ovalbumin and Escherichia-coli-Infections

Allergic asthma, characterized by chronic airway Th2-dominated inflammation, is associated with an increased risk of infection; however, the underlying mechanisms are unclear. Forkhead box protein A2 (Foxa2) plays a critical role in Th2 inflammation and is associated with pulmonary defenses. To determining the role of Foxa2 in Th2-dominated lung inflammation against the invading bacteria, we established a mouse OVA-sensitized model, an Escherichia coli lung invasion model, and mice with conditional deletion of Foxa2 in respiratory epithelial cells. The number of bacteria in the lung tissue was counted to assess clearance ability of lung. Lung inflammation and histopathology was evaluated using HE and PAS staining. It was found that OVA-sensitized mice had decreased E. coli clearance, reduced Foxa2 expression, and decreased DEFB1 secretion. Conditional deletion of Foxa2 in respiratory epithelial cells led to decreased clearance of E. coli and impaired secretion of DEFB1, similar to the OVA-induced allergic condition. The impaired secretion of DEFB1 may be responsible for the increased risk of infection in the Th2-dominated airway inflammation. Dual luciferase assay demonstrated that Foxa2 regulates DEFB1 expression by affecting its promoter activity in HBE cells. Our study indicated that Foxa2 plays an important role in Th2-dominated airway inflammation against invading bacteria. Conditional deletion of Foxa2 in respiratory epithelial cells can reduce pulmonary's defense against bacterial invasion by inhibiting DEFB1expression.

Topics: Animals; Asthma; beta-Defensins; Cell Line; Disease Models, Animal; Escherichia coli Infections; Female; Gene Deletion; Gene Expression Regulation; Hepatocyte Nuclear Factor 3-beta; Humans; Mice; Ovalbumin; Th2 Cells

Hapten-carrier conjugate immunization is an important tool in the generation of hapten-specific antibodies for analytical purposes and in the uncovering of basic vaccine-immunological mechanisms. The affinity of antibodies is known to play an important role for the resulting sensitivity of antibody-based assay systems and in deciding whether a vaccine-induced antibody response will be protective. With ovalbumin as a carrier protein and a peptide (7.2 NY) representing a 19 amino acid sequence from the E. coli-derived Verotoxin 2e as a model hapten we investigated whether it was possible to influence the affinity and titre of antibodies raised against the hapten using different conjugation ratios and orientations. The peptide was coupled to ovalbumin in four conjugation ratios and two molecular orientations - terminal and central - and the conjugates were verified by mass spectrometry. Mice were immunised ten times at two-weeks intervals with low doses of the eight conjugates. Blood samples collected between each immunisation were analysed by ELISA for specific antibody titres and relative affinities. With both types of conjugations, the anti-peptide antibody titres increased in response to increasing conjugation ratios, but central conjugation resulted in markedly higher titres than terminal conjugation. The overall anti-peptide antibody affinities reached approximately similar levels with both orientations, whereas a reversed proportionality was observed between conjugation ratio and antibody affinity for terminal conjugation. Thus, it appears that the molar ratio of a peptide and its carrier may affect the resulting antibody affinities, and that a conjugation ratio between a terminally conjugated peptide and its carrier approaching one will result in relatively high antibody affinities. Furthermore, the molecular orientation of the coupled peptide has a major effect on the anti-peptide antibody titres induced.

Topics: Amino Acid Sequence; Animals; Antibodies; Antibody Affinity; Cross-Linking Reagents; Enzyme-Linked Immunosorbent Assay; Escherichia coli; Escherichia coli Infections; Female; Haptens; Immunization; Immunoconjugates; Mice; Molecular Sequence Data; Ovalbumin; Peptide Fragments; Shiga Toxin 2; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

Secreted IgA plays a pivotal role in the mucosal immunity to maintain the front line of body defense. We found that the level of fecal IgA was dramatically decreased in aged (NZB x NZW)F(1) (BWF(1)) mice developing lupus nephritis, whereas levels in similarly aged New Zealand Black (NZB) and New Zealand White (NZW) mice remained unchanged compared with young mice. The number of cells obtained from Peyer's patches was markedly decreased in aged BWF(1) mice. Aged BWF(1) mice showed increased susceptibility to pathogenic bacterial infection. Furthermore, oral administration of OVA failed to inhibit secondary IgG response induced by systemic immunization, suggesting defective oral tolerance in aged BWF(1) mice. A significant amount of orally administered OVA was incorporated directly into the intestinal lamina propria in aged BWF(1) mice whereas it was mainly localized in subepithelial domes and interfollicular region in Peyer's patches in young mice. T cells obtained from renal and pulmonary lymph nodes of aged BWF(1) mice that had been orally administered with OVA showed an Ag-specific T cell proliferation, whereas those from young BWF(1), aged NZB, and aged NZW mice did not. Interestingly, aerosol exposure to OVA of aged BWF(1) mice, which had been orally administered with the same Ag, provoked an eosinophil infiltration in the lung. These results demonstrate that mucosal immunity in the gut is impaired and oral Ags induce systemic sensitization instead of oral tolerance in the development of murine lupus.

Topics: Administration, Inhalation; Administration, Oral; Aging; Animals; Antigens; Cell Movement; Crosses, Genetic; Eosinophilia; Escherichia coli Infections; Female; Genetic Predisposition to Disease; Hydrazines; Immune Tolerance; Immunity, Mucosal; Immunoglobulin A; Intestinal Mucosa; Lupus Erythematosus, Systemic; Lupus Nephritis; Lymphocyte Activation; Mice; Mice, Inbred NZB; Ovalbumin

Both B subunit of Shiga toxin 1 (Stx1-B), which mediates the binding of toxin to the membrane, and mutant Stx1 (mStx1), which is a non-toxic double-mutated Stx1 harboring double amino acid substitutions in the A subunit, possess potent mucosal adjuvant activity. Nasal immunization of mice with ovalbumin (OVA) plus the Stx1-B or mStx1 induced OVA-specific serum IgG and mucosal IgA responses. IgG subclass analysis revealed that mStx1 and Stx1-B as mucosal adjuvants supported Ag-specific IgG1 followed by IgG2b Abs. The co-administration of either mStx1 or Stx1-B with OVA enhanced the production of IL-4, IL-5, IL-6 and IL-10 with low IFN-gamma, by OVA-specific CD4+ T cells. To better elucidate the mechanisms underlying mStx1's and Stx1-B's adjuvant activity, we next sought to examine whether or not dendritic cells (DC) residing in the nasopharyngeal-associated lymphoreticular tissue (NALT) were activated by nasal administration of Stx1-B or mStx1. We found that mice nasally administered with Stx1-B or mStx1 showed an up-regulation in the expression of CD80, CD86 and especially CD40 on NALT DCs. Taken together, these results suggest that non-toxic Stx derivatives could be effective mucosal adjuvants for the induction of Th2-type, CD4+ T cell mediated, antigen-specific mucosal IgA and systemic IgG Ab responses, and that they likely owe their adjuvant activity to the up-regulation of co-stimulatory molecules including CD80, CD86 and CD40 on NALT DCs.

Topics: Adjuvants, Immunologic; Administration, Intranasal; Animals; Antigens, CD; B7-1 Antigen; B7-2 Antigen; CD4-Positive T-Lymphocytes; CD40 Antigens; Dendritic Cells; Enzyme-Linked Immunosorbent Assay; Escherichia coli; Escherichia coli Infections; Flow Cytometry; Immunity, Cellular; Immunity, Mucosal; Immunization Schedule; Lymphocytes; Membrane Glycoproteins; Mice; Mice, Inbred C57BL; Mutagenesis, Site-Directed; Nasopharynx; Ovalbumin; Shiga Toxin 1; Up-Regulation

An enterohemorrhagic Escherichia coli (EHEC) O157 oral infection murine model was established to examine the potentiating activity of drugs on mucosal immune responses. Groups of ICR mice inoculated intragastrically with 10(11) CFU/kg EHEC O157 showed chronic intestinal infection with the pathogen that persisted over 3 weeks and resulted in the synthesis of relatively high levels of antigen specific fecal IgA antibody. Intraperitoneal administration of 80 NU/kg Neurotropin, an immunopotentiator, augmented the antigen specific mucosal immune responses to EHEC O157. On the other hand, FK506 clearly suppressed the response. To further document the augmenting effect of Neurotropin on mucosal immune responses, mice were immunized intranasally with a mixture of ovalbumin and cholera toxin. Co-administration of 80 NU/kg Neurotropin significantly potentiated the synthesis of fecal IgA and serum IgG antibodies. These results suggest that Neurotropin has potential as a mucosal adjuvant to promote secretory IgA antibody production and that the mice model of oral infection with EHEC O157 is useful for immunopharmacological studies of bacterial infection-defensive mucosal immune responses.

Topics: Adjuvants, Immunologic; Administration, Intranasal; Animals; Antibodies, Bacterial; Antibody Formation; Disease Models, Animal; Enterotoxins; Escherichia coli Infections; Escherichia coli O157; Feces; Female; Gastric Mucosa; Immunity, Mucosal; Immunoglobulin A; Immunoglobulin G; Injections, Intraperitoneal; Mice; Mice, Inbred ICR; Ovalbumin; Polysaccharides; Tacrolimus

The study examined the effects of stressors on the responses of 3 and a half-week old piglets that had been given an oral dose of enterotoxigenic Escherichia coli (ETEC) and a novel harmless antigen (ovalbumin). Removal from the sow (WEAN), a short-term cold stressor (12;C for 48 hours) (TEMP) and mixing with non-littermates (MIX) were assessed in terms of the effects on faecal shedding of ETEC, immune responses, weight gain and an ACTH stimulation test. WEAN and TEMP reduced weight gain and all stressors increased faecal shedding of ETEC. All stressors increased the IgG responses to F4(K88)ac antigens and WEAN and TEMP increased the IgA responses to the same antigens, probably as a result of increased intestinal proliferation of ETEC. None of the stressors, however, had significant effects on antibody responses to ovalbumin or on lymphocyte proliferation assays. The results indicate that stressors influence the faecal shedding of ETEC in young piglets by a mechanism that may not involve modulation of immune responses.

Topics: Adrenocorticotropic Hormone; Animals; Antigens, Bacterial; Antigens, Surface; Cold Temperature; Escherichia coli; Escherichia coli Infections; Escherichia coli Proteins; Feces; Female; Fimbriae Proteins; Housing, Animal; Hydrocortisone; Immunity, Cellular; Immunoglobulin A; Immunoglobulin G; Lymphocyte Activation; Male; Ovalbumin; Stress, Physiological; Swine; Swine Diseases; Time Factors; Weaning; Weight Gain

The clonal expansion and anatomic location of microbe-specific CD4+ Th cells was studied by tracking the fate of adoptively transferred DO11.10 TCR transgenic T cells specific for OVA peptide 323-339/I-Ad in BALB/c mice infected s.c. with Escherichia coli expressing a MalE-OVA fusion protein. After infection, the DO11.10 T cells accumulated in the T cell-rich paracortical regions of the draining lymph nodes, proliferated there for several days, and then moved into the B cell-rich follicles before they slowly disappeared from the lymph nodes. These changes occurred despite the fact that viable organisms were never found in the lymph nodes. The DO11.10 T cells also accumulated in the s.c. infection site, but about 1 day later than in the draining lymph nodes. Injection of purified MalE-OVA fusion protein alone induced a transient accumulation of DO11.10 T cells in the paracortical regions, but these T cells never entered follicles and the mice did not produce anti-OVA antibodies. The DO11.10 T cells that survived in animals injected with MalE-OVA alone were hyporesponsive to in vitro Ag restimulation and did not produce IL-2 and IFN-gamma, whereas DO11.10 T cells from mice infected with MalE-OVA-expressing bacteria produced both lymphokines. These results suggest that Ag-specific T cells are first activated in secondary lymphoid organs following primary bacterial infection and then migrate to the infection site. Furthermore, productive activation of the T cells during the primary response is dependent on bacterial components other than the Ag itself.

Topics: Adoptive Transfer; Animals; ATP-Binding Cassette Transporters; Carrier Proteins; CD4-Positive T-Lymphocytes; Cell Movement; Cells, Cultured; Epitopes; Escherichia coli; Escherichia coli Infections; Escherichia coli Proteins; Immune Tolerance; Injections, Subcutaneous; Lymph Nodes; Lymphocyte Activation; Maltose-Binding Proteins; Mice; Mice, Inbred BALB C; Mice, Transgenic; Monosaccharide Transport Proteins; Ovalbumin; Peptide Fragments; Periplasmic Binding Proteins; Recombinant Fusion Proteins; Skin Window Technique

The aim of this study was to compare the local gut immune response in sensitized and orally tolerized experimental animals. The development of IgE/IgG antibodies and the DTH to OA was studied in rats made orally tolerant to OA and compared with sensitized control rats after colonization with an Escherichia coli genetically engineered to produce OA. At 3 weeks of age, pups were weaned onto a standard diet without OA or an OA-containing diet for 4 weeks and then switched to a standard diet without OA. Both groups of rats were parenterally immunized with a mixture of OA and human serum albumin (HSA) in Freund's complete adjuvant when they were 8 weeks old. After DTH measurement 2 weeks later, all rats were colonized with an E. coli producing OA for 5 days. The local immune response in the small intestine was assessed, using immunohistochemistry, as the expression of MHC class II molecules and IL-2 receptor (IL-2R) alpha-chain. The OA-tolerant rats showed the classical signs of oral tolerance, with a reduced IgE and IgG antibody and DTH response to OA before colonization. The difference between the two groups in the anti-OA antibody response became even more pronounced after colonization with the E. coli that produce OA. Rats orally tolerant to OA maintained a normal villus architecture after colonization, with a normal expression of MHC class II molecules similar to non-treated adult rats, but with a significantly higher (P = 0.004) expression of IL-2R alpha-chain on T cells in the lamina propria of the villus core compared with sensitized control rats. The tolerant rats showed a very weak staining with the anti-IL-2R alpha-chain-specific antibody on a few goblet cells in only one out of seven rats. In the sensitized control rats, a marked local immune response was seen with an intense staining with a monoclonal anti-IL-2R alpha-chain-specific antibody on goblet cells in five out of seven rats (P = 0.019) and also an increased expression of MHC class II molecules in the epithelial cells and cells in the lamina propria of all rats. Rats orally tolerant to OA maintained a normal villus architecture after colonization, but with a significantly higher (P = 0.004) expression of IL-2R alpha-chain on T cells in the lamina propria of the villus core compared with sensitized control rats. The novel finding that goblet cells express IL-2R alpha-chain and the striking difference in expression of the receptor and the numbers of goblet cells between tolerant and sensitiz

Topics: Administration, Oral; Animals; Bacteriological Techniques; Basement Membrane; Escherichia coli; Escherichia coli Infections; Female; Genetic Vectors; Immune Tolerance; Immunization; Intestinal Mucosa; Ovalbumin; Rats; Rats, Sprague-Dawley; Receptors, Interleukin-2; T-Lymphocytes

The intestinal barrier properties are impaired during inflammation and sepsis, but the mechanisms behind this are unknown and were therefore investigated during experimental sepsis in rats.. The different-sized intestinal absorption markers 51Cr-labeled ethylenediaminetetraacetic acid (EDTA) and ovalbumin were gavaged to rats made septic by intra-abdominal bacterial implantation and to sham-operated rats. Regional tissue permeability was measured in diffusion chambers, and intestinal transit was evaluated by intestinal accumulation of gavaged 51Cr-EDTA.. In comparison with the sham-operated rats, septic rats had higher 51Cr-EDTA levels in blood and urine and showed a prolonged intestinal transit. Septic rats also had a lower tissue permeability to both markers in the small intestines but higher permeability to ovalbumin in the colon. Rats receiving morphine to decrease intestinal motility showed similar changes, with a decreased intestinal transit and increased marker absorption.. The results suggest that the increased intestinal absorption during sepsis was due to regional permeability changes and prolonged intestinal transit.

Topics: Animals; Bacteroides fragilis; Bacteroides Infections; Chromium Radioisotopes; Edetic Acid; Escherichia coli Infections; Gastrointestinal Transit; Intestinal Absorption; Male; Ovalbumin; Rats; Rats, Sprague-Dawley; Sepsis; Time Factors

The immune response to ovalbumin (OA) and the bacterial antigens, lipopolysaccharide (LPS) and fimbriae were studied in conventional rats colonized from birth with an Escherichia coli strain producing OA. The colonized rats had developed IgE antibodies against OA, but not against the fimbrial or the LPS antigens from the E. coli at 2 months of age. At this time all rats were primed with OA given intracutaneously in Freund's complete adjuvant. Two weeks later the colonized rats showed a 35% greater delayed-type hypersensitivity (DTH) reaction to OA, measured as ear swelling, than the controls. Thus bacteria carrying antigens resembling potential allergens might aggravate, or participate in the induction of allergic symptoms. In addition such bacteria could be efficient vaccine vectors in protection against parasites. The study illustrates the importance of the mode of antigen presentation for the subsequent immune response.

Topics: Animals; Antigens, Bacterial; Escherichia coli; Escherichia coli Infections; Female; Hypersensitivity, Delayed; Immunoglobulin E; Immunoglobulin G; Ovalbumin; Rats; Rats, Inbred Strains

The induction of avidin in chick tissues was found in septic Escherichia coli infection. Avidin concentrations in the plasma roughly corresponded to those in the other tissues studied which suggests that avidin in chicks is a secretory protein.

Topics: Animals; Avidin; Chickens; Escherichia coli Infections; Ovalbumin; Poultry Diseases

Topics: Anaphylaxis; Animals; Antibodies; Antigens; Colostrum; Digestive System; Escherichia coli Infections; Female; Hypersensitivity, Immediate; Immunization, Passive; Liver; Lung; Maternal-Fetal Exchange; Myocardium; Ovalbumin; Pregnancy; Skin Tests; Swine; Swine Diseases