Definitions (1)

Question 1

pattern recognition receptors (PRR)

Answer 1

receptors on cells of the innate immune system capable of recognizing broad molecular patterns on molecules expressed by pathogens

expressed by macrophages, dendritic cells, neutrophils, & epithelial cells

Question 2

pathogen associated molecular patterns (PAMPs)

Answer 2

broad molecular patterns on molecules expressed by pathogens and recognized by PRRs

absent or shielded in host cells

Question 3

complement system

Answer 3

made up of a series of pro-proteins made by the liver

activation of these proteins can occur via PAMPs, antibody-antigen complexes, or mannose binding lectin

this leads to a cascade of cleavages of the pro-proteins into the active form

net result: formation of the membrane attack complex (MAC) that forms pores in the target cell membrane leading to death

Question 4

PRRs:
mannose binding lectin
&
surfactant proteins

Answer 4

recognizes mannose on pathogens

oligomeric structure to bind w/ high affinity to mannose & fucose residues w/ correct spacing

crucial for PAMP recognition

SPs: similar to MBLs

both: secreted from cells
both: involved in phagocytosis & complement release

Question 5

PRRs:

macrophage mannose receptor (MMR)

Answer 5

similar to mannose binding lectin (MBL)

cell surface receptor (not secreted from cells)

phagocytic receptor

Question 6

PRRs:

scavenger receptors

Answer 6

recognize anionic polymers & acetylated LDL

shielded in host cells

cell surface receptor

phagocytic receptor

Question 7

PRRs:

fMLP receptors

Answer 7

recognize fMet-Leu-Phe (start of many bacterial polypeptides)

cell surface receptor

not a phagocytic receptor

binding of PAMPs leads to production of cytokines

Question 8

PRRs:

Toll-Like receptors (TLRs)

Answer 8

present on the cell surface or in endosomes

recognize viral & bacterial PAMPs

transduce intracellular signals & release cytokines in response to PAMP binding

Question 9

PRRs:

NOD proteins

Answer 9

contain a nucleotide binding oligomerization domain

recognize following PAMPs:

• NOD1: most bacteria
• NOD2: gram-negative bacteria

located in the cytosol of epithelial cells

activate caspases

Question 10

inflammation roles:

neutrophils (3)

Answer 10

phagocytosis

reactive oxygen & nitrogen species

antimicrobial

Question 11

inflammation roles:

macrophages (6)

Answer 11

phagocytosis

inflammatory mediators

antigen presentation

reactive oxygen & nitrogen species

cytokines

complement proteins

Question 12

inflammation roles:
dendritic cells (5)

Answer 12

antigen presentation

costimulatory signals

reactive oxygen species

interferon

cytokines

Question 13

inflammation roles:

natural killer cells (3)

Answer 13

lysis of viral-infected cells

interferon

macrophage activation

Question 14

(adhesion molecule)-(innate immune cell receptor) interactions mediate rolling

chemokines/chemoattractants induce change in (innate immune cell receptor)

(innate immune cell receptors) adhere firmly to (adhesion molecules)

Answer 14

selectin-mucin interactions mediate rolling

chemokines/chemoattractants induce change in integrins

integrins adhere firmly to ICAMs

Question 15

cross-presentation

Answer 15

antigen-presenting cells take up, process, & present extracellular antigens w/ MHC class I molecules to CD8 T cells (cytotoxic T cells)

Question 16

co-stimulation

Answer 16

accessory signals provided by the antigen presenting cells required for priming T cells

usually a combination of surface molecules & cytokines

aka signal 2

Question 17

MHC restriction

Answer 17

T lymphocytes recognize peptide antigens bound to an individual’s own MHC proteins on antigen presenting cells (APCs)

Question 18

Langerhans cells

Answer 18

immature dendritic cells in the skin

specialized for antigen capture

Question 19

genes that encode class I MHC molecules

genes that encode class II MHC molecules

Answer 19

HLA-A, B, & C

HLA-DR, DQ, & DP

Question 20

class I MHC protein structure

class II MHC protein structure

Answer 20

heavy chain (alpha 1, 2, & 3) + beta-2-microglobulin

alpha (1 & 2) & beta (1 & 2) chains

Question 21

class I MHC-expressing cell types

class II MHC-expressing cell types

Answer 21

all nucleated cells

professional APCs, macrophages, & B cells

Question 22

peptide binding motif

Answer 22

interaction of peptides w/ MHC molecules is constrained by the peptide binding cleft

pockets in the floor of the cleft accommodate residues of the peptide & anchor it

dif MHC proteins have dif shaped binding clefts & bind peptide w/ dif anchor residues

peptides w/ dif primary structures can bind to the same type of MHC protein as long as they contain the proper anchor residues

Question 23

enzyme responsible for generating class I peptides

enzyme responsible for generating class II peptides

Answer 23

proteasome

cathepsins

Question 24

site of class I peptide loading & accessory molecule

site of class II peptide loading & accessory molecule

Answer 24

ER
TAP

MIIC vesicle
invariant chain, DM

Question 25

T cell priming

Answer 25

naive T cells must first be activated by MHC-restricted interaction w/ professional APC (usually a DC) before the effector functions of macrophages, B cells, & CD8+ cytolytic T cells are gained

Question 26

direct vs indirect MHC recognition

Answer 26

direct: TCR of recipient T cell recognizes foreign MHC (regardless of the peptide presented) & destroys the target cell
indirect: foreign MHC (as a protein) is acquired by the host APC, processed, & presented on recipient MHC to recipient T cells

Question 27

HLA typing & 2 methods

Answer 27

determining the MHC type (haplotype) of the recipient & donor prior to transplantation

methods: lymphocytotoxicity assay & molecular typing

Question 28

dendritic cells:

morphology

tissue distribution

origins

Answer 28

large, long dendrite-like extensions that mediate antigen uptake & cell-cell contact

all tissues except immune-privileged CNS, eye, & testes

bone marrow hematopoietic CD34+ progenitors or myeloid (CMP) or lymphoid (CLP) progenitors

Question 29

functions of dendritic cells (6)

Answer 29

detect danger signals
capture antigen
migrate
stimulate naive T & B cells
secrete cytokines
bridge innate & adaptive immune responses

Question 30

preventative vs. therapeutic vaccines

Answer 30

preventative: used against infections, stimulate a primary immune response to infectious agents, leads to memory response developments; antigens are given w/ adjuvants to target, activate, & bias specific DC responses
therapeutic: harder to develop, required to modulate or reprogram an established memory response, treat chronic infections & cancer