ovalbumin and Enterocolitis

Developing countries have a low incidence of inflammatory bowel disease (IBD), perhaps prevented by the high prevalence of helminth infections and other alterations in intestinal flora and fauna. Helminth infections prevent colitis in various murine models of IBD. IBD may be driven by an aberrant immune response to luminal antigen(s).. We developed a murine model of IBD in which gut injury was induced by a specific antigen to better simulate the IBD disease process and to determine if helminth infections could abolish gut injury induced by an orally administered antigen. The model features pan-enterocolitis triggered by feeding ovalbumin (OVA).. The intestinal inflammation is antigen-specific and generates interleukin (IL)-17 and interferon-gamma (IFN-γ), but not IL-4. Full expression of the disease required T cells with defective capacity to make IL-10 and treatment with a noninjurious, low dose of a nonsteroidal antiinflammatory drug. Exposure to Heligmosomoides polygyrus abrogated this antigen-induced gut injury. H. polygyrus colonization induced Foxp3(+) T regulatory cells (Tregs) and mucosal production of IL-10 from non-T cells. Lamina propria mononuclear cells from H. polygyrus-infected mice released less IL-17 and IFN-γ constitutively and when stimulated with OVA or anti-CD3/CD28 monoclonal antibodies.. We developed a murine IBD model featuring antigen-specific enterocolitis and demonstrate for the first time that gut inflammation induced by an antigen could be abrogated by H. polygyrus infection. Protection was associated with suppressed IL-17 and IFN-γ production, induction of Foxp3(+) Tregs, and elevated secretion of non-T-cell-derived IL-10, all of which could be part of the protective processes.

Topics: Animals; Cells, Cultured; Disease Models, Animal; Enterocolitis; Enzyme-Linked Immunosorbent Assay; Forkhead Transcription Factors; Gastrointestinal Tract; Homeodomain Proteins; Inflammation; Interferon-gamma; Interleukin-10; Interleukin-17; Interleukin-4; Intestinal Mucosa; Mice; Mice, Inbred C57BL; Mice, Knockout; Nematospiroides dubius; Ovalbumin; Strongylida Infections; T-Lymphocytes, Regulatory; Thy-1 Antigens

Intestinal autoimmune diseases are thought to be associated with a breakdown in tolerance, leading to mucosal lymphocyte activation perhaps as a result of encounter with bacterium-derived Ag. To study mucosal CD8(+) T cell activation, tolerance, and polarization of autoimmune reactivity to self-Ag, we developed a novel (Fabpl(4x at -132)-OVA) transgenic mouse model expressing a truncated form of OVA in intestinal epithelia of the terminal ileum and colon. We found that OVA-specific CD8(+) T cells were partially tolerant to intestinal epithelium-derived OVA, because oral infection with Listeria monocytogenes-encoding OVA did not elicit an endogenous OVA-specific MHC class I tetramer(+)CD8(+) T cell response and IFN-gamma-, IL-4-, and IL-5-secreting T cells were decreased in the Peyer's patches, mesenteric lymph nodes, and intestinal mucosa of transgenic mice. Adoptive transfer of OVA-specific CD8(+) (OT-I) T cells resulted in their preferential expansion in the Peyer's patches and mesenteric lymph nodes and subsequently in the epithelia and lamina propria but failed to cause mucosal inflammation. Thus, CFSE-labeled OT-I cells greatly proliferated in these tissues by 5 days posttransfer. Strikingly, OT-I cell-transferred Fabpl(4x at -132)-OVA transgenic mice underwent a transient weight loss and developed a CD8(+) T cell-mediated acute enterocolitis 5 days after oral L. monocytogenes-encoding OVA infection. These findings indicate that intestinal epithelium-derived "self-Ag" gains access to the mucosal immune system, leading to Ag-specific T cell activation and clonal deletion. However, when Ag is presented in the context of bacterial infection, the associated inflammatory signals drive Ag-specific CD8(+) T cells to mediate intestinal immunopathology.

Topics: Acute Disease; Administration, Oral; Adoptive Transfer; Amino Acid Sequence; Animals; Autoantigens; Carrier Proteins; CD8-Positive T-Lymphocytes; Cell Differentiation; Cell Line; Cell Movement; Cells, Cultured; Enterocolitis; Epitopes, T-Lymphocyte; Fatty Acid-Binding Proteins; Humans; Immune Tolerance; Immunity, Mucosal; Intestinal Mucosa; Listeria monocytogenes; Listeriosis; Lymph Nodes; Lymphocyte Activation; Mesentery; Mice; Mice, Inbred C57BL; Mice, Transgenic; Molecular Sequence Data; Ovalbumin; Peyer's Patches

Increased gastrointestinal absorption of intact antigen with systemic immunization has been considered a major etiologic factor in the development of food sensitivity. We attempted to test this hypothesis in infants with suspected food protein-induced entercolitis by measuring serum ovalbumin (OVA) concentrations after ingestion of egg white (prior to the performance of good challenges to establish this diagnosis). We first noted significant underestimation of serum OVA concentrations in the presence of even low serum anti-OVA antibody concentrations (greater than 1:12). Next, using selected noninhibitory sera, we found that all infants studied absorbed some OVA, there was no correlation between serum OVA levels and age (3-11 months), and there was no significant difference between serum OVA concentrations in infants who subsequently had positive oral food challenge responses (120 +/- 67 ng/ml) and a matched group with negative challenges (102 +/- 80). These data do not support the hypothesis that "intestinal closure" (antigen exclusion) occurs in the neonatal period or the role of antigen absorption as the major etiological factor in the development of food sensitivity. Better methods of quantitating macromolecular absorption must be developed before the role of antigen absorption in food sensitivity can be assessed. Of note, urinary excretion of intact OVA also occurred. This varied greatly from one voiding to the next and continuing for at least 13 hr after ingestion.

Topics: Antibodies; Antigens; Dietary Proteins; Enterocolitis; Female; Food Hypersensitivity; Humans; Immunization; Infant; Intestinal Absorption; Male; Ovalbumin

Stimulation ( [3H]thymidine incorporation) of blood lymphocytes cultured with food proteins was evaluated in infants with food protein-induced enterocolitis and correlated with the results of oral diagnostic challenges with the same foods (soy, cow's milk, and egg white). The geometric mean stimulation index for lymphocytes from patients with positive oral soy protein challenge that were cultured with soy protein was 8.5, and for patients with positive cow's milk challenge the stimulation index was 6.0 when casein was used in the cultures. Both values are significantly different from the values obtained from patients with negative oral challenges (p less than 0.01). The enhanced lymphocyte responses were specific for the food proteins responsible for clinical symptoms. It is not clear whether these lymphocyte responses are due to systemic immunization secondary to macromolecular absorption, or to an abnormality in immune regulation such as a delay in the development of oral tolerance mechanisms. They suggest, however, that circulating lymphocytes sensitive to the food antigens that produce the clinical symptoms are frequent in infants with this discrete form of food protein hypersensitivity.

Topics: Animals; Antigens; Cattle; Dose-Response Relationship, Immunologic; Enterocolitis; Food Hypersensitivity; Glycine max; Humans; Infant; Lymphocyte Activation; Lymphocytes; Milk; Milk Proteins; Ovalbumin; Plant Proteins, Dietary; Soybean Proteins