Term
| What are the three defenses against pathogens? |
|
Definition
-physical barriers
-innate immunity
-adaptive immunity |
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Term
| Compare the relative size of mucosa and skin. Why is this relavent? |
|
Definition
-mucosa comprises 400 sq m
-skin is 2 sq m
-thus this is where pathogens enter |
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Term
| What are the 3 direct functions of innate immunity? |
|
Definition
-induce cytokine secretion and inflammation: activated macrophages alert immune system via secretion of cytokins
-destroy extracellular pathogens: phagocytosis (neutrophils/macrophages) or lysis (complements)
-destroy intracellular pathogens: apoptosis via natural killer cells |
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Term
| Compare/contrast innate and adaptive immunity |
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Definition
-innate immunity comes at birth without memory and does phagocytosis/lysis
-adaptive immunity: comes from memoryand causes apoptosis |
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Term
| True or False: The innate immune system directs the adaptive immune system. |
|
Definition
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Term
| What are the 2 divisions of adaptive immunity? |
|
Definition
-Humoral immunity via B-cells: antibodies
-Cell-mediated immunity (CMI) via T-cells: cytotoxic lymphocytes kill virus infected cells directly OR T-helper cells "activate" immune cells via secretion of Cytokines |
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Term
| What is the main function of neutrophils and macrophages? Which is more important regarding this function? |
|
Definition
-kill pathogens by phagocytosis
-NEUTROPHILS ARE FAR MORE IMPORTANT IN PHAGOCYTOSIS |
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Term
| Briefly describe the process of phagocytosis. |
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Definition
| -phagocytes extend pseudopods that reach out, grab, and pull in pathogens for phagocytosis |
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Term
| Why is opsonization important? |
|
Definition
| -it enhances phagocytosis |
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Term
|
Definition
| -like dipping a French fry/bacteria into ketchup/Ab or complement proteins that increases the rate of phagocytosis |
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Term
|
Definition
| -cytoplasmic vesicle that engulf pathogens after phagocytosis |
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Term
| What is the difference b/n lysosomes and phagolysosomes? |
|
Definition
-lysosomes are pockets of enzymes inside cells
-phagolysosomes are lysosomes that have fused with phagocytosed material to kill the pathogens |
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Term
| Lysosomes contain many enzymes, most importantly _______. Define the blank. |
|
Definition
-acid hydrolases
-hydrolyze and break down covalent: ex: lysozyme, lipases, proteases |
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Term
| After phagocytosis, lysosomes fuse with _________ to form _________, in which pathogens are digested and destroyed. |
|
Definition
-phagosomes
-phagolysosomes |
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Term
| Where do neutrophils originate? |
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Definition
|
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Term
| Describe the half-life of neutrophils. |
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Definition
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Term
| The majority of the time, where are neutrophils located? When does this change? |
|
Definition
-in the blood stream
-enter tissues IFF there is an infection |
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Term
| What signals neutrophils to enter tissues in the case of an infection? |
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Definition
|
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Term
| What happens to neutrophils once the phagocytose pathogens (primarily bacteria)? |
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Definition
| -once neutrophils leave the blood vessels, they never return, they die in tissues |
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Term
|
Definition
| -Pattern Recognition Receptors |
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Term
| What does TLR stand for? What is it an example of? |
|
Definition
-Toll-like receptors
-ex of pattern recognition receptors (PRR) |
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|
Term
|
Definition
-pathogen-associated molecular pattern
-the pathogen structural molecules recognized by PRRs |
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Term
| _______ are by far the most important component of the innate immune system. |
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Definition
|
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Term
What is the specialized name for macrophages in the following tissues:
a) liver
b) lungs
c) connective tissue
d) brain |
|
Definition
a) Kupffer cells
b) alveolar macrophage
c) histiocytes
d) microglial cells |
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Term
| What are the 3 functions of macrophages? |
|
Definition
-secrete cytokines to alert and attract other immune cells to the area of infection
-phagocytize and kill pathogens
-macrophages also present parts of the broken down pathogens to other immune cells: act as antigen presenting cells |
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Term
| What does APC stand for? Example? |
|
Definition
-antigen presenting cells (APC)
-ex: macrophages |
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Term
| True or False: Similar to neutrophils, macrophages die after activation. |
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Definition
| FALSE, they return to resting state |
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Term
| What are cytokines and what do they do? |
|
Definition
-small hormone-like molecules secreted by a variety of immune cells including macrophages
-they bind to receptors on other immune cells thereby regulating their function: they allow immune cells to talk to each other |
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Term
| Describe the function of Natural Killer cells |
|
Definition
| -they hunt for and recognize "abnormal" (stressed, infected, or transformed) and KILLS them |
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Term
|
Definition
| -they secrete molecules that bind to death proteins in the celld, inducing programmed cell death/apoptosis |
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Term
| What is Perforin? What cells use it? |
|
Definition
-perforin is a pore-forming enzyme
-NK cells release perforin to form a pore in the target cell's membrane, through which granzyme B enters to trigger caspase (death molecule) that enters the nucleus and breaks up the cell DNA |
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Term
| True or False: NK cells die after doing their job. |
|
Definition
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|
Term
| Why is apoptosis preferable is areas such as the brain and lungs? |
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Definition
| -cells die without inflammation |
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Term
| Briefly describe the complement system. |
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Definition
| -complement creates pores in the cell membrane that results in cell lysis |
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Term
| Briefly outline the innate immune system |
|
Definition
-responds very fast, cytokines are released by macrophages within minutes of an infection
-recognizes PAMP molecules (basic structural components on pathogens) |
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Term
| Where do T-cells mature? B-cells? |
|
Definition
-T-cells= thymus
-B-bells= bone marrow |
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Term
| Humoral immunity occurs via __-cells while cell-mediated immunity occurs via __-cells. |
|
Definition
-B-cells using antibodies
-T-cells using cytotoxic lymphocytes to kill virus infected cells and secretion of cytokines |
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Term
| In contrast to innate immunity, adaptive immunity is (faster/slower) to respond, recognizes (individual/varied) pathogens, and (has/lacks) long-term memory. |
|
Definition
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|
Term
| Where is cowpox evident on an infected cow? |
|
Definition
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|
Term
| Does cowpox only affect cows? |
|
Definition
| -NO, also affects humans and other animals, either directly or via rats |
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Term
| Which region of an antibody (Ab) changes? |
|
Definition
|
|
Term
| PRACTICE DRAWING AN ANTIBODY (slide 12 of L2) |
|
Definition
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|
Term
| What is the significance of the relative size of a IgG versus a bacterium? |
|
Definition
| -IgG is so small that it can cover the entire bacterium en masse |
|
|
Term
|
Definition
-B-cell receptors that eventually detach from the B-cell to become antibodies
-each has its own set of unique set of BCRs |
|
|
Term
| What do B-cells do upon activation? |
|
Definition
| -they clonally expand to make replica B0cells with same unique set of BCRs |
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|
Term
| When do B-cells become plasma cells? |
|
Definition
| -when their BCRs are released as antibodies |
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|
Term
|
Definition
-a stretch of 5-7 AAs on a protein that is recognized by BCRs
-generally situated on the outside of the antigen or pathogen |
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Term
| Antibodies recognize the (outside/inside) of a pathogen with cell-mediated response senses the (outside/inside) portion. |
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Definition
|
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Term
| What are the functions of Ab opsonization? |
|
Definition
-Ab bind to pathogens via their Fab region
-the exposed Fc region is recognized by Fc receptors on the surface of macrophages, neutrophils, and NK cells
-macrophages and neutrophils phagocytize the opsonized pathogen (extracellular pathogens)
-NK cells do not phagocytize pathogens, they kill then (intracellular pathogens) |
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Term
| Describe how Ab neutralize toxins and viruses. |
|
Definition
-Ab attach to pathogens and toxins
-this prevents them from recognizing and attaching to their receptors on cells |
|
|
Term
| What is the fat of B-cell clones? |
|
Definition
| -some become plasma cells while others stop proliferating and become memory B-cells |
|
|
Term
| What is the function of plasma cells? |
|
Definition
| -secrete Ab molecules that have the same Fab structure as that of the BCR |
|
|
Term
| What is the function of memory cells? |
|
Definition
-circulate as B-cells with BCR on their surface that survive until the individual dies
-they can be reactivated if the animal is re-infected or re-vaccinated with the same pathogen |
|
|
Term
| How can we achieve diversity of BCR and Ab? |
|
Definition
| -they make a random choice of gene segments by recombination |
|
|
Term
| Compare/Contrast B-cells and T-cells |
|
Definition
-B-cells: mature in bone marrow, have B-cell receptors (BCRs) on surface, recognize unprocessed Ags
-T-cells" mature in thymus, have T-cell receptors (TCRs) on surface, recognize only processed peptide molecules |
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Term
| TCRs (what does this stand for?) only recognize (processed/unprocessed) peptide molecules presented by __________ molecules. |
|
Definition
-TCR= T-cell receptors
-processed
-major histocompatibility (MHC) |
|
|
Term
| Once a dendritic cell has captured an Ag, what happens to it? |
|
Definition
| -takes it to the nearest lymph node, then attaches to an MHC molecule to be eaten by B-cells and T-cells |
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|
Term
| True or False: Viral antigens are usually 9-14 AAs long, thus TCRs do not need an MHC to present the antigen to them. |
|
Definition
| FALSE, they do need it presented by an MHC |
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Term
| Why can we not simply inject somebody with the epitopes that are recognized by the antibodies? |
|
Definition
| -the epitopes are dependent on antigen conformation. if we destroy the conformation, then they will no longer be the epitope, just AA fragments. |
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Term
| What is different b/n the epitopes that are recognized by B-cells and T-cells? |
|
Definition
-B-cells recognize surface epitopes (unprocessed)
-T-cells recognize epitopes on the inside of Ags, thus they muct be broken down and the epitopes presented by MHC molecules |
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|
Term
| True or False: T-cells can only recognize an epitope when it is presented by an MHC molecule, thus forming a complex. |
|
Definition
|
|
Term
| What occurs in an autoimmune disease? |
|
Definition
| -T-cells start to recognize our own proteins and begin the process of apoptosis |
|
|
Term
| What are the 3 types of T-cells? |
|
Definition
-cytotoxic T-lymphocytes (CTL)
-helper T-cells (Th)
-regulatory T-cess (T-reg) |
|
|
Term
|
Definition
-cytotoxic T-lymphocytes
-kill cells if its TCRs recognize the peptide presented by an MHC I but DOES NOT KILL EXTRACELLULAR BACTERIA |
|
|
Term
|
Definition
-helper T-cells
-their TCR can only recognize a peptide presented by an MHCII molecule on antigen presenting cells (APC), then they will secrete cytokines that help B-cells produce Ab
-Th turn on immune response |
|
|
Term
|
Definition
-regulatory T-cells
-they have TCR that recognize a peptide presented by MHC II but they swith OFF the immune response |
|
|
Term
| Why is it significant that Th cells use MHC II and cytotoxic T-cells use MHC I? |
|
Definition
| -MHC I is everywhere, while MHC II is rare, thus it is significantly more specific |
|
|
Term
|
Definition
| -comes from within the cell |
|
|
Term
|
Definition
| -comes from outside the cell (thus they have been phagocytized) |
|
|
Term
| MHC I molecules display small (endogenous/exogenous) peptides that are 8-10 AAs long. |
|
Definition
|
|
Term
| How do cytotoxic T-cells (CTLs) kill? |
|
Definition
-they first release perforin that drills a hole in the cell
-then it injects granzyme through the hole into the cell, this causes the cell to undergo apoptosis |
|
|
Term
| What occurs in type I diabetes? |
|
Definition
| -an autoimmune disease where cytotoxic T-cells recognize insulin peptides on MHC molecules, thus it kills insulin-producing beta cells in the pancreas |
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|
Term
| MHC II molecules are present only on the surface of cells called ___________. Examples? |
|
Definition
-antigen presenting cells )APC)
-ex: macrophages, dendritic cells, and B-cells |
|
|
Term
| MHC II molecules displar only (endogenous/exogenous_ peptides derived from phagocytosis. These peptides are recognized by what? |
|
Definition
-exogenous
-T-helper and T-reg cells |
|
|
Term
| All the lymph in the body drains to the ________. |
|
Definition
|
|
Term
| True or False: Anything that enters the GI and respiratory tracts encounters the MALT. |
|
Definition
|
|
Term
| Where in the lymph node are T-cells and B-cells located? |
|
Definition
|
|
Term
| What is the general purpose of germinal centers? |
|
Definition
| -to form antibodies and B-cell replication |
|
|
Term
Definition: Tolerance
-what is the pass rate? |
|
Definition
-the process by which all of our T-cells and B-cells are presented our own proteins while they are developing, testing to see if they will kill our own cells
-only 3% pass the test |
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|
Term
| Pathogens will first activate the innate immune system via _____ molecules binding to PRR (inflammation). |
|
Definition
|
|
Term
| True or False: The innate immune system must be activated inorder for the adaptive immune response to become activated. |
|
Definition
|
|
Term
Between innate and adaptive immunities, which is:
a) more specific?
b) quicker?
c) has memory? |
|
Definition
a) adaptive
b) innate (adaptive= 4-7d)
c) ONLY adaptive has memory |
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