The intestinal epithelial cell: processing and presentation of antigen to the mucosal immune system
ABSTRACT The immunologic tone of the intestinal tract is one of suppressed or highly regulated responses. While there are several components (intrinsic and extrinsic to the gut-associated lymphoid tissue) responsible for this immunologically suppressed tone, the intestinal epithelial call (IEC) has been proposed as a key player in this process. IECs can take up and process antigen but distinct surface molecules and restriction elements allow them to present these antigens to unique regulatory T cells. These include the expression of the class Ib molecule CD1d as well as a novel CD8 ligand, gp180. These molecules come together to activate a subpopulation of CD8+ regulatory cells whose function is to suppress immune responses in an antigen non-specific fashion most likely through cognate interactions. This form of regulation may be unique to the gut-associated lymphoid tissue which is consistent with the unusual demands upon this part of the immune system.
- SourceAvailable from: Carolina Maldonado Galdeano[Show abstract] [Hide abstract]
ABSTRACT: Health claims of lactic acid bacteria (LAB) used in functional foods and pharmaceutical preparations are based on the capacity of these microorganisms to stimulate the host immune system. In this study, the antigenic effect of LAB (Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus) on the gut immune system of BALB/c mice was evaluated. A dose-dependent increase of the Bcl2 protein was observed with all LAB assayed. Furthermore, the analysis of cytokine-producing cells in the lamina propria of gut showed that TNFalpha and INFgamma values, determined in macrophages cultured from Peyer patches, were enhanced for all the LAB assayed. An important increase of interleukins IL-10 and IL-4 was observed mainly in mice fed with Lactobacillus delbrueckii ssp. bulgaricus or Lactobacillus casei, while a significant induction of IL-2 and IL-12 was only observed with L. acidophilus (P<0.01). These effects were dose dependent. The role of produced cytokines in the balance Th1/Th2 was determined by a systemic antibody response against parenterally injected ovoalbumin. L. casei, L. delbrueckii ssp. bulgaricus and L. acidophilus enhanced the IgG1 response favouring Th2 balance, while L. acidophilus also increased the IgG2a response inducing Th1 balance. S. thermophilus did not influence the balance Th1/Th2. Our studies showed that lactic acid bacteria induce distinct mucosal cytokine profiles showing different adjuvant capacity among them. Thus, selection of probiotic strain with immunological properties must be well defined to influence cytokine expression that favour the claimed immune response.European Journal of Clinical Nutrition 12/2002; 56 Suppl 4:S21-6. DOI:10.1038/sj.ejcn.1601658 · 2.95 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Linköping 2007 Dnr LiU 63/07-14 (10) Hälsouniversitetet sv/eng Dessa logotyper och sigill finns i blått, svart och negativ (vit) text.
- [Show abstract] [Hide abstract]
ABSTRACT: Extremely complex interactions exist between the components of intestinal ecology, including the host intestinal anatomy, intestinal microbial populations, and the nutrition of the animal. The anatomical regions of the gastrointestinal tract can be characterized based on cell type and function and include the epithelial cell layer, lamina propria, muscularis, widespread components of the immune system, and mucus layer. The microflora consists primarily of bacteria, which can be broadly categorized as harmful and commensal populations. Harmful populations may be involved in the induction of infection, intestinal putrefaction, and toxin production. Commensal populations may be involved in vitamin production, stimulation of the immune system via nonpathogenic means, and inhibition of harmful bacterial populations. The nutrition of an animal can directly and indirectly affect each of the aforementioned components and, thus, dramatically affect the health and performance of production animals. A comprehensive understanding of these interactions will provide tools by which animal health and performance can be maximized while the use of pharmacological agents and the excretion of nutrients can be minimized.The Journal of Applied Poultry Research 03/2006; 15:161-173. DOI:10.1093/japr/15.1.161 · 0.59 Impact Factor