Flashcards in Innate Immunity - Sentinel Cells Deck (62):
Sentinel or surveillance cells are concentrated where? Why are they concentrated here?
Peripheral tissues where they can come into immediate contact with invading microbes or foreign particles
How to sentinel cells initially discriminate self from non-self?
What are 5 types of sentinel cells?
Dendritic cells, macrophages, mast cells, eiosinophils and epithelial cells
Dendritic cells present peptide antigens to?
Naive T cells
Dendritic cells direct the immune response via?
Cell-to-cell receptor communication and the secretion of cytokines
Very briefly list the 7 functions of macrophages
Act as sentinel cells, innate effector cells carrying out phagocytosis, act as APCs for memory T cells, effector cells for CMIR, nutrient recycling by phagocytizing dying cells, regulate inflammation, participate in the resolution phase producing products which aids in tissue remodeling and repair
Sentinel cell types except for epithelial cells, are largely derived from?
Bone marrow equivalent tissues
Differentiation of cells from pluripotent stem cells
What directs sentinel cells to their constitutive and inductive trafficking to peripheral tissues?
What three sentinel cells are part of the mononuclear phagocytizic system (MPS)?
DCs, monocytes and macrophages
The majority of the cells in the mononuclear phagocytic system originate from hematopoietic stem cells that differentiate into?
Common macrophage and DC progenitors (CMDP)
CMDP give rise to either __________ or monocytes that migrate into tissues and mature into macrophages
Common DC progenitors (CDP)
Mast cells are found where?
In the skin an at mucosal surfaces
Mast cells can elicit _________ and ______ effects very rapidly via PRE ligation with PAMPs/alarmins and subsequent ____________.
Systemic, local, degranulation
Mast cell are motile cells that act as an important effector during what type of infection?
Mast cells are key mediators of?
Antibody-mediated atopic hypersensitivity reactions
Normally, mast cells undergo what type of degranulation?
In cases of anaphylaxis, mast cells undergo what type of degranulation?
What is spontaneous degranulation of mast cells?
All of their granular contents are released into the surrounding tissues causing immediate and severe inflammation
What is present in the granular contents of mast cells?
Vasoactive compounds, pro-inflammatory cytokines, Chemokines, chemo attractants and anti microbial enzymes & peptides
Mast cells have the capacity to undergo an alternative death pathway referred to as?
What occurs during netosis?
Mitochondrial and genomic DNA, just ones, and granule proteins are released from the cell forming antimocrobial extracellular traps
True or false - mast cells are also involved in the acquired immune response
Mast cells contain what receptor which bids to immunoglobulin IgE?
What occurs when a mast cell comes into contact with a specific antigen in response to IgE cross linking with the antigen?
Chicken mast cells are activated by? And are responsible for?
IgY and responsible for local anaphylactic reaction in the gut
The cross-linking of two FCeRs activated several?
Tyrosine kinases leading to the activation of phospholipase C
What does phospholipase C do?
Splits membrane phosphotidylinositol 4,5- biphosphate (PIP2) into messenger molecules diacylgycerol (DAG) and inositol tri phosphate (ITP)
What does ITP do?
Increases intracellular calcium release from storage sites
What triggers granule mobilization and transcription of cytokines as well as COX and LOX?
Protein kinases activated by DAG and calcium
What does phospholipase A do and how is it activated?
Activated by IgE cross-linking and it acts of cell membrane phospholipids to produce Arachnidonic acid (AA)
What is AA converted to by LOX and COX enzymes?
Vasoactive eicosanoid lipids
What enzymes are produced by LOX and COX?
LOX = leukotrienes
COX = prostaglandins
What are the two major types of mast cells?
Connective tissue mast cells and mucosal mast cells
Where are CTMCs found?
Peritoneal cavity and skin
Where are MMCs found?
Intestines and lungs
What do CTMCs contain?
What do MMS contain?
Proteoglycan chondroitin sulfate
How are MMCs different then CTMCs?
Smaller in size, contain less histamine, shorter life span
True or false - mast cells can degranulation in response to PAMPs and alarmins
What are the two major neuro peptide receptors mast cells express?
Alpha and beta adrenoreceptors (ADR)
What is norepinephrine and what does it do?
It's an alpha ADR agonist or beta ADR antagonist and it enhances mast cell degranulation
What is epinephrine and what does it do?
It's a beta ADR agonist or an alpha ADR antagonist and it inhibits mast cell degranulation
What is the function of eosinophils?
Regulate inflammation, maintain epithelial barrier function at mucosal surfaces
Excessive eosinophilia is associated with?
Eosinophil differentiation requires the presence of?
Eosinophils are recruited to tissues and become activated by?
IL-33 and IL-5
What are IL33 and IL5 produced from?
Th2 cells and by mast cell degranulation products
What is present in mast cell degranulation products?
Eotaxin, histamine, leukotriene B4 (LTB4), serotonin, and platelet activation factor (PAF)
What can eosinophils do during an acquired immune response?
Phagocytosis and act as antigen presenting cells
Eosinophils express __ receptors which means they can undergo _________ degranulation
True or false - extracellular traps are produced by mast cells and eosinophils
What do extracellular traps do?
Immobilize and neutralize bacteria
What are the two main constituents of eosinophil granules?
Cationic proteins and various RNases
What are the cationic proteins?
Major basic protein (MBP) and eosinophil peroxidase (EPO)
How do MBP and EPO work?
They bind to helminths or bacteria. Their positive charge disrupts the membrane lipid bilateral affecting membrane permeability leading to cytotoxicity.
Eosinophils involved in tissue repair are an important source of?
Matrix metalloproteins (MMPs)
What do MMPs do?
Degrade extracellular matrix materials such as collagen enabling inflammatory cells to migrate through tissues and therefore allows for tissue reorganization to occur during healing
What is TGF-beta produced from and what does it do?
Produced from eosinophils and promotes differentiation and proliferation of fibroblasts, epithelial cells and smooth muscle cells during tissue healing
What are IL-6, IL-8, TGF-beta and vascular endothelial cell growth factor examples of?
Pro-angiogenic factors from eosinophils
What are thrombospondin and endosatin examples of?