The predominance of a naive T helper cell subset in the immune response of experimental acute pancreatitis.

INTRODUCTION: In necrotizing acute pancreatitis (NAP), systemic inflammatory response syndrome (SIRS) and the compensatory anti-inflammatory response syndrome (CARS) decide overall outcome and mortality. In patients, low lymphocyte counts were found, but T-helper cells seemed to conversely increase. Our aim was to further categorize T-helper cells within the context of NAP induced SIRS and CARS. METHODS: NAP was induced by injection of sodium-taurocholate into the common bile duct of male BALB/c mice; sham treated animals received saline infusion. The animals were sacrificed at 6, 12, 24 and 48 h later. Lymphocytes from blood, liver and spleen were isolated and examined by flow cytometry. Staining was performed for CD4, CD8, CD19, CD45RB, CD25, CD69, and CD152. CD4+ cells were sorted for their CD45RB expression and sought for gene regulation associated to TH1/TH2 cells by quantitative RT-PCR. RESULTS: In NAP, CD4+ was solely increased in all compartments. CD8+ remained without substantial alterations. CD45RB showed significant expression in RBhigh in T-helper cells, confirmed by the CD45RBhigh/low ratio (Liver, 24 h: NAP 2.2, SHAM 0.6; p < 0.001). CD45RBhigh and -low cells were not associated to patterns of TH1/TH2 expression. In NAP, CCR4 expression was significantly decreased within RBhigh cells (fold change: 0.04, p < 0.05), while TLR6 showed significant overexpression (fold change: 2.36, p < 0.05). CONCLUSION: T-helper cells increase in NAP, leaning towards CD45RBhigh expression. They resemble naive T-cells, in which NAP leads to expression profiles associated with an innate immune response. This suggests new findings in immunological pathomechanisms of NAP.

Inducing a humoral immune response to pancreatic cancer antigen.

BACKGROUND: Patients with pancreatic carcinoma have a grim prognosis. Here, we examine the induction of an in vitro antibody response of human B cells to pancreatic carcinoma antigens. MATERIAL AND METHODS: Cells of five cultured pancreatic ductal adenocarcinoma lines were lysed and their plasma membrane fragments isolated in an aqueous two-phase-system. The plasma membrane fragments were then added to cultures of isolated peripheral blood mononuclear cells from healthy volunteers for 14 days to act as a tumor antigen. Also, we added combinations of IL-2, IL-4, IL-21, anti-CD40 mAb and varying protein concentrations of the plasma membrane fragments to these cultures. We then tested characteristics and binding of resulting IgG and IgM against aforementioned tumor plasma membrane fragments and their respective cells using ELISAs. RESULTS: The combination of IL-2, IL-4 and anti-CD40 mAb elicited IgM production showing significant binding (p<0.05) to plasma membrane fragments. PANC-1 antigen and the combination of IL-4, IL-21 and anti-CD40 mAb was able to produce a significant and specific IgG formation against PANC-1 plasma membrane fragments (p<0.05). Tumor antigen, interleukins and anti-CD40 mAb had a significant impact on the binding capacity of these antibodies (p<0.05). IgG binding pancreatic carcinoma cells was observed when the tumor antigen concentration was increased during stimulation (p<0.05). BxPC3 plasma membrane fragments showed inhibitory effects on IgG binding BxPC3 antigens (p<0.05). CONCLUSIONS: A human anti-tumor antibody formation can be induced in vitro using PANC-1 antigens and B cell stimulating agents. This response has the potential to generate antibodies specific to PANC-1 antigens. PRéCIS: The concept presented is novel and a promising approach to eliciting a specific B cell response to tumor antigen. The method may prove useful in understanding and developing anti-tumor immunity.

Organ-specific monocyte activation in necrotizing pancreatitis in mice.

BACKGROUND: Acute necrotizing pancreatitis (NAP) induces a systemic inflammatory response syndrome. We investigated the underlying changes of monocytes using different activation markers. MATERIALS AND METHODS: A retrograde injection of 2 mL/kg bodyweight of sodium taurocholate into the common bile duct of BALB/c mice induced NAP, whereas sham-operated animals (SOP) were treated with saline. After 6, 12, 24, and 48 h, histologic alterations, pancreatic enzymes, and interleukin 6 in serum, albumin, and myeloperoxidase (MPO) in bronchoalveolar lavage fluid were examined. Isolation of mononuclear cells from the blood, spleen, and liver and the subsequent determination of macrophages (F4/80) and their activation marker CD121b and MHCII (1Ad) were performed by fluorescence-activated cell sorting (FACS analyses). RESULTS: After pancreatitis induction, pancreatic enzymes (amylase: SOP 7008 U/L, NAP 37,044 U/L, P < 0.001) and histologic pancreatic damage (SOP 0.80 ± 1.92, NAP 19.6 ± 0.64, P < 0.001) developed instantly. Pulmonary vascular damage and MPO were detected between 6 and 12 h after onset (6 h albumin SOP 132.0 ± 12.0 µg/mL, NAP 267.2 ± 49.6 µg/mL; P < 0.05; MPO SOP 0.23 ± 0.20 ng/mL, NAP 11.29 ± 3.12 ng/mL, P < 0.01). Blood levels of interleukin 6 increased after 12-24 h (12 h SOP 584 ± 300 pg/mL; NAP 2169 ± 942 pg/mL, P < 0.05), whereas monocytes increased fourfold within 48 h (P < 0.05). Furthermore, pancreatitis increased the percentage of activated monocytes in the blood (6 h and/or 48 h: MHCII (1Ad) 2196%/5.65%; CD121b 51,654%/82,146%). Similar observations were made for monocytes from the liver and spleen. CONCLUSIONS: Although inflammatory mediators increased during 24 h after pancreatitis induction, monocyte activation lasted for at least 48 h. The latter is not limited to blood but also detected in isolated liver and spleen monocytes.

Primary hepatocytes of Tupaia belangeri as a potential model for hepatitis C virus infection.

Hepatitis C virus (HCV) is a major cause of chronic hepatitis worldwide, but the study of HCV infection has been hampered by the lack of an in vitro or in vivo small animal model. The tree shrew Tupaia belangeri is susceptible to infection with a variety of human viruses in vivo, including hepatitis viruses. We show that primary Tupaia hepatocytes can be infected with serum- or plasma-derived HCV from infected humans, as measured by de novo synthesis of HCV RNA, analysis of viral quasispecies evolution, and detection of viral proteins. Production of infectious virus could be demonstrated by passage to naive hepatocytes. To assess whether viral entry in Tupaia hepatocytes was dependent on the recently isolated HCV E2 binding protein CD81, we identified and characterized Tupaia CD81. Sequence analysis of cloned Tupaia cDNA revealed a high degree of homology between Tupaia and human CD81 large extracellular loops (LEL). Cellular binding of E2 and HCV infection could not be inhibited by anti-CD81 antibodies or soluble CD81-LEL, suggesting that viral entry can occur through receptors other than CD81. Thus, primary Tupaia hepatocytes provide a potential model for the study of HCV infection of hepatocytes.

Cytokine expression in colon carcinoma.

BACKGROUND: Cytokines reflect the activity of the immune system. We analyzed the local expression of characteristic cytokines indicating the level of activity of unspecific inflammatory cells, Th1-cells and Th2-cells in colon cancer. MATERIALS AND METHODS: In 25 tumor/ mucosa pairs, IL-1alpha, IL-2, IL-4, IL-5, IL-15, TNF-alpha and IFN-gamma were measured by real-time PCR. RESULTS: There was a significant increase in IL-1alpha, IL-4, IL-5 and TNF-alpha and a significant decrease in IL-2 in tumor tissue compared to normal mucosa. DISCUSSION: The cytokine profile in colon cancer indicates a strong unspecific inflammatory reaction in the tumor tissue represented by high levels of IL-1 and TNF-alpha. The comparatively low level of IL-2 suggests suppression of a specific immunological reaction, namely Th1-cells. It can be hypothesized that this is a result and/or cause of local immune escape mechanisms. Furthermore, there is an activation of TH2 cells in the carcinomas.

Influence of antiseptic agents on interleukin-8 release and transmigration of polymorphonuclear neutrophils in a human in vitro model of peritonitis.

BACKGROUND: The aim of this study was to evaluate the influence of taurolidine (TAU) and polyhexanid (POLY) on basic inflammatory reactions during peritonitis by using an in vitro model of human peritoneum. MATERIALS AND METHODS: Human umbilical vein endothelial cells (HUVEC) and human peritoneal mesothelial cells (HPMC; concentration: 2x10(5)/cm2) were brought on a collagen-coated filter insert with 3-microm pore size (HUVEC on the bottom, HPMC on the top), thus resulting in a two-chamber peritoneal model. After 5 days, confluence of the cells was reached, and HPMC were stimulated with 0.5 mL of TNF-alpha (10 microg/mL) for 4 h. Afterwards, 0.5 mL of TAU (1% and 2%) or 0.5 mL of POLY (0.1% and 0.2%) solution were added to the upper (HPMC) compartment. Polymorphonuclear neutrophils (PMN, 10(6)/mL) were placed in the lower compartment 1 h later. After 2 and 6 h, aliquots were taken from the upper compartment and transmigrated PMN were counted. Interleukin-8 (IL-8) concentrations were measured in both compartments by chemiluminescent enzyme immunometric assay. Expression of the adhesion molecules P-selectin and intercellular adhesion molecule-1 (ICAM-1) was assessed by immunohistochemistry. Controls were either TNF-alpha-stimulated HPMC without any antiseptic agents, or stimulated HPMC where TNF-alpha had been substituted by culture medium. Each experiment was performed in triplicate. RESULTS: Stimulation with TNF-alpha led to a time-dependent increase of IL-8 secretion to the apical compartment resulting in a gradient between both chambers, as well as to a time-dependent increase of PMN transmigration and expression of adhesion molecules. IL-8 gradients and PMN migration were significantly higher as compared to the other groups (p<0.05). After substitution of the stimulus by culture medium, significantly less IL-8 was measured in both compartments. PMN transmigration was almost absent (p<0.05). Addition of POLY and TAU led to comparable low IL-8 gradients with concomitant low PMN transmigration. The initially detected expression of adhesion molecules significantly decreased during the observation time. The IL-8 gradient in all groups correlated significantly with PMN transmigration (r=0.74226; p<0.0001). CONCLUSION: The diminished IL-8 response together with low PMN transmigration rates after addition of TAU and POLY may reflect either antiinflammatory effects or cellular damage.

Severe deficiency of switched memory B cells (CD27(+)IgM(-)IgD(-)) in subgroups of patients with common variable immunodeficiency: a new approach to classify a heterogeneous disease.

Hypogammaglobulinemia is the hallmark of common variable immunodeficiency (CVID) syndrome, a heterogeneous disorder predisposing patients to recurrent bacterial infections. In this study, we investigated the peripheral B-cell compartment of 30 well-characterized CVID patients in comparison to 22 healthy controls. Flow cytometric analysis of peripheral blood lymphocytes revealed a reduction of class-switched CD27(+)IgM(-)IgD(-) memory B cells below 0.4% in 77% of our patients (group I), while this B-cell subpopulation exceeded 0.5% in all healthy donors and in 23% of CVID patients (group II). These results correlate well with the capacity of peripheral blood lymphocytes to produce immunoglobulins in vitro upon stimulation with Staphylococcus aureus Cowan I (SAC) plus interleukin-2 because the production of immunoglobulin G in vitro is entirely dependent on the presence of switched memory B cells. The subdivision of group I into patients with an increased proportion of CD21(-) peripheral B cells (> 20%; group Ia) and patients with normal percentages of CD21(-) B cells (< 20%; group Ib) revealed a significant clustering of patients with splenomegaly and autoimmune cytopenias in group Ia. Based on these observations, we propose a fast and reliable new classification for CVID patients by flow cytometric quantification of class-switched memory and immature B cells in the peripheral blood of patients. Our results point toward defects at various stages of B-cell differentiation in CVID subgroups and support the value of a B-cell-oriented classification principle. A consensus on this new classification system will hopefully provide a tool for rapidly defining homogeneous subgroups of CVID for functional studies and genetic linkage analysis.