Immune System Flashcards
Lymphocytes
What type of cell are lymphocytes?
Found in what organs?
Where do they originate?
WBC/leukocyte
Found mainly in lymphatic organs
Originate in the bone marrow
Lymphocytes
Where do T-cells mature?
What about B- cells?
Thymus
Bone Marrow
Lymphocytes
What are the 3 classes of lymphocytes?
3 classes: T cells, B cells, NK cells
Innate Immune System
What is the innate immune system?
What type of response does it generate?
First line of defense
Generates a nonspecific immune response (generalized)
Innate Immune System
What are the 2 parts of innate immunity?
External immunity
Internal immunity
Innate Immune System
External immunity
Physical/physiological barriers preventing pathogen entry
Barriers include skin, mucous membranes, and chemical secretions.
Innate Immune System
Internal immunity
What is it composed of?
Internal defenses to neutralize pathogens that have entered
Composed of inflammatory response, complement proteins, phagocytic and NK cells.
Innate Immune System
What is the first layer of innate immunity?
The outer walls of our body like the skin, cilia, stomach acid and symbiotic bacteria
Innate Immune System
Within the skin, what is the important enzyme used to break down bacterial cell walls?
Lysozyme is used to break down bacterial cell walls
Sebum is a barrier that also has ________ properties.
antimicrobial
Inflammatory Responses
What is the leukocytes responsible for the first part of the immune response? What is this response called?
Mast cells
Rally signaling
Inflammatory Responses
If there is an injury, mast cells will release ______, which ______ blood vessels.
histamine, dilates
- this allows for more immune cells to be let into the tissues!
Inflammatory Responses
What are the 5 signs of inflammation?
SLIPR
swelling, loss of function, increased heat, pain, redness
Inflammatory Responses
_____ blood flow results in a ______ temperature.
increased, higher
Immune Cells and Molecules
Diapedesis is the process by which…?
Cells move from the capillaries to the tissues in order to fight pathogens
Immune Cells and Molecules
______ is the method by which cells move in response to a chemical signal.
Chemotaxis
Immune Cells and Molecules
Granulocytes are part of what immune system? What makes them special?
Innate immune system
WBC that has specific granules in their cytoplasm
Immune Cells and Molecules
How many types of granulocytes are there? Name them
4
Neutrophils
Eosinophils
Basophils
Mast cells.
Immune Cells and Molecules
List the 5 main types of leukocytes from highest to lowest in quantity
Never Let Monkeys Eat Bananas
- Neutrophils
- Lymphocytes
- Macrophages
- Eosinophils
- Basophils
Immune Cells and Molecules
Neutrophils
Phagocytes in innate immunity
First cells to be recruited to a site of inflammation
Immune Cells and Molecules
T/F: B cells, T cells, and natural killer cells are all part of innate immunity
FALSE, only NK cells are part of innate. B/T cells are part of adaptive immunity
Immune Cells and Molecules
NK Cells
What do they attack?
What 2 things do they use?
Attack virally-infected cells + cancerous cells
Use perforin (create holes) & granzyme (stimulate apoptosis) to lyse cells
B and T cells are part of _____ immunity and must be ______.
adaptive, activated
____ and ____ cells are the most common type of leukocyte found in _____.
B and T, lymph
Immune Cells and Molecules
Explain the similarities/difference between Macrophages and Monocytes
Both are phagocytes in innate immunity.
Monocytes are the immature form found in blood vessels
Macrophages are the mature form after diapedesis
Immune Cells and Molecules
What are the 2 phagocytes in innate immunity?
Macrophages and Neutrophils
Immune Cells and Molecules
What cells can also act as antigen-presenting cells to activate adaptive immunity
Monocytes/Macrophages and Dendritic cells
Immune Cells and Molecules
Eosinophils
What immunity is it part of?
What type of cell is it?
- Part of innate immunity
- Type of granulocyte
- Have granules that can be released to kill pathogens/parasites
Immune Cells and Molecules
Basophils
What 2 molecules do they contain?
Circulate how?
- Type of granulocyte
- Contains granules with histamine (vasodilation) and heparin (anticoagulant )
- Very similar to mast cells, but circulate as mature cells
Immune Cells and Molecules
Basophils circulate as ______ cells
Mast cells circulate as ______ cells
mature cells, immature cells
T/F: Dendritic cells are part of innate immunity
TRUE, can also be part of adaptive immunity if they act as APC though
What do dendritic cells use to scan tissues?
Pinocytosis (cell drinking) and phagocytosis (cell eating)
If dendritic cells act as antigen-presenting cells, where do they migrate to?
To the lymph nodes
Toll-like receptors
What cells utilize them? Why?
What happens when they bind?
Macrophages and dendritic cells
Recognize conserved parts of microbes
Binding to these receptors triggers phagocytosis & activates the innate immune system.
What cell regulate macrophages and dendritic cells? Innate or adaptive?
Platelets, innate
Interferons
Secreted by what?
Bind to what?
Secreted by virally-infected cells
Bind to non-infected cells to prepare them for a virus attack
_____ help activate dendritic cells.
Interferons
Complement System
What is the complement system? What cascade and activity helps?
- Group of appprox. 30 proteins aiding immune cells in fighting pathogens
- The complement cascade and protease activity
Complement System
Name the 3 complement protein actions
Opsonization: tags antigens for phagocytosis
Amplifies inflammatory response
Forms a membrane attack complex: holes in pathogens & lyses them
Adaptive Immunity
What is the adaptive immune system?
A specific immune response (targets specific antigens)
Adaptive Immunity
The ______ is the important part of the antigen that is recognized by the immune cell
epitope
Adaptive Immunity
What complex is used to recognize itself vs non-self? Where is it found?
Major histocompatibility complex (MHC) Found on the surface of cells
Adaptive Immunity
What is the surface molecule present on ALL nucleated cells? Is everyone’s the same?
MHC Class I
Each genetically different individual will have a different MHC I molecule
Adaptive Immunity
_______ diseases occur when the immune system attacks self MHC I.
Autoimmune
Adaptive Immunity
What is the surface molecule present on APCells? What is it used for?
MHC Class II
Used to present foreign antigens to activate immune cells
Adaptive Immunity: B cells
B cells control what kind of immunity? How?
Antibody-mediated immunity (humoral immunity)
By managing the production & release of antibodies
Adaptive Immunity: B cells
Can B-cells act as an APCell?
Yes
Adaptive Immunity: B cells
B cell receptors are located where?
What do they bind to? Are they unique?
B cell receptors (BCRs) are located on B cells
Bind to antigen epitopes either free-floating or on APCs. Each B cell has a unique BCR, so yes
Adaptive Immunity: B cells
Clonal selection model
What do B cells divide into?
Clonal expansion divides the B cells
Plasma cells (antibody-secreting cells) or memory B cells (to be activated later in case of another attack).
What are some antibodies functions?
ANTibodies
Activate the complement system
Neutralize the antigen by coating it
Tag antigens for phagocytosis
Antibodies are structurally identical to what?
How are they different though?
BCRs
BUT freely circulate in blood & lymph
Adaptive Immunity: B cells
Antibodies contain _____ chains and ____ chains that are linked together by _____ bonds.
light, heavy, disulfide
Variable region vs Constant region in antibodies
variable: recognizes different antigens
constant: the same for antibodies within the same class
Classes of Antibodies
lgM
present in a pentameric form and is the largest antibody. The first antibody to be produced; activates the complement system.
Classes of Antibodies
lgA
present in a dimeric form and found most abundantly in bodily secretions. Newborns receive passive immunity through breast milk containing IgA. Also, IgA mainly binds pathogens externally, outside of circulation.
Classes of Antibodies
lgE
monomer that is present on basophils and mast cells as antigen receptors. When bound to an allergen, it triggers histamine release and an allergic reaction. Think Ig sneEze.
Classes of Antibodies
lgD
monomer that we have very little information about. Only small amounts are produced.
Classes of Antibodies
lgG
monomer that is the most abundant antibody in circulation. Also the only antibody that can cross the placenta to give fetus passive immunity. Helps the complement system to cause opsonization (tags antigens and subsequent phagocytosis). Helps IgM activate the complement system.
Memory B cells survive for a ___ time and lay ____ until _____ by the same antigen that triggered the original clonal expansion.
long, dormant, reactivated
After reactivation, ___ ___ _____ cause massive ____ production.
memory B cells, antibody
What type of immunity do T-cells control? How?
Cell-mediated immunity
Directly acting on cells instead of sending antibodies out.
T/F: T cell receptors (TCRs) are not unique and do not undergo clonal selection
FALSE! they ARE unique and DO undergo clonal selection
T/F: T-cells must bind to antigens presented on APCs to be activated
TRUE!
How many types of antigens does 1 T cell bind to in order to be activated?
Binding only to ONE type of antigen per T cell
Antigen Presentation to T-cells
MHC I Presentation
T cells differentiate into CD8/CD8+ T cells (cytotoxic T cells), which directly kill infected cells through perforin (poke holes) and granzymes (cause apoptosis). However, T cells are different from natural killer cells because they are more specific and require antigen presentation.
Antigen Presentation to T-cells
MHC II Presentation
T cells differentiate into CD4 T cells (helper T cells), which release interleukins to boost both innate immunity and adaptive immunity. These interleukins help attract innate immune cells and increase proliferation of other T and B cells.
Interleukins
Signaling between immune cells; regulate immune cell activation
Active immunity is what?
Immunity an organism gains from being infected once already by a pathogen
Ex. vaccination introduces the antigen in deactivated state to stimulate active immunity, which induces memory B & T cell formation.
Passive immunity is what?
Immunity one organism gains from receiving the antibodies from another organism that already has that immunity.
Ex. fetus gains passive immunity through the placenta (IgG) while a newborn gains passive immunity through breast milk (IgA)
The fetus and newborn are referred to as ________ because they do not yet have their own _____ immunity.
immuno-naive, active
