Flashcards
Adaptive Immunity
Cards in this deck (26)
- 1What are TCR receptors on T cells-recognize fragments of digested antigen (peptides) 'displayed' on the surface of other cells. These peptides are presented on the cell surface in association w/ specialist molecules, known as the major histocompatibility complex (MHC)
- 2What is the MHC class I pathway-protein antigens (mostly viral) in the CYTOPLASM are digested to peptide fragments--> transported to the endoplasmic reticulum --> new MHC molecules synthesized --> transported to the cell surface to allow recognition by CD8 T cells
---all nucleated cells express MHC class I - 3What is the MHC class II pathway-protein antigens in the TISSUE FLUID (mostly bacterial antigens) are eaten by specialist phagocytic cells
--> lysosomes fuse w/ phagosome --> releasing acid hydrolases --> proteins digested into fragments --> MHC molecules are synthesized which travel via the Golgi to meet up with this endocytic pathway--> peptides loaded onto empty MHC class II molecules --> MHC class II peptide complexes are transported to the cell surface to allow recongition by CD4 T cells. - 4What cells have MHC II expression-dendritic cells, macrophages, B cells -- only the specialist antigen presenting cells
- 5What happens when a T cell recognizes an antigen when on surveillance mode-stops circulating and starts to proliferate - this is called the clonal expansion phase
- 6What does CD4 T helper type 1 do-helps macrophages kill bacteria (pathogen in the vesicles)
- 7What does CD4 T helper type 2 do-help the B cells make antibody (pathogen i in the tissue fluid)
- 8How do the CD8 killer cells kill cells-virus proteins processed via the MHC class I pathway -- they are expressed on the cell surface and 'mark' them as infected
-The MHC class I peptide complex now can be recognized by a CD8 killer cell which forces the infected cell to commit suicide -- via the Caspase cascade - b/f viral replication is complete - 9what are the 3 ways that apoptosis can occur-release of perforin and granzymes
-stimulation of apotosis via Fas/Fas-ligand interaction
-production of cytotoxic cytokines - 10How do TH-1 cells interact w/ macrophages and what do they secrete to activate macrophagesrespond via MHC Class II presentation of antigen, detected by the TCR. These effector T cells respond by secreting cytokines (interferon, gamma, IFN gamma) that activate the macrophages
- 11How does interferon gamma affect macrophage function-stimulates respiratory burst
-increased production and fusion of lysosomes w/ endosomes -- can digest more endogenous pathogens - 12How do B cells interact w/ TH-2 cellsvia MHC class II peptide: TCR engagement
- 13How do CD4 TH-2 cells activate B cells-interleukin 4 - stimulates them to grow into plasma cells that can secrete antibodies
- 14What else can cytokines which are produced by the TH-2 cells doinfluence what type of antibody the B cell will make Eg. IgG vs IgA vs IgE
- 15Which cells need to have the antigen to be processed b/f it can be presented to themT cells
- 16which cells can recognize the whole antigen without any initial processingB cells
- 17Why are B cells able to recognize whole antigen on the surface of pathogensb/c they can express surface immunoglobin (Ig)
- 18what is a plasma cell's main purposeto secrete loads of antibodies
- 19what does IgM do-first antibody to be produced
-this type of antibody functions to neutralize viruses, agglutinate bacteria and is a potent trigger of the complement cascade upon binding to microbial antigen - 20What is a class switch and what cells are involved-B cells can switch the type of antibody they produce with T cell help
-can switch from IgM to IgG
-further cytokine signals can modify thiss antibody response in favour of IgA or IgE - 21what does IgG do-it is a potent virus neutralizing antibody and can also trigger complement activation
-additionally IgG acts as an opsonin and can enhance phagocytosis of bacteria by macrophages and neutrophils expressing Fc-gamma receptors - 22Where does IgA come from-plasma cells in the MALT
- 23What does IgA do-binds to pathogens or toxins, preventing their harmful effects on epithelial cells
-now pathogens can't attach and infect via the mucosal route - 24When is IgE produced-during a parasite infection
- 25How does IgE work against parasites-adsorbed onto the surface of mast cells - which express specific Fc-epsilon receptors
-coating their surface with IgE enables these cells to bind to parasites more effectively, triggering degranulation and histamine release - 26What is a common cause of allergies-abnormal production of IgE to environmental antigens
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- Immunology Flashcards on Adaptive Immunity , created by Erin Loogman on 02/06/2018.
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- Erin Loogman
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