Immunology- FC

Question 1

In what organelles does antigen is loaded onto MHC1? what about MHC2?

Answer 1

• MHC1: Rough ER
• MHC2: endosome
• think like this: MHC1 presents endogenously expressed peptide. so it should be expressed in cytosol and move into rough ER
  MHC2 presents exogenous peptide, which needs to be digested in endosome first.

Question 2

After splenolactomy, how would CBC change?

Answer 2

pancytosis
: increased RBC, platelet, WBC

• spleen is site of storage of blood cells (via sequestration) and destruction. loss of spleen will cause increase in ALL TYPES of blood cells

Question 3

Which CD cell surface marker on macrophage mediates endotoxin (LPS) mediated shock?

Answer 3

CD14

Question 4

Patient with history of recurrent H.pylori gastiritis undergoes anaphylaxis after blood transfusion. What is most likely etiology?

Answer 4

selective IgA deficiency

• hint: recurrent mucosal infection. Blood transfusion with IgA gives anaphylaxis. Patients must be given blood without IgA

Question 5

Autoimmune polyendocrine syndrome-1

• defective gene
• phenotypes (3)

Answer 5

• defect in AIRE gene
• phenotypes
  1. hypoparathyroidism (hypocalcemia)
  2. adrenal insufficiency
  3. chronic mucocutaneous candidasis
• don’t get confused with DiGeorge (which also has hypoparathyroidism)

Question 6

Which immunodeficient disease presents with albinism?

Answer 6

Chediak-Higashi syndrome

Question 7

Which recombinant cytokine can be used to treat thrombocytopenia?

Answer 7

oprelvekin (IL-11)

: induces megakaryocyte maturation

Question 8

What is target of Cyclosporine and tacrolimus? what is function of this protein?

Answer 8

calcineurin

calcineurin is PHOSPHATASE that dephosphorylates
p-NFAT to NFAT, active form that works as transcription factor of IL-2