USMLE Road Map by Dr. Parmely

Question 1

What is the role of IFN-alpha and IFN-beta?

Answer 1

Blocking virus replication within cells

Question 2

What is the role of INF-gamma?

Answer 2

Potent activator of macrophages for killing of intracellular bacteria or fungi

Question 3

What is the role of mucocilliary movement in the lung epithelium and peristalsis of GI tract involvement in the immune system?

Answer 3

These move microbes and other foreign agents across mucosal surfaces and out of the body

Question 4

After the microbe is uptaken and subsequent fusion with a lysosome yields what?

Answer 4

Phagolysosome

Question 5

Chronic granulomatous disease is caused by a mutation in what?

Answer 5

NADPH oxidase - leads to problems with the oxidative burst

Question 6

What are the main functions of TNF-alpha?

Answer 6

Fever, leukocyte adhesion to endothelium, acute phase protein synthesis, oxidative burst, disseminated intravascular coagulation and shock

Question 7

What are the main functions of IL-6 and IL-1?

Answer 7

Fever, leukocyte adhesion to endothelium, acute phase protein synthesis and B lymphocyte co-activation

Question 8

IFN-alpha and beta have what role against viruses?

Answer 8

Blocking viral replication within cells

Question 9

What is the role of IFN-gamma?

Answer 9

Activation of macrophages for the killing of intracellular bacteria and fungi

Question 10

What is the role of CRP?

Answer 10

Binding to bacterial surface and activation of complement, serves as an opsonin

Question 11

What is the cause of the ESR in response to inflammation?

Answer 11

Increased fibrinogen

Question 12

Patients with hereditary angioedema have what?

Answer 12

Significantly decreased levels of plasma C1 inh, which is an important regulator of the classical pathway

Question 13

Complement peptide C3d binds to what?

Answer 13

B cell coreceptor CR2

Question 14

Can severe congenital neutropenia be treated with G-CSF?

Answer 14

No, this is a defect in the receptor for G-CSF

Question 15

What is interesting about a patients thymus with DiGeorge’s syndrome?

Answer 15

Patients with DiGeorge syndrome lack a thymus

Question 16

Where are B cells concentrated in lymph nodes?

Answer 16

Primary and secondary follicles within the cortex of lymph nodes

Question 17

Where do memory B cells develop in the LN?

Answer 17

Germinal centers of the cortex

Question 18

Where are T cells located in the LN?

Answer 18

Primarily in the paracortex where they associate with DCs

Question 19

Secreted antibodies exit the lymph node via?

Answer 19

Efferent lymphatics

Question 20

Use of the invariant chain is associated with what MHC class presentation?

Answer 20

MHC class II presentation

Question 21

Use of TAP protein is associated with what MHC class presentation?

Answer 21

MHC class I

Question 22

Patient presents with sever lymphopenia. Flow cytometry demonstrates low number of CD3 lymphocytes but normal IgM. What could be the disease?

Answer 22

DiGeorge Syndrome

Question 23

What two clinical abnormalities would be associated with a defective CD18 protein?

Answer 23

Defective leukocytosis and recurrent bacterial infections.

Question 24

A patient presents with lymphocytosis and enlarged lymph nodes. 90 percent of the patients bone marrow cells stain with CD3. What is a possible diagnosis?

Answer 24

T cell leukemia

Question 25

What is the best explanation for the reason that patients with antibody deficiencies can often present with the same types of infections as patients with phagocytic cell deficiencies?

Answer 25

Antibodies are important opsonins that promote microbe recognition by phagocytes

Question 26

What is a Coombs test?

Answer 26

To determine if an anemia has an immune basis by determining whether IgG antibodies are present on the patients erythrocytes

Question 27

What is the primary benefit of IVIG?

Answer 27

In immunodeficient patients it is to provide protection against extracellular microbial pathogens or their toxic products

Question 28

Dimeric IgA is associated with what?

Answer 28

Intestinal mucosa and is translocated across the mucosal epithelium. This is made possible by the secretory component

Question 29

What mediates opsonic activity of IgG antibodies?

Answer 29

The Fc fragment on antibodies bindgs to the Fc receptor on phagocytic cells

Question 30

RAG1/2 is responsible for what?

Answer 30

VDJ recombination

Question 31

Mutations in Rag1 or Rag2 genes lead to what disease?

Answer 31

SCID - characterized by a T-B-NK+ lymphopenia.

Question 32

What is allelic exclusion?

Answer 32

When successful rearrangement at one allele is achieved a signal is created that inhibits further rearrangements at the homologous allele

Question 33

If both alleles fail to productively rearrange what will happen?

Answer 33

They will most likely undergo apoptosis

Question 34

In order to generate junctional diversity nucelotides are added by what enzyme?

Answer 34

TdT

Question 35

Patient presents with recurrent bacterial infections that come back a week after finishing antibiotics. Lab test show mild neutropenia, low levels of IgG and IgA, and increased levels of IgM. When given a vaccination they make no detectable IgG. What could be the underlying cause of this?

Answer 35

Failure of her B cells to undergo Ig class switching.

Question 36

A population of plasma cells from a patient who was recently immunized with a protein vaccine has been isolated. Her cells secrete IgG but lack membrane IgG. What accounts for this?

Answer 36

Differential RNA processing favors the synthesis of a secreted form of gamma-heavy chains

Question 37

Th1 cells have a role in?

Answer 37

Cytokine production that is primarily associated with cell-mediated immunity; cytotoxic T cell growth and macrophage activation

Question 38

Th2 cells have a role in?

Answer 38

Production of cytokines that is primarily associated with humoral immunity; B cell activation, proliferation and differentiation and Ig class switching

Question 39

IL-4 induces what Th response?

Answer 39

IL-4 induces Th2 response

Question 40

IFN-gamma is an important inducer of what Th response?

Answer 40

Th1 response

Question 41

What is the transcription factor responsible for Th1 development?

Answer 41

T-bet responds to IFN-gamma promoting Th1 development

Question 42

What transcription factor is responsible for Th2 development?

Answer 42

GATA-3 activation leads to Th2

Question 43

Patient was given cyclosporine following organ transplant. 3 wks later patient developed a cytomegalovirus infection. A decrease in what response would be the best explanation for this opportunistic infection?

Answer 43

Cyclosporine inhibits the phosphatase calcineurin - important in activating NFAT. NFAT regulates cytokine genes in T cells including those that coinduce virus specific CD8 T cells to differentiate.

Question 44

If you were to design an experimental therapy directed at reducing cytokine production in allergic responses what would be a good target for this?

Answer 44

IL-4 It plays a central role in the development of allergy by promoting class switching to IgE and inducing more Th2 cells to produce IL-4

Question 45

Is Lck involved in TCR or BCR signaling?

Answer 45

TCR

Question 46

What is the TCR signaling pathway?

Answer 46

Lck phosphorylates ITAMs (zeta chains) leading to ZAP-70 then PLC-gamma-1 Louise inhabits zoo prohibitly

Question 47

What is the BCR signaling pathway?

Answer 47

Lyn - ITAMs (Ig-alpha and beta) - Syk - Btk - PLC-gamma-2 Lonnie I Sick Because Pineapple