Chapter 4 AI generated Flashcards
Describe the process of antigen presentation viaHC I molecules.
mRNA is translated into protein in the cytoplasm, peptides are loaded onto MHC I molecules in the ER, correct peptides are displayed on the cell surface.
What is the role of TAP1 and TAP2 in antigen presentation?
TAP1 and TAP2 transport short peptides across the ER membrane for loading onto MHC I molecules.
How are MHC II molecules loaded with peptides for antigen presentation?
MHC II molecules bind to invariant chain in the ER, then in endosomes, CLIP is released by HLA-DM to allow exogenous peptides to be loaded.
Define the function of proteasomes in antigen presentation.
Proteasomes degrade proteins into short peptides for loading onto MHC I molecules.
Describe the specificity of proteasomes in different cells like macrophages and liver cells.
Proteasomes in macrophages are regulated by cytokines and preferentially cut proteins after hydrophobic or basic amino acids, while in liver cells they degrade proteins more randomly.
What is the significance of HLA-DM in the process of antigen presentation via MHC II molecules?
HLA-DM catalyzes the release of CLIP, facilitating the loading of exogenous peptides onto MHC II molecules and aiding in peptide selection.
Describe the role of activated dendritic cells in the immune system.
Activated dendritic cells act as a bridge between the innate and adaptive immune systems. They can activate virgin T cells by recognizing molecular patterns of invaders using Toll-like receptors.
What is the function of activated macrophages in the immune response?
Activated macrophages can both present antigens to T cells and kill pathogens. They become efficient antigen-presenting cells after activation by cytokines or pattern-recognition signals.
Define the function of activated B cells in the immune system.
Activated B cells can concentrate antigens for presentation and become efficient antigen-presenting cells for Th cells. They rapidly increase levels of MHC II and B7 upon activation.
How do dendritic cells travel to lymph nodes after activation?
After activation, dendritic cells travel through the lymphatic system to the nearest lymph node, usually within a day. They carry a representative sample of antigens collected from the tissue.
Describe the importance of MHC I in the immune system.
MHC I molecules present antigens derived from intracellular pathogens to cytotoxic T cells. This is crucial for immune surveillance and elimination of infected cells.
Explain the significance of MHC II in the immune response.
MHC II molecules present antigens from extracellular pathogens to helper T cells. They play a key role in initiating and coordinating the adaptive immune response by ensuring T cells only recognize presented antigens for safety reasons.
