Unit 3 Lecture 17 Flashcards
Define immunity
the ability of an organism to resist a particular infection by the action of antibodies or WBCs
What are the two types of immunity within the immune system?
- Innate immunity
- Adaptive immunity
What is innate immunity?
Body’s lines of defense against invading pathogens
- non-specific things that the body does to fight all foreign things
What are the body’s lines of defense?
- physical barriers
- fever
- inflammation
- cells and chemicals
What is adaptive immunity?
Body’s ability to recognize and defeat invading agents (bacteria, viruses, and foreign stuff)
How do you distinguish adaptive immunity from innate immunity?
- SPECIFICITY for particular foreign antigens and TOLERANCE for self proteins
- MEMORY of foreign antigens encountered in the past to fight again
What are cell proteins really made out of?
gene codes of amino acids
What is special about amino acids > or equal to 8 in length?
human and bacterial protein sequences can be distinguished from each other
What are landmines for molecular information?
residual bodies
What are residual bodies?
During phagocytosis, its the product of phagosomoes being broken down by lysosomes
What information do residual bodies give us?
- info about things present in extracellular fluid
2. if something destroyed was foreign
What proteins are found on the body of antigens that ID the different viruses in the body?
MHC I and II proteins
What do MHC proteins do?
“displays” information in the form of peptides to the immune system
What does the MHC I protein look like?
tongs holding a ball
What dos the MHC II protein look like?
Worms w a diamond in the middle
What do MHC I and II proteins present?
processed antigens to the cells of the immune system
Where are the presented antigens from in MHC II?
protein components of materials engulfed and digested by phagocytes
More specifically, MHC II displays what type of antigen?
extracellular antigens
Where are the presented antigens from MHC I from?
randomly sampled proteins inside the cell
More specifically, MHC I displays what type of antigen?
Intracellular antigens
What is one type of cell that interacts with MHC II presented antigens?
Helper T cells CD4
What is one type of cell that interacts with MHC I presented antigens?
Cytotoxic T cells CD8
How does the body tell what is inside of a cell?
Random Sampling
*nucleated cells randomly sample the proteins in its cytoplasm
Where are MHC I and II proteins synthesized in the cell?
Endoplasmic reticulum
What must all nucleated cells do?
Present their antigens via MHC I
What happens to cells that do not present their antigens?
cell is killed by NK cells
What is the only tool that can inspect MHC I presented antigens?
T cell receptors of a T cell
What is the purpose of the T cell receptor?
It tells a T cell is the antigen presented belongs to the organism or if it is another organisms
How is every T cell born with a unique T cell receptor (TCR)?
Genetic recombination
Where does antigen presentation and recognition occur?
Thymus
Where do lymphocytes ( B cells and T cells) originate?
Red bone marrow
Where do B cells mature?
Red blood marrow
Where do T cells mature?
Thymus
How to T cells mature?
Under positive and negative selection pressures
What is negative selection?
eliminates T cells that are strongly anti-self
What is positive selection?
selects T cells with a weak response to self-antigens -> immunocompetent and self-tolerant
What conditions allow T cells to live?
- Can recognize self-MHC proteins (positive selection)
- Can’t recognize self-peptides (negative selection)
What happens under any other condition for T cells?
T cell dies
