Immunology Chapter 5

Front 1

What are the two major intracellular compartments, separated by membranes?

Back 1

cytosol, vesicular system

Front 2

Pathogens and their products can be found in either the...

Back 2

cytosolic or the vesicular compartment of the cells

Front 3

The MHC class I and class II molecules deliver peptides to the cell from...

Back 3

two intracellular compartments: the cytosol and the vesicular system

Front 4

Peptides that bind to MHC class I molecules are...

Back 4

actively transported from the cytosol to the ER

Front 5

Peptides for transport into the endoplasmic reticulum are generated...

Back 5

in the cytosol

Front 6

Retrograde transport from the ER to the cytosol enables exogenous proteins...

Back 6

to be processed for cross-presentation by MHC class I molecules

Front 7

Newly synthesized MHC class I molecules are retained...

Back 7

in the ER until they bind a peptide

Front 8

Many viruses produce immunoevasins that...

Back 8

interfere with antigen presentation by MHC class I molecules

Front 9

Peptides presented by MHC class II molecules are generated...

Back 9

in acidified endocytic vesicles

Front 10

The invariant chain directs newly synthesized MHC class II molecules...

Back 10

to acidified intracellular vesicles

Front 11

A specialized MHC class II-like molecule catalyzes...

Back 11

loading of MHC class II molecules with peptides

Front 12

Stable binding of peptides by MHC molecules provides...

Back 12

effective Ag presentation at the cell surface

Front 13

Many proteins involved in Ag processing and presentation are encoded by...

Back 13

genes within the major histocompatibility complex

Front 14

The protein products of MHC class I and class II genes...

Back 14

are highly polymorphic

Front 15

MHC polymorphism affects Ag recognition by T cells by influencing both...

Back 15

peptide binding and the contacts between T-cell receptor and MHC molecule

Front 16

Alloreactive T cells recognizing nonself MHC molecules are...

Back 16

very abundant

Front 17

Many T cells respond to...

Back 17

superantigens

Front 18

MHC polymorphism extends the range of...

Back 18

Ags to which the immune system can respond

Front 19

A variety of genes with specialized functions in immunity...

Back 19

are also encoded in the MHC

Front 20

Specialized MHC class I molecules act as ligands for...

Back 20

the activation and inhibition of NK cells

Front 21

The CD1 family of MHC class I-like molecules is encoded outside the MHC and...

Back 21

presents microbial lipids to CD1-restricted T cells

Front 22

5-1 The MHC class I and class II molecules deliver peptides to the cell surface...

Back 22

The MHC class I and class II molecules deliver peptides to the cell surface FROM TWO INTRACELLULAR COMPARTMENTS

Front 23

5-2 Peptides that bind to MHC class I molecules are actively transported...

Back 23

Peptides that bind to MHC class I molecules are actively transported FROM THE CYTOSOL TO THE ER

Front 24

5-3 Peptides for transport into the ER are...

Back 24

Peptides for transport into the ER are GENERATED IN THE CYTOSOL

Front 25

5-4 Retrograde transport from the ER to the cytosol enables...

Back 25

Retrograde transport from the ER to the cytosol enables EXOGENOUS PROTEINS TO BE PROCESSED FOR CROSS-PRESENTATION BY MHC CLASS I MOLECULES

Front 26

5-5 Newly synthesized MHC class I molecules are retained in...

Back 26

Newly synthesized MHC class I molecules are retained in THE ER UNTIL THEY BIND A PEPTIDE

Front 27

5-6 Many viruses produce immunoevasins that...

Back 27

Many viruses produce immunoevasins that INTERFERE WITH ANTIGEN PRESENTATION BY MHC CLASS I MOLECULES

Front 28

5-7 Peptides presented by MHC class II molecules are generated...

Back 28

Peptides presented by MHC class II molecules are generated IN ACIDIFIED ENDOCYTIC VESICLES

Front 29

5-8 The invariant chain directs newly synthesized MHC class II molecules...

Back 29

The invariant chain directs newly synthesized MHC class II molecules TO ACIDIFIED INTRACELLULAR VESICLES

Front 30

5-9 A specialized MHC class II-like molecule catalyzes...

Back 30

A specialized MHC class II-like molecule catalyzes LOADING OF MHC CLASS II MOLECULES WITH PEPTIDES

Front 31

5-10 Stable binding of peptides by MHC molecules provides...

Back 31

Stable binding of peptides by MHC molecules provides EFFECTIVE ANTIGEN PRESENTATION AT THE CELL SURFACE

Front 32

5-11 Many proteins involved in antigen processing and presentation are encoded by...

Back 32

Many proteins involved in antigen processing and presentation are encoded by GENES WITHIN THE MAJOR HISTOCOMPATIBILITY COMPLEX

Front 33

5-12 The protein products of MHC class I and class II genes...

Back 33

The protein products of MHC class I and class II genes ARE HIGHLY POLYMORPHIC

Front 34

5-13 MHC polymorphism affects antigen recognition by T cells by influencing both...

Back 34

MHC polymorphism affects antigen recognition by T cells by influencing both PEPTIDE BINDING AND THE CONTACTS BETWEEN T-CELL RECEPTOR AND MHC MOLECULE

Front 35

5-14 Alloreactive T cells recognizing MHC molecules...

Back 35

Alloreactive T cells recognizing MHC molecules ARE VERY ABUNDANT

Front 36

5-15 Many T cells respond to...

Back 36

Many T cells respond to SUPERANTIGENS

Front 37

5-16 MHC polymorphism extends...

Back 37

MHC polymorphism extends THE RANGE OF ANTIGENS TO WHICH THE IMMUNE SYSTEM CAN RESPOND

Front 38

5-17 A variety of genes with specialized functions in immunity...

Back 38

A variety of genes with specialized functions in immunity ARE ALSO ENCODED IN THE MHC

Front 39

5-18 Specialized MHC class I molecules act as...

Back 39

Specialized MHC class I molecules act as LIGANDS FOR THE ACTIVATION AND INHIBITION OF NK CELLS

Front 40

5-19 The CD1 family of MHC class I-like molecules is encoded...

Back 40

The CD1 family of MHC class I-like molecules is encoded OUTSIDE THE MHC AND PRESENTS MICROBIAL LIPIDS TO CD1-RESTRICTED T CELLS

Front 41

There is strong selective pressure in favor of any pathogen that has mutated in such a way that it escapes presentation by an MHC molecule. What two properties of the MHC make it difficult for pathogens to evade immune responses in this way?

Back 41

1. The MHC is polygenic: it contains several different MHC class I and MHC class II genes, so that every individual possesses a set of MHC molecules with different ranges of peptide-binding specificities.
2. The MHC is highly polymorphic: there are multiple variants of each gene within the population as a whole.

Front 42

What are the two major intracellular compartments, separated by membranes?

Back 42

the cytosol and the vesicular system

Front 43

TAP1 and TAP2 form what?

Back 43

TAP1 and TAP2 form a peptide transporter in the ER membrane

Front 44

The PA28 proteosome activator binds to what?

Back 44

The PA28 proteosome activator binds to either end of the proteosome

Front 45

What is TAP an acronym for?

Back 45

Transporters associated with Antigen Processing

Front 46

The two TAP proteins form a heterodimer, and mutations in either TAP gene can...

Back 46

The two TAP proteins form a heterodimer, and mutations in either TAP gene can PREVENT ANTIGEN PRESENTATION BY MHC CLASS I MOLECULES

Front 47

MHC class I molecules do not leave the ER unless...

Back 47

MHC class I molecules do not leave the ER unless THEY BIND PEPTIDES

Front 48

MHC class I molecules do not leave the ER unless they bind peptides. Briefly explain the process (Fig. 5.5)

Back 48

1. Partly folded MHC class I alpha chains bind to calnexin until beta 2-microglobulin binds.
2. MHC class I alpha:beta 2 m complex is released from calnexin, binds a complex of chaperone proteins (calreticulin, Erp57) and binds to TAP via tapasin.
3. Cytosolic proteins and defective ribosomal products (DRiPs) are degraded to peptide fragments by the proteosome. TAP delivers peptides to the ER.
4. A peptide binds the MHC class I molecule and completes its folding. The MHC class I molecule is released from the TAP complex and exported to the cell membrane.