells (MLNCs), mesentenc lymph node derived dendntic cells and peripheral blood mononuclear ceils (PBMCs) to defined microbial stimuli. Methods: Fresh mesemeric lymph nodes were obtained from IBD patients following colon resection (n = 10). Peripheral blood was isolated from a separate group of IBD patients (n = 12) The mononuclear cell populations were isolated using Ficoll-histopaque density cemrifugation MLN derived dendritic ceils were isolated by negative selection t i e T cells, B cells and progenitor cells were removed by antibody labelling and magnetic separation). Isolated cells (purity >95%) were incubated m vitro for 72 hours with the probiotic bactena, Lactobacillus salivarius or B~fidobacterium infantis, or the pathogenic organism Salmonella typhimurium IL-12, TNF-a and IL-10 cytokine levels were quantified by ELISA. Results: PBMCs secreted TNFa in response to the lactobacil- lus, bifidobacteria and salmonella strains, while MLNCs and MLN derived dendritic cells secreted TNFa only in response to salmonella challenge. PBMCs secreted IL-12 following co-incubation with salmonella or lactobacifii, while MLNCs and MLN derived dendritic cells

produced IL-12 only m response to salmonella. PBMCs secreted IL-10 m response to the bifidobacteria cells, but not m response to the lactobacillus or salmonella strain. However, MLNC and dendritic cells secreted IL-10 in response to bifidobacteria and lactobacilli, but not in response to salmonella. Conclusion: Stain-strain divergence in cytokme responses (i.e. commensal versus pathogen) are more marked in cells isolated from the mucosal immune system compared to peripheral blood mononuclear cells. Caution must be exercised when extrapolating biological significance from different in vitro models as cells isolated from different sites will yield variable results.

M1254

CCR6 Deficient Mice with Increased Numbers of a ~ TCR Intestinal lntraepithelial Lymphocytes Exhibit Enhanced Innate Immunity to Infection with the Nematode Heligmosomo/des polygyrns Andreas Luegering, Jan Mead, James T. Hudson III, Torsten Kucharzik, Ifor Williams

Purpose: CCR6 plays a major role in the homeostasis of the intestinal immune system. CCR6 deficient mice have elevated numbers olintraepithelial T lymphocytes (IEL) with predominant expansion of c~ TCR IEL. The IEL in CCR6 deficient mice have an increased proliferative rate and are more likely to have an acnvated phenotype as judged by Thy-1 expression. In vivo models of allergic airway disease have suggested a requirement of CCR6 for efficient induction of IL-5 synthesis and lgE production. This study examined the effect of CCR6 deficiency on the immune response to Hehgmosomoides poIygyrus, a chronic nematode infec- tion of mice associated with a strong Th2-mediated immune response. Methods: Groups of 4 to 6 wild type (WT) and CCR6 knockout mice were orally infected with 100-200 H. polygyrus larvae at 6 to 8 weeks of age. After 14 days, the number of cysts formed in the musculans of the small intestine were counted as an index of the efficiency of with which larvae penetrated the small intestine to reach the muscularis. The shedding of eggs by adult worms was determined by microscopic analysis of fecal material. Total serum IgE was measured by ELISA. Intestinal cytokine production ni uninfected mice was evaluated by ribonuclease protection assay (RPA). Results: Oral infection of CCR6 deficient mice with H. polygyrus larvae resulted in a significant reduction in the number of cysts at 14 days compared to WT controls (60% and 52% of WT level in two experiments; p = 0.032 and p = 0.006). Correspondingly, the CCR6 deficient mice also showed a reduced worm fecundity as mea- sured by the total number of eggs recovered from the intestine (54% and 52% of WT level). H. poly,~rus infection of CCR6 deficient mice resulted in strong induction of serum lgE levels to a level just below that of WT mice (77% of WT level). RPA analysis of intestinal cytokine production did not reveal any effect of CCR6 deficiency on the basal level of mRNA for IL-4, -5, and -13. Conclusions: The reduced numbers of cysts and eggs in H. polygyrus- infected CCR6 deficient mice indicate that CCR6 deficient mice have increased innate immune effector activity against the infective larvae. We proposa that the increased innate resistance of CCR6 deficient mice to nematode infection is mediated by the expanded population of activated al3 TCR [EL. We also conclude that efficient induction of an IgE response in response to an intestinal infection with a parasite can occur in the absence of CCR6.

M1255

Effect of High-Fat Enteral Nutrition on Inflammation and Gut Barrier Function in Rats after Hemorrhagic Shock Misha D. Luyer, Jan A. Jacobs, M'Hamed Hadfoune, Anita C. Vreugdenhil, Cornelis H. Dejong, Wire A. Buurman, Jan Willem M. Greve

Purpose: Microbial toxins, hke endotoxin play a central role in the pathogenesis of sepsis after severe hemorrhage. Translocation of endotoxin in the gut has been hypothesized to trigger production of inflammatory cytokines and cause gut barrier failure. Triacylg[ycerd- rich fipoproteins are potent scavengers of endotoxin and are physiologically upregulated by oral fat intake. We investigated the effect of high-fat enteral nutrition on plasma endotoxin, TNF-c~ and gut barrier function in rats after hemorrhagic shock. Methods: Anaesthetized Sprague-Dawley rats were subjected to a non-lethal hemorrhagic shock without resuscitation by withdrawing 2.1 ml blood/100 gram body weight. Hemorrhagic shock rats were divided into a group that was starved overnight (HS-S); a group receiving low-fat enteral nutrition (HS-LF) and a group receiving high-fat enteral nutrition (HS-HF). Ninety minutes after shock arterial blood was withdrawn, gut barrier function was assessed ex vivo by measuring horseradish peroxidase (HRP) leakage in a segment of ileum and by determining bacterial translocation to mesenteric lymph nodes (kILN) by culture. Results: Plasma endotoxin in HS-HF rats (3.9 -+ 0.6 pg/ml) was significantly lower in contrast to HS-S rats (15.2 ___ 2.2 pg/ml, p=0.001) and HS-LF rats (10.7 + 0.9 pg/ml, p=0.002). TNF-a levels were dramatically decreased in HS-HF rats (17.9 - 10.4 pg/m[) compared with HS-S rats (180.9 _+ 67.9 pg/ml, p<0.02) and HS-LF rats (83.5 _+ 16.7 pg/ml, p<0.01). Also HRP leakage in HS-HF rats (1.1 + 0.4 ~g/ml) was strongly reduced compared with HS-S rats (4.2 • 1.1 ixg/ml, p < 0.05). Moreover, bacterial translocation to MLN was lower in HS-HF rats (median 5 cfu/gram tissue, (range 0-26)) compared with HS-S rats (80 cfu/gram, (39-135), p<0.01) and HS-LF rats (41 cfu/gram, (5-103), p<0.01). Conclusions: This study is the first to show that high-fat enteral nutrition specifically decreases endotoxin and TNF-ct in plasma and at the same time preserves gut barrier function and reduces bacterial translocation after hemorrhagic shock. Preoperative high-fat enteral nutrition may provide a new therapy in preventing the systemic inflammatory response preceeding sepsis.

M1256

PPAR'y activation inhibits interferon-~/stimulated STAT1 and JNK phosphorylation in epithelial cells Chen Ma, Katherine Schaefer, Shuping Zhao, Lawrence Saubermann

Background: The nuclear transcription factor, peroxisome prolfferator-activated receptor- gamma (PPAR"/) is highly expressed in intestinal epithelial cells. After activation, PPARy has been demonstrated to reduce innate anti-inflammatory responses, such as chemokine

A-339 AGA Abstracts

release. This inhibitory response has been confirmed in murine colitis models and PPAR~/ heterozygotic animals. The cellular mechanisms of PPAR'fs inhibitory effects have not been clearly identified. Our investigations into IFN~/activated epithelial cells indicate that PPAR~ may reduce kinase activity involved in transcriptional regulation of these innate inflammatory processes. Methods: HT-29 human epithelial cells (0.1 million cells/well) were seeded and grown to 70-80% confluence. Cells were incubated with the PPAR~ agonist, rosiglitazone[lO0 p.M], in 0.1% DMSO, or 0.1% DMSO alone, respectively, 24 hrs before adding IFN-~ (1000 U/ml). Cell extracts were obtained at O, 15, 30, 60, and 180 minute time points. Western blots were performed using rabbit polyclonal IgG antibodies for Signal transducer and activator of transcription 1 (STAT1), Phospho-STAT1 Tyr701, and c-Jun N-terminal Kinase 0NK), and appropriate detection antibodies as per manufacturer's suggestions. Results: After IFN-'y stimulation, PPAR~ pre-activation reduced levels of phosphorylated STAT1 in comparison to non-PPAR~/treated HT29 epithelial cells. There was no reduction in total STAT1 levels between samples. In addition, there was also a reduction in the levels of phosphorylated JNK in the PPAR'/treated epithelial cells following activation of IFN~/. This reduction was observed to be greatest at the 60 and 180 minute time points. Conclusions: PPAR',/activation reduces kinase activity and the phosphoryfation of important pro-inflamma- tory transcriptional regulatory factors by intestinal epithelial cells. There is inhibition of the IFN~/-associated STAT1 phosphorylation, which implies PPAR~/inhibition of Janus family protein tyrosine kinase OAK) activity. In addition, there is a reduction in the inflammatory mitogen-activated protein kinase (MAPK) associated JNK phosphorylation by PPAR"/activa- tion. These results indicate an important regulatory role of PPAR"/agonists in reducing pro- inflammatory innate immune responses by epithelial cells.

M1257

Increase in the Number of Dendritic Cells Expressing High Levels of CD80 Within the Intestinal Lamina Propria of Mice with Colitis Ulrike G. Strauch, Nicole Grunwald, Florian Obermeier, Michael Schnltz, Sonja Guerster, Juergen Schoelmerich, Heiko C Rath

Introductinn: Inflammatory bowel disease is a chronic inflammatory condition of the intestine with still unknown etiology. Recent data suggest that gut inflammation may result from a dysregulated immune response toward bacterial antigens induced by antigen presenting ceils e.g. dendritic cells (DC) within the intestinal mucosa, leading to sustained overproduction of proinflammatory cytokines and mediators. Aim of the present study was to investigate possible differences in distribution and activation status of DC within the intestinal lamina propria and mucosa associated lymphoid tissues of mice before and after induction of colitis. Methods: Colitis was induced by transfer of CD4+CD62L+ splenic T lymphocytes into immunodeficient syngenic recipients and acute colitis in normal mice by application of 5% DSS in drinking water over a time period of 7 days. After onset of intestinalinflammation tissue was harvested and immunohistochemistry was performed using an anti-CD 1 lc antibodies as marker for DC and antibodies against the costimulatory molecules CD40, CD80 and CD86 as activation markers. Results: A marked increase of infiltrating CD1 lc + dendritic cells was found within the inflamed lamina propria compared to healthy animals as detected by immunohist ocbemistry. Mesenterial lymph nodes of mice with colitis showed a slight increase in the number of dendritic cells whereas no changes regarding DC numbers were seen in Peyers patches and the spleen. In addition dendritic cells within the inflamed mucosa expressed high levels of CD80, a costimulatory molecule that is thought to be required for Thl responses. In contrast no upregufation of CD40 or CD86 was detected. Conclusion: Exploring two different models of colitis, gut inflammation is accompanied not only by increased numbers of T cells within the intestinal lamina propria but also by a marked infiltration of CD1 lc + dendritic cells within the lamina propria. These cells express high levels of CD80 resembling a phenotype of mature DC, whereas no upregulation of other costimulatory molecules could be detected. Therefore it can be hypothesized that antigen presentation via actwated dendritic cells within the intestinal mucosa plays a role in the onset or/and perpetuation of the disease

M1258

Interferon-gamma modulates LPS-responsiveness in Human Intestinal Epithelial Cells through Coordinated Up-regulation of LPS-uptake, and Expression of Intracenular TLR4/MD-2 Complex Manabu Suzuki, Tadakazu Hisamatsu, Tomohiro Terada, Daniel K. Podolsky

Background &/Sam: Intestinal epithelial cells (IECs) provide a structural and functional barrier against to luminal bacteria and their pathogenic components. Although some IEC lines are known to respond to LPS, understanding about the relationship between LPS responsiveness and the expression of LPS receptors or factors regulating LPS responsiveness is incomplete. Accordingly, we examined LPS responsiveness and expression of TLR4 and MD2 in commonly studied human IECs. Materials & Methods:l)LPS responsiveness was examined using IL-8 ELISA in SW480, HT29, Colo205, HCT116, and Caco2 with/without IFNg stimulation. 2)Effect of IFNg on TLR4 and MD2 mRNA expression in IEC lines was examined by Northern blot and RT-PCR. 3)TLR4 and MD2 mRNA expression was assessed in primary IECs by single cell isolation RT-PCR. 4)TLR4 protein expression in IEC lines was examined by immunoprecipitation and immunoblotting 5)Surface expression of TLR4 and CD 14 in IEC lines was analyzed by FACScan. 6)internalization of Alexa-488-conjugated LPS by HT29 and Colo205 was analyzed by FACSan and fluorescent microscope. Results: 1) IEC lines could be separated into three different functional classes on the basis of LPS responsiveness. The first is relative hypo-responsive to LPS (HCT116 and Caco2). The second exhibits a highly LPS-responsive phenotype (SW480). The third exhibits that LPS- responsiveness was inducible by IFNg (HT29, Colo205). 2)IFNg up-regulated TLR4 and MD2 mRNA expression in HT29 and Colo205.3)Both TLR4 and MD2 mRNA were expressed in isolated primary IECs. 4)TLR4 protein was expressed in SW480, HT29, and Colo205. 1FNg up-regulated TLR4 protein expression in both HT29 and Colo205.5)Surface CD14 expression was not detected in either SW480 or HT29 with or without IFNg pre-treatment. Significant CD14 expression was observed in Colo205. Surface expression of TLR4 was observed in SW480. Although TLR4 protein was expressed in HT29 or Colo205, surface expression of TLR4 was not detected. 6)LPS incorporation vaned among the cell lines. IFNg

up-regulated LPS-uptake in Colo205. Conclusion: LPS responsiveness is variable in 1ECs. Pro-inflammatory cytokines, IFNg can modulate LPS responsiveness through several mecha- nisms ni IECs. These results provide insights into the mechanisms of LPS recognition in IECs and into the processes through which pro-niflammatory cytokine affect LPS responsiveness in mucosal inflammation.

M1259

Susceptibility of Three Strains of Rag2-Deficient Mice to Helicobacter hepaticas - Induced Colitis and Colorectal Cancer Susan E. Erdman, Theophflos Poutnhidis, Arfin B. Rogers, Michael Tomszaki, Bruce Horwitz, James G. Fox

Background. Inflammatory bowel disease (IBD) and colorectal cancer are debilitating human diseases. The role of genetic and environmental factors that contribute to pathogenesis in the bowel have been the focus of much investigation. We recently developed a mouse model to study innate immune driven colitis and colon cancer with elevations in Type 1 cytokines by infecting 129/SvEvRag2-deficient mice with Helicobacter hepaticus. The rapid progression of disease supported an earlier report by Berg et al, 1996 that mice on the 129/SvE background were highly susceptible to IBD. Methods. To further examine the influence of strain genetic background on microbtafly-indueed diseas~progression, three different Rag2-deficient mouse strains: C57BL/6Rag2, BALB/cRag2 and 129SvEvRag2 mice were orally nifected with H. hepaticus at 6-8 weeks of age. Control groups for all mouse strains were sham-dosed at the same age. Results. While 129/SvEvRag2 mice developed severe colitis and lower bowel cancer within 3 months post infection, BALB/cRag2 and C57BL/6Rag2 mice developed moderate or minimal colitis and neither strain developed colon cancer. No lesions were found in any of the control groups. Conclusions. These results indicate that innate immune factors contribute to the differences in susceptibility to cohos and cancer between these mouse strains. Interestingly, the results fit the strain differences reported by Berg et al in [LIO j mice with IBD. Characterization of H. hepaticus colonization and host cytokine expres- s/on between strains will help elucidate the specific immune factors that contribute to the differences between these strains. The Rag2-deficient model should provide important insights into understanding the role of innate immunity in the pathogenesis of 1BD-associated lower bowel cancer in humans.

M1260

Dual Role of Toll-Like Receptor (TLR)4 in Septic Peritonitis in Mice: Protection by TLR4 During Initial Infection Is Lost when Peritonitis Complicates Acute Pancreatitis David Van Westerloo, Sebastiaan Weijer, Marco Bruno, Alex De Vos, Tom Van der Poll

Background: Pancreatitis is frequently complicated by Gram-negative infections. TLR4 plays a major role in the antibacterial host defense against Gram-negative infection; however, little is known about the role of TLR4 during infections complicating critical illness such as pancreatitis. Aim: To determine the influence of pancreatitis on the host response to abdomi- nal sepsis caused by Eschenchia cull in TLR4 competent and deficient mice. Methods: Wild type (Wt, C3H/HeN) and TLR4 mutant (C3H/HeJ) mice received an intraperitoneal injection with 5"104 CFU E.coli, preceded by 12 hourly injections of either cerulein (50ug/kg/hour) to induce pancreatitis or saline (sham). Results: TLR4 deficient mice subjected to peritonitis displayed a reduced ability to clear E.coli, as reflected by more CFU in peritoneal lavage fluid, liver and blood (all P<0.05 vs Wt). In separate experiments, pancreatitis developed comparably in Wt and TLR4 mutant mice. If peritonitis was preceded by acute pancreatitis, there was a marked decrease in host defense in Wt mice (CFU in PLF, blood and liver all higher in pancreatitis/peritonitis mice, P<O.05 vs sham/peritonitis); however, this decreased host defense was absent in TLR4 mutant mice with pancreatitis/peritonitis. Conclusions: 1. TLR4 is important for host defense against E.coli induced septic peritonitis. 2. Pancreatitis reduces host defense to abdominal sepsis caused by E.coli in Wt mice. 3. The role of TLR4 in host defense against E.coli peritonitis is lost if this infection complicates pancreatitis.

M1261

Lactobacillas reuteri Decreases TNF-ct Production in Lipopolysaccharide- Activated Murine Macrophages by a Contact-lndependent Mechanism Jeremy A. Pena, James Versalovic

Animal studies and human clinical trials have shown that Lactohacfllus can prevent or ameliorate inflammation in chronic colitis. However, molecular mechanisms for this effect have not been clearly elucidated. We hypothesize that lactobacifli are capable of down- regulating pro-inflammatory cytokine responses induced by the enteric microbiota. We investigated whether murine and human-derived factobacilli diminish production of tumor necrosis factor alpha (TNF-a) by primary peritoneal (from 129Sv strain) and RAW 264.7 gamma (NO-) macrophages, and alter the TNF-a/interleukin-10 (IL-IO) balance, m vitro. When media conditioned by some isolates of L. reuteri, and a related species isolated from a human individual, Lactobacillus coryneformis, are co-incubated with endotoxin/ lipopolysaccharide (LPS), TNF-a production is significantly inhibited compared to controls. Both mouse and human L. reuteri strains decrease TNF-c~ production by up to 50%. Similarly, L. coryneformis reduced TNF-a levels in conditioned media-treated macrophages, while IL- l0 synthesis is unaffected, resulting in a net immunoregulatory effect. To determine whether the L. reuteri strains used were clonal, genomic fingerprint analysis was performed by repetitive element PCR (rep-PCR). We find that L. reuteri strains exhibiting TNF-a inhibitory properties are polyclonal. Additionally, mucin binding assays indicate no correlation between mucni binding and TNF-a inhibitory properties. When comparing human isolates, L. cory- neformis significantly binds mucin while L reuteri does not. Lactobacillus species may be capable of producing soluble molecules that inhibit TNF-a production in activated macrophages. Since overproduction of pro-inflammatory cytokines, especially TNF-a, is implicated in pathogenesis of chronic intestinal inflammation, enteric Lactobacilhis-mediated inhibition of pro-inflammatory cytokine production and alteration of cytokine profiles may

AGA Abstracts A-340