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USMLE Step 1 Immunology

Subjects : health-sciences, usmle-step-1

Instructions:

Answer 50 questions in 15 minutes.
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Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. How is the thymus organized? what happens in each section?
Interferon gamma; Th1
Cyclosporine and tacrolimus; sirolimus (as well as hyperlipidemia)
Into cortex and medulla; cortex is where immature T lymphocytes enter - at the corticomedullar junction is where positive and negative selection occur; and at the medulla is where the mature T lymphs - reticulin cells and hassalls corpuscles are (dea
Graves

2. Name two endogenous pyrogens
Glycoproteins; HLA
Activate B cells - activate Macrophages - kill viruses directly - delayed cell mediated hypersensitivity - acute and chronic rejection
IL 1 and IL 6
MS - hay fever - SLE - goodpastures

3. What lymph node drains the rectum (above the pectinate line)?
Macrophages - Dendritic cells - B cells
DM type I
Internal iliac
Activates Th1 helper cells; Macrophages

4. What are the autoantibodies for Mixed connective tissue disease?
Anti U1 RNP (ribonucleoprotein)
acute phase reactants
An acidified endosome with the antigen fuses with the MHC which causes the release of the invariant chain Which is sitting in spot of antigen and stabilizing the MHC II
Yes

5. What is Aldesleukin? What is it used for
A recomb cytokine of IL 2; RCC and metastatic melanoma
Edema and necrosis in that region
Influenza; antigenic shift; antigenic drift
Not thymus - BM

6. IgM can fix complement but...
Hemochromatosis
cannot cross placenta
Receiving preformed Antibodies
An acidified endosome with the antigen fuses with the MHC which causes the release of the invariant chain Which is sitting in spot of antigen and stabilizing the MHC II

7. The ______ in the BM are DN - the DP are in the cortex of thymus
Anti alpha subunit 3 of collagen on type IV bm
Antidote for digoxin intoxication
Ig - CD19 - CD20 - CD21 - CD40 - MHC II - B7
T cell precursor

8. The two heavy chains of an antibody contribute to the...
Histamine; post capillary venules - vasodilation
dimer
Fab portion
C5a

9. Name three things that IL 1 does as a cytokine. other than the liver - who secretes IL 1
Anti TSh receptor
Antiviral for uninfected cells (for future protection) and kills virally infected cells (NK activation)
Induces fever - chemokine secretion to recruit - activates adhesion molecules; macrophages
MHC II - B7

10. What lymph node drains the scrotum?
IgG
No because no peptide fragment!
False! B cell class switching requires a second signal
Superficial inguinal

11. describe the classic complement pathway.
IgG and IgM bind to pathogens activating C1 convertase and leads to C2 and C4 and then C3 convertase activated
Antimicrosomal and antithyroglobulin
Brain - eyes - placenta/fetus - testicles; because they can have an antigen in there and not get attacked by immune system because dont have contact with immune system via blood and lymph; if an infection occurs such that trauma results in exposure t
delayed!

12. Name 5 ways Antibody diversity is generated?
In any situation where immunologically competent cells are transplanted into immunologically crippled recipient; graft rejects all the cells due to foreign proteins resulting in severe organ dysfunction
IgM and IgD
1) VJ light chain random creation 2) VDJ (heavy chain) random creation 3) random combination of light with heavy 4) somatic hypermutation (high frequency mutating that occurs on activation) 5) terminal deoxynucleotidyl transferase (TDT) random additi
Paracortex; viral infection

13. what happens in order for class switching to occur (after being activated by IL and cd40 L)?
Alternative splicing of mRNA
The red pulp of the spleen its where the vasculature channels go through and interact with the parenchyma of the spleen (has macrophages) which empty in the sinuses; they are both encapsulated (with trabeculae) secondary lymphoid organs that trap ant
Hereditary angioedema; PNH
CRP - C3b - IgM

14. What are the two signals required for T cells? what happens after?
Scratch test - histamine mediated wheal; radioimmunosorbent assay (detects specific IgEs in serum)
MHC I/CD8 and IL2/IL 2 Receptor (IL 2 is from Th1!); cytoxicity!
Cell mediated due to T cell cytotoxicity reacting to foreign MHCs; few weeks after
Activate macrophages

15. What are the autoantibodies for pernicious anemia?
DM type I and RA
Anti IF
Anti glutamate carboxylase and anti insulin
cannot cross placenta

16. What are target cells?
In IgE AIHA- it results in MAC attack (remember IgE is not an opsonin!) - in IgG AIHA C3b (and IgG) opsonization results in phagocytosis by fixed macrophages in the spleen
Cells that stil have weird parts of their membrane that macrophages usually bite off
Previous transfusion; pregnant woman whose fetus had paternal antigens
An anaphylactic immediate reaction; atopy refers to the inherited propensity to develop asthmatic or allergic reactions

17. What is MHC II made out of? Where is it found? What does it bind to? What type of antigens does it present?
acute phase reactants
Not thymus - BM
MAC (membrane attack complex) Which is activated by C5b - C9 and results in lysis and cytoxicity by creating pores in the target membrane; encapsulated organisms (S. pnuemonia - H.influenzae - B perfussis for example) and other organisms with non pep
An alpha and beta chain; only on APCs; TCR and CD4; extracellular (phagocytosed by APCs)

18. A lymph node is a ________ lymphoid organ.
IgM and IgA
secondary
CD56
Remove encapsulated bacateria

19. How is i Th1 helper cell inhibited?
Immunoflourescent staining of tissue biopsies
Both decrease cd8 tcell prolif but one through mtor and the other through calcineurin (resp)
Cytokine IL 10 secreted by Th2
A - B - C; all the D's

20. What is anergy? why does this occur?
Adenosine deaminase deficiency (AR) - defective IL 2 receptor (X linked) - and failure to synthesize MHC II; both humoral and cell mediated deficiency
NK cells
Lack of response from lymphocytes when activated; because they are self reactive - this is a form of tolerance
Type III hypersensitivity where an internal antigen antibody complexes activate classical complement pathway resulting in C3a neutrophilic chemotaxis and neutrophilic lysosomal death. SLE

21. Describe the complement independent Type II hypersenstivity reaction. Give an example.
Remove encapsulated bacateria
neutrophilia!
IL 4
The antibodies (igM or IgG) either neutralize the target directly (cytoxic!) or recruit leukocytes (Neutrophils and Macrophages!) to incite tissue damage

22. What are the autoantibodies for primary biliary cirrhosis?
Normal pro B (CD 19 +) - no mature B cells results in decreased total B cell level - and decreased amount of immunoglobulins in each class
Anti mitochondrial
Yes
Active; passive - fast but short half life (3 weeks!)

23. What are the labs in brutons agammaglobulinemia?
The red pulp of the spleen its where the vasculature channels go through and interact with the parenchyma of the spleen (has macrophages) which empty in the sinuses; they are both encapsulated (with trabeculae) secondary lymphoid organs that trap ant
Coarse Faces - cold (noninflamed d/t inability to attract neutrophils) staph abscesses - retained primary teeth - high igE - dermatologic problems (eczema)
Closed circuit where go directly to veins and open where squeeze out of capillary sinusoids and interact with either PALS or with macrophages in the cords of Billroth (for antigen immune function or for blood cleaning or for both) and squeeze back in
Normal pro B (CD 19 +) - no mature B cells results in decreased total B cell level - and decreased amount of immunoglobulins in each class

24. Which HLA's are included in MHC I? MHC II?

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25. What are four results of a splenectomy?
Since cant cross placenta most likely means that child was forced early to produce due to an infection (most likely CMV)
1) susceptibility to encapsulated organisms 2) Howell Jolly Bodies 3) Target cells 4) Thrombocytosis
T cell dysfunction
IL 3; supports growth and differentiation of bone marrow stem cells

26. where are complements produced?
Activate macrophages
Anti nuclear Antibodies (ANA); Anti dsDNA - anti Smith
Liver! (they are proteins circulating in the blood)
They directly stimulate Macrophages by binding CD14; also the alternative complement pathway binds to these host surfaces and induces MAC complex; also TLRs exist for endotoxins; also IgM though not an opsonin can act as a pentamer and trap the antig

27. What are the two signals required for Th1 cells? what happens after then activated?
Immunoflourescent staining of tissue biopsies
MHC II/CD4 and B7 (on APC) and CD28 (on Th cell); releases cytokines to kill those extracellular buggers!
A - B - C; all the D's
Steroid responsive nephrotic syndrome

28. Which disease is associated with DR7?
A chemotactic factor for neutrophils
Chronic granulomatous disease
A B and T cell disorder; X linked recessive; progressive deletion of B and T cells; thrombocytopenic purpura - infections - eczema; high IgE and IgA but low IgM
Steroid responsive nephrotic syndrome

29. What type of cells do NK cells attack? with What tools? by necrosis or apoptosis?
Lymphocytes
Make antibody - allergy type 1 (igE) - Cytotoxic and immunecomplex hypersensitivity type II and III (igG); hyperacute organ rejection is Ab mediated
Tumor cells and virally infected cells; perforin pore to secrete granzymes through it; apoptosis
Hyperacute; presence of preformed antibodies in the recipient ( to blood groups or HLA )

30. Other than stimulating fever - what else does IL 6 do?
Stimulate the liver to release acute phase reactants
Remove encapsulated bacateria
MHC II - B7 - CD40 and CD14; CD40 and D14 for FcG and C3b resp
Antimicrosomal and antithyroglobulin

31. which antibody is involved in the primary response or immediate response to an antigen?
IL 4
High endothelial venules are post capillary cuboidal endothelial cells that contain specific adhesion molecules for lymphocytes with specific binders that allows for lymphocytes to drain out of the vasculature into the lymph node structure (this is h
IgM
Edema and necrosis in that region

32. Which antibodies can be multimeric?
IgM and IgA
Since cant cross placenta most likely means that child was forced early to produce due to an infection (most likely CMV)
Immunosuppression after kidney transplantation
MAC (membrane attack complex) Which is activated by C5b - C9 and results in lysis and cytoxicity by creating pores in the target membrane; encapsulated organisms (S. pnuemonia - H.influenzae - B perfussis for example) and other organisms with non pep

33. What is the pathogenesis of chronic transplant rejection? When does it occur? is it reversible?
Delayed type hypersensitivity
Anti IF
T cell and antibody mediated vascular damage due to MHC non self being recognized as self by self lymphocytes and resulting in attack of the foreign antigens it presents (all of them); months to years after; no :(
Axillary

34. The Fc region is found on the...
Negative!
Anti Ach receptor
carboxy terminal
Give a vaccine with a peptide comp from it that the cell mediated immunity otherwise cant get to! like h.influenzae vaccine. then class switching and memory response can occur

35. What is wiskott aldrich syndrome? What is its mode of inheritance? What is the pathogenesis of disease? What is its triad of presentation? what labs does it present with?
A B and T cell disorder; X linked recessive; progressive deletion of B and T cells; thrombocytopenic purpura - infections - eczema; high IgE and IgA but low IgM
Monoclonal Ab to CD3- blocks cellular transduction and signaling of T cells
Recomb cytokine of GCSF (granulocyte macrophage colony stimulating factor; for recovery of bone marrow
DM type I and RA

36. What is the white pulp of the spleen?
not Ab mediated
Surrounds the red pulp and begins with PALS and then turns into follicles with B cells/follicles
Its main effect is a defect in Ab opsonization for killing
Intracellular pathogens (acute and chronic viruses and virally induced cancers)

37. What does granzyme do? who secretes it?
TLR ad nuclear receptors
Anti TSh receptor
Its a serine protease that activates apoptosis; NK and CD8
Bind FcG for antibody dependent cellular cytotoxicity

38. Describe the interstitial tissue of a spleen including the sinuses. What type of cells are found in the four structures (cortex - paracortex - medulla and sinuses)?
Axillary
The interstitial tissue of a lymph node is structured into the cortex on the outside Which is densely cellular which transitions into the paracortex Which is less dense and then the medulla Which is least dense. The cells that inhabit these tissues a
All MHC 1/CD8
Opsonization (Brutons agammaglobulinemia) - adhesion (Leukocyte adhesion defect) - phagocytosis (chediak higashi syndrome) - respiratory burst (chronic granulomatous disease)

39. What is the clinical use for azathioprine?
Remove encapsulated bacateria
Since cant cross placenta most likely means that child was forced early to produce due to an infection (most likely CMV)
A - B - C; all the D's
...

40. What is the main cytokine that activates eosinophils?
Lack of response from lymphocytes when activated; because they are self reactive - this is a form of tolerance
IL 5
Periarteriolar lymphatic sheath in the white pulp that surround that dead end of the capillaries in the red pulp - contain T cells
DM type I

41. What bugs can actually infect the lymph node itself?
Macrophages - Dendritic cells - B cells
Mycobacterium Tuberculosis - Mycobacterium Avium Intracellulare; Toxoplasmosis Gondii
The igA found in breast milk
Active; passive - fast but short half life (3 weeks!)

42. What does Interferon alpha and beta do? how?
They directly stimulate Macrophages by binding CD14; also the alternative complement pathway binds to these host surfaces and induces MAC complex; also TLRs exist for endotoxins; also IgM though not an opsonin can act as a pentamer and trap the antig
Antiviral by inducing ribonuclease which degrades only viral mRNA (prevents protein synthesis) and activates NK cells to kill virus infected cells
Th cells fail to produce interferon gamma; a lot of IgE
Patient has had previous exposure to blood products which result in presence of preformed anti HLA cytotoxic Abs

43. What portion of the lymph node is not well developed in DiGeorge Syndrome?
Acts as second signal on B cells to induce class switching to IgE and IgG
acute phase reactants
Proteins; IgG - IgM - endotoxin (microbial surfaces in general - nonspecific ones also) - mannose binding Lectin; classic - alternative - MB pathway (resp)
Paracortex

44. ________ regulate the cell mediated response.
Type III hypersensitivity where an exogenous antigen results in a systemic antigen antibody complex disease (takes around 5 days after exposure for the Abs to develop); immune complexes then fix in tissue and activate complement resulting in tissue d
Influenza; antigenic shift; antigenic drift
Humoral
Chronic granulomatous disease

45. What does IL 2 do?
Activates cytotoxic CD 8 T cells as second signal
Paracortex
In any situation where immunologically competent cells are transplanted into immunologically crippled recipient; graft rejects all the cells due to foreign proteins resulting in severe organ dysfunction
Immunosuppression after kidney transplantation

46. What are the autoantibodies for autoimmune hepatitis?
...
Anti smooth muscle
IL 15; IL 12 - interferon Beta and interferon alpha
Antihistone

47. which of the hypersensitivity reactions is not Ab mediated?
Type IV
Activates cytotoxic CD 8 T cells as second signal
IgG
The antibodies (igM or IgG) either neutralize the target directly (cytoxic!) or recruit leukocytes (Neutrophils and Macrophages!) to incite tissue damage

48. Which diseases are associated with DR4?
MHC II/CD4 and B7 (on APC) and CD28 (on Th cell); releases cytokines to kill those extracellular buggers!
Ischemia and necrosis of graft due to occlusion of vessels and fibrinoid necrosis and thrombosis within the vessels
DM type I and RA
In the germinal center of secondary follicles (In the paler center)

49. What is recomb alpha interferon used for?
Type II hypersensitivity - complement dependent resulting in phagocytosis of RBCs coated with C3b by fixed macrophages in the spleen; Group O mother has anti A - B - IgG Abs that cross placenta and attach to fetal blood group A or B RBCs
HBV - HBC - Kaposis - leukemias - malignant melanoma - hairy cell leukemia and condyluma accuminata
Negative selection
Maculopapular rash (palm - soles - back - neck) - jaundice with bile duct necrosis - hepatosplenomegaly - diarrhea; bone marrow and liver transplants (rich with lymphocytes); SCID patient receiving whole blood transfusion

50. What is the clinical use of Muromonab?
Antibody mediated cytotoxicity; either complement dependent or complement independent
IgE; by activating eosinophils
It is a localized type III hypersensitivity reaction to an external antigen; localized instead of systemic; ?; intradermal injection of the antigen results in antibody production and antigen antibody complexes deposit in the skin
Immunosuppression after kidney transplantation