lecture 34 - adaptive immunity Flashcards
What is the first line of immune defence when pathogens enter the body via an injury?
Phagocytic cells (e.g. dendritic cells) break down pathogens.
What is antigen sampling/presentation?
A process in which dendritic cells break down antigens into peptides that they can present on their cell surface via MHC to T cells in the lymph nodes.
How are antigen peptides displayed to T cells?
Via MHC complexes on the surface of dendritic cells.
What is the function of CD4 T cells?
They help B cells make antibody. Help trigger CD8 memory and cytotoxic T cells
What is the function of CD8 T cells?
Become cytotoxic and kill virus infected cells (intracellular pathogens) and cancer cells.
How long ago did phagocytes evolve?
500 million years ago
What type of immunity do invertebrates have?
Innate immunity
What type of immunity do vertebrates have?
Innate and adaptive immunity
What is the process of peptide presentation using MHC-I?
Antigenic proteins break down antigens in the cytoplasm, these peptides are transported to the ER where they are loaded onto MHC-I then sent to the cell surface for immune surveillance.
What breaks down endogenous antigens into peptides?
Antigenic proteins
Where are endogenous antigens broken down into peptides?
The cytosol
Where does the loading of peptides onto MHC-I occur?
the Endoplasmic Reticulum.
What is the process of peptide presentation using MHC-II?
Exogenous antigens are absorbed by phagocytes and degraded into peptides and loaded onto MHC-II inside phagolysosomes. The complexes are then sent to the cell surface for immune surveillance.
Where are exogenous antigens broken down into peptides?
In phagolysosomes
How are cytotoxic T cells activated?
By binding to dendritic cells, recognising the antigen presented by MHC-I. (Then helped by CD4 helper T cell)
