Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off
Reading...
Front

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key

image

Play button

image

Play button

image

Progress

1/18

Click to flip

18 Cards in this Set

  • Front
  • Back
Describe class 1 MHC genes.
encode glycoproteins found on the surface of all nucleated cells

presents Ags to CD8/cytotoxic T cells
Describe class II MHC genes.
Encodes glycoproteins on APCs

presents processed Ag to CD4/T helper cells
Describe class III MHC genes.
encode various secreted proteins that have immune functions
How are class I MHC molecules organized?
into A, B, and C regions
How are class II MHC molecules organized?
DP, DQ, DR arranged in pairs endcoding alpha and beta chains
MHC is a collection of genes on which chromosome?
chromosome 6
The set of MHC genes inherited from each parent is called what?
haplotype
Compare the structure of Class I and Class II molecules.
Class I - alpha chain with 3 domains, beta-2 microglobulin; deep socket

Class II - two nonidentical chains, 2 alpha and 2 beta domains; open pocket
Each individual can only express how many different class I molecules and class II molecules?
class I - 6 different molecules

class II - 12 different molecules
The highest levels of MHC I are found on what and the lowest levels are found on what?
highest - lymphocytes

lowest - neural cells
(fibroblasts, muscle cells, hepatocytes also express low levels)
What are TAP proteins required for?
loading of peptides (processed Ags) into the cleft of MHC molecules
What does a RR = 1 mean?
optimal - HLA expression occurs with the same frequency in the patient and general pop'n
What is self-MHC restriction?
CD4 and CD8 T cells can only recognize Ag when coupled with a self-MHC molecule
What cells are considered professional APCs?
dendritic cells, B cells, macrophages
The cytosolic pathway processes what type of Ags and is presented by what MHC class?
endogenous

MHC I
The endocytic pathway processes what type of Ags and is presented on what MHC class?
exogenous Ag

MHC II
Describe MHC I peptide processing.
1. endogenous Ag (viral or cancer protein) is degraded into a proteasome
2. the resulting peptides are transported by TAP to rough ER
3. alpha and beta-2 microglobulin are made in rough ER
4. Class I MHC alpha chain binds calnexin (chaperone), then beta-2 microglobulin. Calnexin disassociates, Calreticulin and Tapasin bind. MHC caputures peptide, chaperones disassociate
5. Class I MHC-peptide is transported from RER to golgi to plamsa membrane
Describe MHC II peptide processing.
1. Class II MHC alpha and beta bind invariant chain, blocking the binding of endogenous Ag
2. MHC complex is routed through golgi to endocytic pathway compartments
3. Invariant chain is degraded, leaving CLIP fragment
4. Exogenous Ag is taken up, degraded through endosome, endolysosome, and lysosome, and routed to endocytic pathway compartments
5. HLA-DM mediates exchange of CLIP for antigenic peptide
6. Class II MHC-peptide is transported to plasma membrane