Lecture 4

Question 1

Four Types of Antigens

Answer 1

Immunogens
Haptens
Tolerogens
Mitogens

Question 2

Immunogen

Answer 2

Immune Response Generator

• target of response is immunogen
• inc. responsiveness w/ exposure
• PROTEINS mainly

Question 3

Haptogens

Answer 3

Small molecules that can cause immune response IF linked to a carrier (cannot by self)
-Hapten ALONE maybe recognized after 1st exposure

Question 4

Drugs are like haptogens bc?

Answer 4

They are too small to cause allergic reaction (NORMALLY)

Question 5

Tolerogens

Answer 5

Immune Response Generator

• target of response is tolerogen
• Subsequent exposures have DEC. responsivness

Question 6

Mitogen & Examples

Answer 6

Polyclonal Activators

• induce non-spec. mitosis & diff.
• T & B cells
• EX: LPS act. B cells & induce macrophage CK prod.
• EX: Superantigen (sAg) stabilize TCR:MHC interaction, causes CK storm = fever, rash, organ failure, shock

Question 7

Epitope

Answer 7

Smallest unit of Ag recog. by receptors

Question 8

Multivalent

Polyvalent

Answer 8

• multiple copies of same epitope

- diff. epitopes (mitogens)

Question 9

Confirmational Epitope

Linear Epitope

Answer 9

• in native structure, recog. by AB, b cells, innate

- in denatured structure, recog. by T cells, AB, b cells, innate

Question 10

Immunogenicity Small to Large based on valence

Answer 10

univalent, small AG, multivalent, polyvalent

Question 11

Adjuvant

Answer 11

Enhances activity of substances its mixed with

-increases immunogenicity

Question 12

Alum

Answer 12

Adjuvant

• insoluble Al salts that prolong antigen persistence
• used in VACCINES

Question 13

MF59

Answer 13

Adjuvant

• oil in water emulsion containing detergent
• prolongs antigen persistence, solubilizes vaccine components

Question 14

Pathogens generally have….

Answer 14

> 1 antigen, each with >1 epitope

Question 15

Genetics alter immune response in individual…how? (3)

Answer 15

• genes encoding MHC
• genes encoding BCR/TCR segments
• genes encoding CK/CKR

Question 16

PRR Catagories

Answer 16

Signaling - membrane bound or cytoplasmic
Endocytic - bound to phagocyte membrane
Secreted - bind to pathogen surface, act. complement, act as opsonins to promote phagocytosis

Question 17

Types of Signaling PRRs

Answer 17

TLRs - toll like receptors
NLRs - NOD like recepetors (nucleotide binding oligomerization domain)
RLHs or RLRs - Rig-I-Like helicases - retinoic acid inducable gene 1

Question 18

TLR Characteristics

Answer 18

• Membrane bound (cell surface OR endosomes)
• homodimer
• on cells of immune system

Question 19

NLR Characteristics

Answer 19

• Cytoplasmic
• NOD & NLRP subfamilies
• in many cell types, including epithelial

Question 20

RLH / RLR Characteristics

Answer 20

• Cytoplasmic

- in many cell types

Question 21

TLR detect antigens where and what?

Answer 21

Outside - bacteria, fungi

Endosomes - viral

Question 22

TLR activation steps of cell surface TLR

Answer 22

• binding of PAMP = dimerization
• interaction w/ adapter proteins
• Kinase cascade
• inactivation of IkB, activation of NFkB
• transcript. of pro-inflam CK genes (IL1, IL6, TNF-a)

INFLAMMATION RESPONSE (effective against bacteria)

Question 23

TLR activation steps of endosomal TLR

Answer 23

• binding
• dimerization
• interaction w/ adapter proteins
• act. interferon regulatory factor (IRF)
• transcrip. of anti-viral CK genes (IFN-a, IFN-B)-type 1 IFN

ANTI-VIRAL Response

Question 24

NLRs detect…

• NOD
• NLRP

Answer 24

cytoplasmic antigens

• NOD = peptidoglycan (bacterial) components
• NLRP = inflammasome form due to pathogen, cell damage, stress

Question 25

NOD Activation

Answer 25

Same as surface TLR | -INFLAMMATORY RESPONSE (antibacterial)

Question 26

NLRP Activation

Answer 26

Monomer inactive in healthy - stress = dissociation of accessory proteins - dimerization = inflammasome form - CK processing for secretion

Question 27

RLHs Detect

Answer 27

Cytoplasmic viral RNA - RIG-I:ssRNA - MDA-5: dsRNA

Question 28

RLHs Activation

Answer 28

- Recog. of virus in cytoplasm - Dimerization & assoc. w/ proteins attached to mito membrane - Act. of signalingn pathways for type 1 IFN & pro-inflamm. CK production (same as other PRR sig. pathways)

Question 29

Secreted PRRs Mech

Answer 29

- secreted - bind to pathogen surface = phagocytosis or complement activation - Collectins bind carbs - C reactive protein (CRP) binds to phosphocholine