Exam 4: Immune System

Question 1

MHC Class I vs MHC Class II

Answer 1

A) MHC Class I:
Virus infected cells
Shows intracellular antigens
Cytotoxic T cells express CD8 to bind here

B) MHC Class II:
APCs that have ingested bacteria
Shows extracellular antigens
Helper T cells express CD4 to bind here

Question 2

Innate vs Adaptive Immunity

Answer 2

Innate → 1st defense, non specific

Adaptive → specific response [on past exam]

Question 3

Which chemical mediator stimulates/ limits inflammation?

Answer 3

Eicosanoids (specifically prostaglandins)

Question 4

Which chemical mediator recruits immune cells to the area?

Answer 4

cytokines (specifically chemokines)

Question 5

Hypersensitivity reactions: Type 1 vs Type 2 vs Type 3 vs. Type 4

Answer 5

Type I :
● Immediate 
● Mediated by IgE 
● Treat with Epi 
● Examples: Asthma, hay fever, urticaria (hives), anaphylaxis 

Type II 
● Hours to days 
● Mediated by IgG or IgM 
● Formation of antibody antigen complex 
● Examples: mismatched Rh factor

Type III
● Hours to days
● Mediated by IgG or IgM
● Antibody antigen complexes form in circulation and are deposited in basement membranes
● Examples: glomerulonephritis, skin rash, arthritis, lupus

Type IV
● 2 - 3 days after exposure
● Cell Mediated Reaction
● Involves macrophages, cytotoxic and helper T cells
● Examples: contact dermatitis (poison ivy), T1DM, Mantoux TB test

Question 6

Fetal development (ductus arteriosus):
Which drug:
a) maintains shunt
b) closes shunt

Answer 6

Alprostadil maintain shunt

Indomethacin (NSAID) closes shunt

Question 7

Azathioprine
Drug class:
MOA:

Answer 7

Drug class: Prodrug

MOA: False nucleotide = Inhibits DNA and RNA synthesis

Question 8

Mycophenolate Mofetil

Drug class:
MOA:

Answer 8

Drug class: Prodrug

MOA: Inhibits IMP dehydrogenase (rate limiting step in purine synthesis) → decreased lymphocyte proliferation → Inhibiting DNA and RNA synthesis

Question 9

Cyclosporine

Drug Class:
MOA:

Answer 9

Drug Class: Calcineurin Inhibitor

MOA: Binds cyclophilin → inhibits calcineurin→ prevent activation of IL2 → blocks T cell

Question 10

Tacrolimus, Sirolimus

Drug Class:
MOA:

Answer 10

Drug Class: Calcineurin Inhibitor

MOA: Binds FKBP → inhibits calcineurin= prevent activation of IL2 → blocks T cell

Question 11

Hydroxychloroquine

Answer 11

Drug class: Calcineurin Inhibitor

MOA:
Inhibits processing of peptide antigens and assembly into MHC complexes

Question 12

Adalimumab
Drug Class:
MOA:
Contraindications:

Answer 12

Drug Class: Monoclonal Antibodies

MOA: Anti TNF 𝛂 antibody

Contraindications: bone marrow suppression, breast feeding, infections, TB, live virus vaccination

Question 13

Abatacept

Drug class:
MOA:

Answer 13

Drug class:
Monoclonal Antibodies

MOA: Chimeric mouse-human IgG that competitively blocks IL-2 receptor
→ blocks T cell activation

Question 14

Alefacept

Drug Class:
MOA:

Answer 14

Drug Class: Monoclonal Antibodies

MOA: Mimics CTLa-4 → inhibits CD80/86 → blocks T cell activation

Question 15

Basiliximab

Drug class:
MOA:
Contraindications:

Answer 15

Drug class: Monoclonal Antibodies

MOA: Blocks CD2/LFA-3 costimulatory signal → blocks T cell activation

Contraindications: fungal infections, herpes, vaccination, viral infection, lymphoma, mannitol hypersensitivity, murine (mouse)protein hypersensitivity