Antigen Presentation

Question 1

Definitions -

1. Antigen
2. Cognate Antigen
3. Epitope
4. Paratope

Answer 1

1. something that causes the immune system to create antibodies specifically targeting that something
2. antigen that a given B cell’s receptors recognize
3. (antigenic determinant), part of the antigen that the antibody recognizes and attaches
4. part of the antibody that recognizes and attaches to the epitope

Question 2

Two Methods -

1. What are the two methods?
2. cells constantly break down ___ created ____ and present them on the cell surface
3. What is MHC I?
4. ___ can do this
5. allow us to ?

Answer 2

1. MHC I = proteins created within the cell OR MHC II = eat protein outside of the cell
2. proteins, within the cell
3. Major Histocompatibility Complex 1
4. almost all cells of the body
5. see what is being made in the cells

Question 3

Two Methods -

1. special cells ___, break it down, and present the fragments on the cell surface
2. What is MHC II?
3. ___ can do this
4. allows us to see ___

Answer 3

1. eat protein (phagocytosis)
2. Major Histocompatibility Complex II
3. only antigen presenting cells
4. what is happening outside the cell

Question 4

Antigen Presentation by MHC I -

1. ___ are constantly broken down into fragments
2. the fragments are presented on the surface of the cell by ___
3. ___ constantly inspect the presented fragments
4. ___ inspect which sends the “___” signal if cell is normal
5. NK cells posses receptors for self molecules that prevent ___

Answer 4

1. endogenous proteins (proteins made in cells)
2. MHCs
3. Cytotoxic Lymphocytes (Killer T Cells)
4. NK cells, don’t kill
5. their activation by uninfected cells

Question 5

MHCs -

1. molecules that bind to ___ created in the cell and bring them to the surface of the cell
2. they present the antigen to (2)

Answer 5

1. protein fragments

2. T cells and NK cells

Question 6

MHC I -

1. constantly updating ___

Answer 6

1. billboard that advertises what is being made in the cell

Question 7

MHC I -

1. presents what 3 types of proteins
2. ___ expresses MHC I molecules

Answer 7

1. ordinary cellular (enzymes and structural proteins), proteins encoded by viruses, and parasite proteins
2. almost every cell in the body

Question 8

MHC I Antigen Presentation -

1. ___ constantly chew up cellular protein, normal function is ___
2. most protein fragments (___) are further broken down into ___ for ___
3. some peptides are brought to the ___ where they are attached to ___ molecules (list two)
4. peptides are bound to ____ molecules
5. the ___ is transported to the ___

Answer 8

1. proteasomes, dealing with defective proteins
2. peptides, singular AA for reuse
3. ER, MHC I
4. MHC I
5. peptide-MHC I complex, cell surface

Question 9

Proteasomes -

1. most of the peptides are broken down into individual ___ for reuse
2. Some of the peptides are carried to the ___

Answer 9

1. AA

2, ER

Question 10

MHC I specifics -

1. # MHC I genes (3 from mom, 3 from dad)
2. What is HLA?
3. located on ___
4. each MHC I protein pairs with ____
5. List the three gene variants
6. This variability allows MHC I molecules an ability to ?

Answer 10

1. 6
2. human leukocyte antigen
3. chromosome six
4. another protein
5. HLA-A (480), HLA-B (800), HLA-C (260)
6. bind many different kinds of peptides

Question 11

MHC I specifics -

1. MHC I molecules have a ___ in which a peptide must fit
2. most peptides bout to MHC I molecules are # AA long
3. the peptide is anchored at ___
4. longer peptides are allowed to ?

Answer 11

1. groove (closed at both ends)
2. 8-11
3. both ends
4. bulge in the center

Question 12

Killer T Cells Inspect MHC I Peptides -

1. Killer T cells (____) inspect the peptides displayed by MHC I molecules
2. ___ also inspect MHC I (don’t use ____)

Answer 12

1. cytotoxic lymphocytes

2. NK cells, kill signal

Question 13

Antigen Presentation by MHC II -

1. Antigen presenting Cells (APCs) do what?
2. the proteins are contained within a ___
3. MHC II molecules are made in the ___ and injected into the __
4. a special protein called ____ protects the binding area of the MHC II
5. The invariant chain - MHC II complex is release into an ___
6. The phagosome (w/ extracellular protein) is fused with the ___

Answer 13

1. eat extracellular proteins
2. phagosome
3. cytosol, ER
4. invariant chain protein
5. ensosome
6. endosome (with the MHC II)

Question 14

Antigen Presentation by MHC II -

1. the extracellular protein is broken down by ___
2. produces ___
3. the invariant chain protein is broken down by ____
4. the MHC II complex is ___
5. the extracellular protein fragments (peptides) do what?
6. The MHC II peptide is transported to ____

Answer 14

1. enzymes within the endosome
2. protein fragments (peptides)
3. enzymes within the endosome
4. preserved
5. load on MHC IIs
6. cell surface and displayed

Question 15

Antigen Presenting Cells -

1. List the four types of antigen presenting cells
2. are all ___ cells
3. are all made in ___
4. must migrate where
5. must be ____ before they can function
6. are all ___

Answer 15

1. activated dendritic cells, activated macrophages, activated B cells, and activated neutrophils
2. white
3. bone marrow
4. out to various sites in the body
5. activated
6. phagocytic

Question 16

Invariant Chain -

1. when the MHC II is in the ER, we don’t want what?
2. The invariant chain sits in the groove and stops ___
3. What is the invariant chains job?

Answer 16

1. other proteins filling the groove
2. other proteins from binding
3. guide the MHC II through the ER and Golgi apparatus to an endosome

Question 17

Endosome and phagosome fuse -

1. The invariant chain is ___
2. the ___ is broken down
3. The MHC II is ___
4. the ___ fits in the open groove of the MHC II complex and is transported to the ___

Answer 17

1. broken down
2. exogenous protein
3. preserved
4. protein fragment, APC’s surface

Question 18

MHC II Specifics -

1. MHC II molecules are ___ at both ends
2. Most peptides bound to MHC II molecules are # AA long
3. the peptide is ___
4. ends of the peptides are ___

Answer 18

1. open
2. 13-25
3. anchored
4. allowed to hang over

Question 19

Antigen Presenting Cells -

1. they are really “____ cells”
2. APCs present the antigen to (2)
3. Provide (2) required for T cell activation

Answer 19

1. T cell activating cells
2. killer t cells and helper t cells
3. high levels of MHCs and co-stimulatory molecules

Question 20

What are the four types of APCs?

Answer 20

1. activated dendritic cells
2. activated macrophage
3. activated B cell
4. activated neutrophils

Question 21

Activated dendritic Cells -

1. ___ the immune response by activating ___ cells
2. ___ cells are located beneath ___
3. ___ are B or T cells which have never been activated
4. ____ are B or T cells which have been activated

Answer 21

1. initiate, virgin T
2. sentinel, epithelial cells
3. naïve or virgin lymphocytes
4. experienced lymphocytes

Question 22

DC (resting state) -

1. in normal tissue dendritic cells can take in __times their volume of ___ per hour
2. tike it in and ?
3. expressing some ___
4. Is it a good APC?

Answer 22

1. four, extracellular fluid
2. spit it back out (constantly tasting)
3. B7 (co-stimulator)
4. Not very good, especially to virgin T cells that require extensive receptor crosslinking and co-stimulation

Question 23

DC (activation) -

1. ___ signals from cells engaged in battle
2. ___ from (2)
3. ___ cells also give off chemical signals
4. recognition of “___”
5. recognize what
6. each receptor can identify ___
7. recognized patterns are very important ___ features of the pathogen, w/o these structures the pathogen would ___
8. Remember the (2) are specific to the invader

Answer 23

1. chemical
2. TNF, macrophages or neutrophils
3. dying
4. common molecular patterns
5. general characteristics of classes of invaders
6. many different pathogens
7. structural, not exist (not easy for the pathogen to disguise itself by mutating this segment)
8. BCRs and TCRs

Question 24

Toll Like Receptors (TLR) -

1. ___ (most are like TLRs)
2. example ___ recognizes ___ on bacterial cell walls
3. ___ detects the ___ of viruses
4. ___ recognizes the double stranded DNA of (2)
5. TLRs are on the cell’s ___ while others are ___
6. some coat the inside of ___

Answer 24

1. Patter recognition receptors
2. TLR4, LPS
3. TLR7, single stranded RNA
4. TLR9, bacteria and herpes simplex virus
5. surface, inside the cell
6. phagolysosomes

Question 25

Activated Dendritic Cells - 1. once activated, the ADC stays in the ___ for about how long? 2. how much does it eat? 3. leaves the area through the ___ to the nearest ___, takes about ____ to reach this, then lives there for ___ 4. ___ expression of MHC I molecules, if infected with a virus at the battle ground it will be displayed on ___ 5. ___ expression of B7 co-stimulatory proteins

Answer 25

1. tissue, 6 hrs 2. much more, MHC IIs become loaded with antigens from the battle ground 3. lymphatic system, lymph node, a day, a week 4. increased, MHC I 5. increased

Question 26

Replacement Dendritic Cells - 1. prior to leaving the battle ground, ADCs make ___ the attract ___ into the area 2. the monocytes become ___ 3. the new DCs can be activated and carry new pictures of the battle to the ___

Answer 26

1. cytokines, monocytes 2. dendritic cells 3. lymph nodes

Question 27

Activated Dendritic Cells - 1. ___ cells that sample antigens in tissues 2. bring the samples to the ___ 3. present the antigen to ___ 4. ADC are ___ lived 5. ADC assures ___ 6. activated dendritic cells don't do ___

Answer 27

1. sentinel 2. lymph nodes 3. virgin T cells 4. short 5. an up to date picture of the battle 6. the killing, they get others to do the killing

Question 28

Activated Macrophages - 1. Sentinel cells: located ____, don't ___ like ADCs 2. Function (3)

Answer 28

1. in areas of the body exposed to the outside world, travel | 2. garage collectors, antigen presenting cells (re-stimulate activated T cells), and ferocious killers

Question 29

Activated Macrophages - 1. Only express enough __ and ___ molecules to function as APCs after (2) 2. Function to re-stimulate ___ 3. the T cells were activated by ___ in the ___ 4. experienced T cells need ____ 5. activated dendritic cells activate ___ 6. activated macrophages re-stimulate experienced ___

Answer 29

1. MHC and co-stimulatory molecules, activation by battle cytokines (IFNy) and recognizing patterns (Toll like receptor recognition 2. T cells 3. dendritic cells, lymph nodes 4. continual re-stimulation 5. virgin T cells 6. T Cells

Question 30

Activated B Cells - 1. Virgin B cells make little __ and little ___, not used ___ 2. activated by ? 3. experienced activated B cell are able to ? 4. also able to ___ antigen for presentation, displaying both ?

Answer 30

1. MHC II, B7, as APC at the beginning of a battle 2. meeting their cognate antigen 3. present antigens for helper T cells 4. concentrate, BCRs with antigen and MHC II with antigen (cross linked)

Question 31

Activated B Cells - Experienced ABC 1. BCR have very ___ affinity for their antigen 2. collect ___ 3. T cells need a threshold number of ___ and ___ to be activated 4. up regulate more ___ 5. speed? 6. Activated B cells have 11-10,000 fold ability to activate __ over other ___

Answer 31

1. high 2. a lot of the antigen 3. cross-linked TCRs and MHC IIs 4. B7 5. very fast, 30 minutes for a b cell to capture the antigen and present it on the cell surface on an MHC II complex 6. T cells over other APCs

Question 32

MHC I - 1. present ___ to ___ 2. ___ also scan MHC I (___ signal) 3. expressed in ___ 4. display proteins made ___ the cell

Answer 32

1. peptides (protein), CTLs 2. NK cells, don't kill 3. almost every kind of cell 4. inside

Question 33

MHC II - 1. present peptides to ___ 2. expressed ___ 3. advertise what is happening ___ the cell 4. by requiring that ___ only recognize presented antigen, the decision to deploy the adaptive immune system is not made by a single cell

Answer 33

1. helper T cells 2. exclusively on the cells of the immune system (APCs) 3. outside 4. helper T cells

Question 34

Summary - 1. if the invader is outside the cell: antibodies mark them for ___, marked and destroyed by the ___, eaten by ___ 2. If the invader is inside the cell: MHC I presentation shows ___ what's going on inside infected cells, chopped up protein can no longer ___ 3. Responsible for ___ of transplanted organ, explain

Answer 34

1. destruction, complement system, professional phagocytes 2. CTLs, hide fragments with folding (B cells may not see their cognate antigen due to the protein folding) 3. rejection, tissue typing designed to match MHC proteins of donor and recipient