GI immune system Flashcards
What are some kinds of Pattern Recognition Receptors?
Toll-like receptors (TLR’s), NOD-like receptoes (NLR’s), RigI-like receptors (RLR’s) C-type lectins (CLR’s), scavenger receptors
What are some kinds of antimicrobial peptides?
defensins, cathelin, protegrin, granulsyin, histatin, secretory leukoprotease inhibitor, and probiotics
What are some kinds of cytokines?
Autocrine, paracrine, endocrine cytokines that mediate host defense and inflammation, as well as recruit, direct, and regulate adaptive immune responses
What are pattern recognition receptors?
Inclusive term for antigen recognition receptor in innate system
Diversity of type BUT
Each immune cell carries identical receptor of a given type
Common theme is recognition of Pathogen-associated Molecular Patterns (PAMPs) but also Danger Associated Molecular Patterns (DAMP’s)
2 groups
Cell surface (transmembrane) and intracellular receptors – TLRs, NLRs, RLR’s and CLR’s
Fluid-phase soluble molecules
What is the role of macrophages?
Phagocytose and kill bacteria; produce antimicrobial peptides; bind (LPS); produce inflammatory cytokines
What is the role of plasmacytoid dentritic cells?
Produce large amounts of interferon- (IFN-) which has antitumor and antiviral activity, and are found in T cell zones of lymphoid organs; they circulate in blood.
What is the role of myeloid dendritic cells?
Interstitial DCs are strong producers of IL-12 and IL-10 and are located in T cell zones of lymphoid organs, circulate in blood, and are present in the interstices of the lung, heart, and kidney; Langerhans DCs are strong producers of IL-12; are located in T cell zones of lymph nodes, skin epithelia, and the thymic medulla; and circulate in blood
What is the role of natural killer cells?
Kill foreign and host cells that have low levels of MHC+ self peptides. Express NK receptors that inhibit NK function in the presence of high expression of self-MHC
What is the role of NK-T cells?
Lymphocytes with both T cell and NK surface markers that recognize lipid antigens of intracellular bacteria such as M. tuberculosis by CD1 molecules and kill host cells infected with intracellular bacteria.
What is the role of neutrophils
Phagocytose and kill bacteria, produce antimicrobial peptides
What is the role of eosinophils?
Kill invading parasites
What is the role of mast cells and basophils?
Release TNF-, IL-6, IFN- in response to a variety of bacterial PAMPs
What is the role of epithelial cells in innate immunity?
Produce anti-microbial peptides; tissue specific epithelia produce mediator of local innate immunity, e.g. lung epithelial cells produce surfactant proteins (proteins within the collectin family) that bind and promote clearance of lung invading microbes
What are the main features of the adaptive immune response?
Evolution in response to changing pathogen structures
Variable regions of pathogen that MUTATE at greater speed than humans
Central feature is UNIQUE antigen receptor found on each lymphocyte
In response to infection this lymphocyte undergoes CLONAL expansion
High degree of specificity
