Immune System

Question 0

IL-2

Answer 0

stimulates T cell growth, and activates NK cells

From T cells

Question 1

IL-1

Answer 1

Fever
Acute inflammation, chemokine secretion

From macrophages

Question 2

IL-3

Answer 2

Stimulates growth & differentiation of cells in BONE marrow

From T cells

Question 3

IL-4

Answer 3

Induce Th2 differentiation & B cell growth/switching

From Th2 cells

Question 4

IL-5

Answer 4

B cell growth & switch to IgA, & eosinophils

From Th2 cells

Question 5

IL-6

Answer 5

Fever & acute phase proteins

From macrophages & Th2 cells

Question 6

IL-10

Answer 6

ANTI-inflammatory!
Inhibits activated T cells & Th1 cells

From Th2 cells & Tregs

Question 7

IL-8

Answer 7

Neutrophil chemotaxis

From macrophages

Question 8

IL-12

Answer 8

Differentiation of T cells to Th1 cells, activate NK cells

From macrophages & B cells

Question 9

TNF-alpha

Answer 9

Septic shock! Activates endothelium
Also insulin resistance

From macrophages

Question 10

INF-gamma

Answer 10

*anti-viral & anti-tumor!
Activates macrophages & Th1 cells, inhibit Th2 cells

From Th1 cells

Question 11

Case: Young child > 6 mo. old w/ recurrent bacterial infections, low # B cells, and low Igs of all classes.

Answer 11

“Bruton’s Agammaglobulinemia;” X-linked Recessive.
tyrosine kinase gene defect –> no B cell maturation
=> no opsonization

Question 12

Case:

Patient has anaphylaxis to blood transfusion, also some Hx of sinopulmonary infections & chronic GI infections.

Answer 12

Selective IgA deficiency. *common.
LOW IgA, but normal IgM & IgG.
* anaphylaxis to transfusion bc contained IgA!
*may have false-positive beta-hCG tests (has heterophile Ab)

Question 13

Case:

Age 20-30, recent increase in sinopulmonary infections. Low plasma cell on work-up.

Answer 13

“CVID” = Common Variable ImmunoDeficiency
(mech unknown, can be acquired as young adult)
B cell maturation defect -> normal # B cells but low plasma cells & Ig
* increased risk auto-immune disease

Question 14

DiGeorge Syndrome

Answer 14

22q11 del. => fail to form 3rd & 4th pharyngeal arches

1. tetany (hyperCa2+ bc missing parathyroids)
2. recurrent fungal or viral infections (T cell def bc thymus aplasia)
3. congenital heart and great vessel defects

Question 15

Cause of disseminated mycobacterial infections

Answer 15

IL-12 deficiency –> decreased Th1 response => low IFN-gamma

Question 16

Case:
Patient with…
1. Coarse Facies, 2. cold/non-inflamed staph abscesses
3. retained primary teeth, 4. eczema, 5. high IgE

Answer 16

Hyper-IgE syndrome/Job’s Syndrome

= failure to produce IFN-gamma => neutrophils can’t respond to chemotactic stimuli

Question 17

2 causes of SCID (Severe Combined Immunodeficiency)

Answer 17

1. defective IL-2 (X-linked Recessive)
2. Adenosine DeAminase def. (AR)
   => failure to thrive bc recurrent serious infections of all kinds
   * absent germinal centers & T cells

Question 18

Patient presents w/ this triad:

1. cerebellar defects/ataxia
2. spider angiomas
3. IgA deficiency

Answer 18

= Ataxia-Telangiectasia
(ATM gene mut –> DNA repair problem)
*increased AFP

Question 19

Case: patient presents w/...
1. thrombocytopenic purpura
2. eczema
3. recurrent pyogenic infections
tests show: high IgA & IgE, low IgM

Answer 19

Wiskott-Aldrich Syndrome (WAS mut., X-linked).
= T cells can’t recognize actin skeleton

• risk inf. by: N meningitis, H influ, Strep pneumo, PCP

Question 20

Case:

Infant w/ recurrent bacterial infections but NO pus formation. Also had slow healing umbilical stump.

Answer 20

LAD-1 (Leukocyte Adhesion Deficiency)
= defect in LFA-1 => lymphocytes can’t migrate INTO tissues
(diapedesis blocked)
* also: neutrophilia.

Question 21

Case:
Patient w/ recurrent staph & strep infections.
Other Hx: partial albino & peripheral neuropathy

Answer 21

Chediak-Higashi Syndrome (AR)
= Lysosomal trafficking gene mut
–> lysosome-phagosome fusion problem.
*giant granules in neutrophils

Question 22

patient w/ lack of NADPH oxidase.

Disease = __?__

Answer 22

= Chronic Granulomatous Disease,
–> granulomatous skin lesions
*increased risk infection w/ catalase + organisms
(Staph aureus, E. coli, aspergillus)

Question 23

positive selection (B & T cells)

Answer 23

only cells that recognize self-MHC survive

Question 24

Negative selection (B & T cells)

Answer 24

cells that react to self-Ag killed (prevent autoimmune rxns)

Question 25

BCR vs. Antibody

Answer 25

same function (bind antigens)... But:
BCR = attached to plasma membrane, w/ transmembrane segment
Antibody = secreted from plasma cells (NO transmembrane domain)

Question 26

CD4 T Cells = “helpers” bc…?

Answer 26

• Help activate APCs (via CD40L)
• Help CD8 cells (IL-2 expression)
• Help B cells (CD40L, increase activation, etc.)

Question 27

Congenital triad for Toxoplasmosis

Answer 27

(from cat feces, risk mostly to pregnant women bc…)
congenital toxoplasmosis =
1. chorioretinitis
2. hydrocephalus
3. intracranial calcifications
=> to protect fetus, Tx mother w/ sulfadiazine & pyrimethamine!!

Question 28

Live attenuated virus vaccines:

Answer 28

Smallpox
Yellow Fever
VZV (chicken pox)
Sabin Polio vaccine
MMR
influenza (intranasal)

Question 29

E Coli Virulence factors (5)

Answer 29

1. Lipid A (LPS): TNF-a => fever, IL… => shock
2. K1 capsular polysacch: –l phagocytosis & cmplmt…=> meningitis!
3. P fimbriae: adhesion to uroepithelium => UTIs
4. Heat labile/stable toxins: fluid & electrolyte secretion => diarrhea
5. verotoxin: –l 60S ribosome = –l protein synth => bloody diarrhea