Ex 1: Immunology 2 Innate immunity Flashcards
What allows for some specificity for the innate immune system?
- structures shared by classes of microbes (PAMPs)
- damaged cells (DAMPs)
What allows for specificty for the adaptive immune system?
structural detail of microbial molecules (antigens)
Where are the receptors encoded for the innate immune system?
encoded in germline (limited diversity)
Where are the receptors encoded for the adaptive immune system?
encoded by genes produced by somatic recombination of gene segments (greater diversity)
What are the two principle types of reaction of the innate immune system?
- stimulate acute inflammation
- anti-viral defenses
What is the stimulation of acute inflammation response?
the accumulation of leukocytes, phagocytic cells, plasma proteins, and fluid derived from the blood at an extravascular tissue site of infection or injury
What are anti-viral defenses mediated by?
- NK cell-mediated killing of virus-infected cells.
- Interferon α/β (Type I interferons), which aresecreted by virus-infected cells, bind to receptors on surrounding cells, and induce an anti-viral state in those cells.
What are the prominent cell-associated pattern recognition receptors in the innate immunity?
Toll-Like Receptors (TLRs)
NOD-like Receptors (NLRs)
RIG-like Receptors (RLRs)
Where are the prominent cell-associated pattern recognition receptors in the innate immunity located in the cell?
extracellular
endosomal
cytosolic
What is the function of the toll-like receptors (TLRs)?
- acute inflammation
- stimulation of adaptive immunity
- antiviral state
What is the process of signaling through the toll-like receptors (TLRs)?
- reruitment of adaptor proteins
- activation of transcription factors
- increased expression of cytokines, adhesion molecules and production of type 1 interferon
What do nod-like receptors (NLRs) do?
recognize PAMPs and DAMPs in the cytoplasm and recruit other proteins to form signaling complexes (such as inflammasomes) that promote inflammation
What do RIG-like receptors (RLRs) do?
RLRs are cytosolic sensors of viral RNA that respond to viral nucleic acids by inducing production of the antiviral type I interferons
What are the parts of the epithelial barriers in the innate immune response?
- physical barrier to infection
- locally produced antibiotics
- intraepithelial lymphocytes
What are the two types of phagocytes?
- neutrophils
- monocytes/macrophages
What are neutrophils?
- Circulating phagocytic cells; Most abundant leukocytes blood.
- First cell type to respond to most infections
- Live only a few hours in tissues
What are monocytes/macrophages?
- Secrete cytokines that induce inflammation, and ingest and destroy microbes.
- Survive for long time periods in
tissues - Blood monocytes differentiate into tissue macrophages after entering tissues.
What are dendritic cells?
- Secrete cytokines
- Present antigenic peptides to T cells
What are mast cells?
- Abundant cytoplasmic granules.
- Present in skin and mucosal epithelium.
- contain vasoactive amines (e.g. histamine).
- cause vasodilation and capillary permeability
What cell type contains vasoactive animes and causes vasodilation and capillaqry permeability?
mast cells
What are innate lymphoid cells?
lymphocyte-like cells
- produce cytokines but lack T cells antigen receptors (TCRs)
What is the complement systems function?
Induce inflammation, opsonize microbes enhancing their phagocytosis, cause osmotic lysis of microbes
What are the three pathways of the complement system?
- classical pathway
- alternative pathway
- lectin pathway
What are the early/late steps of the complement system that all pathways have in common?
C3a: inflammation
C3b: opsonization and phagocytosis
C5a: inflammation
C6-9: lysis of microbe
