Immune System Flashcards
What is innate immunity?
generalized immunity with non-specific defense mechanisms
What are the three levels of innate immunity?
- physical and chemical barriers
- innate inflammatory response
- innate immune cells
What else can innate immunity activate?
adaptive immunity
What is an advantage and disadvantage of innate immunity?
it is fast but it doesn’t remember past infections
What is the skin barrier in the innate immune system?
-sweat is antimicrobial and has lysozymes
-and you are covered in “good” bacteria and fungi
What is the digestive, respiratory, and urogenital tracts barriers?
-secretory cells produce mucus to trap and destroy pathogens
-saliva has lysozymes that destroy pathogens
-tears and urine flush out pathogens
-low stomach pH kills pathogens
What happens when we couldn’t keep the
pathogen outside of the skin?
then we can use innate immune cell receptors
What are some innate immune cells?
mast cells, neutrophills
How do the cells recognize the pathogens?
they recognize general pathogen parts (such as single strand DNA, bacterial membrane)
What do innate immune cells do when they find a pathogen?
they trigger a transduction pathway
What does the transduction pathway of innate immune cells release?
complement
What is complement?
-poking holes in the pathogens to send signals of apoptosis
Explain the cascade of inflammatory response?
- injured cells secrete histamines (crying out for help)
- blood vessels dilate (let more blood in) -causes area of infection to be hot and red
- histamines make capillaries more permeable (easy for immune cells to get in) -causes swelling and pain
- neutrophils eneter permeable capillaries
What happens when neutrophils enter permeable capillaries?
- they recruit monocytes (which mature into macrophages)
- macrophages releases interleukin 1
What are monocytes?
immature macrophages that mature when they are needed
What does interleukin do, and what is the side effect?
they actually store iron in the spleen, because bacteria need iron to grow (this causes a fever)
What is adaptive immunity?
memory immunity that recognizes specific pathogens
What is an antigen?
something the body recognizes as non-self
What are two types of adaptive immunity?
- cell mediated
- humoral
What is a cytotoxic T-cell?
a white blood cell that has the ability to kill infected cells in the body
What type of adaptive immunity is the cytotoxic t-cell a part of?
cell mediated
How does a cytotoxic t-cell kill infected cells?
-it releases perforin which creates holes in the infected cell signaling apoptosis
How do we activate cytotoxic t-cells?
an infected cell will present that it has been activated on its cellular membrane
What is another way of activating cytotoxic t-cells?
- if a macrophage has been eating the infecting cells then the antigen of the infected cell will be displayed on the macrophages surface
- a helper t-cell is now activated and binds to the macrophage
- the helper t-cell signals the n cytotoxic t-cells
When a cytotoxic t-cell is activated, does it only kill the pathogen?
no, it actually divides to make cytotoxic t-cells and memory cytotoxic t-cells which help remember the infection for next time
Are helper-t-cells only involved in the cell-mediated response?
nope, they are also involved in the humoral response
What is the humoral response?
a response that involved b-cells and helper t-cells
What happens during the humoral response?
- macrophage eats infected cell
- macrophage presents the antigen on its surface
- helper t-cell binds to macrophage and sends signal to b (beta) cells
- beta cells produce antibodies
What are antibodies?
proteins that can bind to an antigen and hinder its ability to function
Are antigens specific?
yes, antigens are very specific and can only bind to specific pathogens
Do b-cells only produce antibodies?
nope, they clone themselves and produce memory beta cells which keep a memory to the antigen and pathogen they destroyed
What are plasma b-cells?
b cells that produce antibodies
What are MHC proteins?
proteins that bind peptide fragments of the pathogen and display on the cell surface
What are MHC proteins 1?
-proteins that is found in every nucleated cell
What do MHC 1 proteins activate?
cytotoxic t-cells
What are MHC 2 proteins?
-proteins that is found in macrophages that ingested the infected cells
What do MHC 2 proteins activate?
helper t-cells
Can b cells be antigen presenting cells?
yes, the antigen can directly bind to b cells and b cells then act as APC
What happens when a helper t-cell recognizes antigens on b cells?
it triggers a humoral response
What happens when a helper t-cell recognizes antigens (MHC II) on macrophages?
trigger cytotoxic t-cells and a cell mediated response
How does HIV affect helper t-cells?
-it attacks the helper t-cells directly
-helper t-cells then die because the virus will replicate using the t-cells nucleus
-this causes there to be no +director of communications” for the immune system
-this leads the immune system to be more vulnerable
What do the lymphoid organs do?
they support innate and adaptive responses by producing and maturing white blood cells
What are primary lymphoid organs?
organs that make and mature immune cells
What organ makes both b and t cells?
bone marrow
Where do b cells mature?
bone marrow
Where do t-cells mature?
thymus
What is maturation?
white blood cells get trained to not recognize self cells (so that your own body doesn’t attack you)
What are secondary lymphoid organs?
where mature lymphocytes go to search for targets
What are some secondary lymph organs?
lymph nodes, spleen, tonsils, appendix
What does a naive cell mean?
unactivated cells
What is a lymphocyte?
white blood cells
What are the 3 APC?
dendritic cells, macrophages, and b cells
