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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. What are the autoantibodies for sjorgens syndrome?
MHC class molecules bind to KIRS or CD94 to prevent killing
Anti SS- A (anti RO) and Anti SS- B
IgG
Scratch test - histamine mediated wheal; radioimmunosorbent assay (detects specific IgEs in serum)

2. What lymph node drains the anal canal (below the pectinate line)?
Stimulate the liver to release acute phase reactants
Paracortex; viral infection
Superficial inguinal
HBV - HBC - Kaposis - leukemias - malignant melanoma - hairy cell leukemia and condyluma accuminata

3. What is the white pulp of the spleen?
A B and T cell disorder; defect in DNA repair enzymes; ataxia - telangactasia and IgA def; igA def. and increased AFP
Anti topoisomerase
Lack of NADPH oxidase results in a lack of respiratory burst in neutrophils; susceptibility to catalase positive organisms (S. aureus - E. Coli - Aspergillus)
Surrounds the red pulp and begins with PALS and then turns into follicles with B cells/follicles

4. The alternative pathway is the only constutively...
T cells react to the angtigen and activate leukocyted (macrophage acitivation)
N. meningitidis - H. influenzae - S. pneumonia - Salmonella d/t lack of C3b opsonization for MAC d/t lack of complement activation d/t lack of IgM; MAC is needed by encapsulated avoid by humoral and cell mediated through their capsule
active complement pathway
P - ANCA (antimyeloperoxidase); in neutrophil; p= perinuclear

5. What is colostrum?
N. meningitidis - H. influenzae - S. pneumonia - Salmonella d/t lack of C3b opsonization for MAC d/t lack of complement activation d/t lack of IgM; MAC is needed by encapsulated avoid by humoral and cell mediated through their capsule
The igA found in breast milk
Monoclonal Ab to CD3- blocks cellular transduction and signaling of T cells
Ischemia and necrosis of graft due to occlusion of vessels and fibrinoid necrosis and thrombosis within the vessels

6. Type IV hypersensitivity is i...
IgE
MHC class molecules bind to KIRS or CD94 to prevent killing
not Ab mediated
Surrounds the red pulp and begins with PALS and then turns into follicles with B cells/follicles

7. Which TCR MHC system is important for viral immunity? neoplastic? donor graft cells?
Glycoproteins; HLA
All MHC 1/CD8
Previous transfusion; pregnant woman whose fetus had paternal antigens
IL 3; supports growth and differentiation of bone marrow stem cells

8. What type of fenestrations are found in the red pulp of the spleen?
Cyclosporine - OKT3
Lack of NADPH oxidase results in a lack of respiratory burst in neutrophils; susceptibility to catalase positive organisms (S. aureus - E. Coli - Aspergillus)
carboxy terminal
Barrel hoop basement membrane fenestrations

9. For which toxins are preformed antibodies (passive) given?
Tetanus - Botulinum - HBV - Rabies
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
Anti TSh receptor
IgE; by activating eosinophils

10. Which are the only two antiinflammatory cytokines?
Antiviral for uninfected cells (for future protection) and kills virally infected cells (NK activation)
TGF beta and IL 10
If there is class switching and plasma cell production (that is when memory cells are produced)
In the germinal center of secondary follicles (In the paler center)

11. IgG...
C5a
Septicemia with neisseria; because at least you have C3 to act like a neutrophilic chemotactic and an acute phase reactant
opsonizes
Activate B cells - activate Macrophages - kill viruses directly - delayed cell mediated hypersensitivity - acute and chronic rejection

12. Name three things that IL 1 does as a cytokine. other than the liver - who secretes IL 1
Induces fever - chemokine secretion to recruit - activates adhesion molecules; macrophages
Antibody mediated cytotoxicity; either complement dependent or complement independent
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
Inferior mesenteric

13. What is a factor that is a predictor for a bad transplantation?
Inferior mesenteric
IgAs in mothers breast milk!
Patient has had previous exposure to blood products which result in presence of preformed anti HLA cytotoxic Abs
Axillary

14. which antibodies can bind complement?
Some microbial surfaces (only) have mannan binding lectin which activates a protease that cleaves C2 and C4 which combine to make C3. the rest follows the alternative pathway
No because no peptide fragment!
IgM and IgG
isotype

15. What lymph node drains the stomach?
DM type I
Previous transfusion; pregnant woman whose fetus had paternal antigens
Celiac
IgM and IgA

16. give an example of how influenza does a major antigenic shift.
Acts as second signal on B cells to induce class switching to IgA; also stimulates eosinophils
opsonizes
RNA segment reassortment
Yes

17. The Fc region is found on the...
acute phase reactants
carboxy terminal
Periarteriolar lymphatic sheath in the white pulp that surround that dead end of the capillaries in the red pulp - contain T cells
Lack of NADPH oxidase results in a lack of respiratory burst in neutrophils; susceptibility to catalase positive organisms (S. aureus - E. Coli - Aspergillus)

18. What are the three types of APCs?
Cytokine IL 10 secreted by Th2
AR; defect in MT function results in decreased transport and phagocytosis; recurrent pyogenic infections by staphylococci and streptococci - partial albinism - and peripheral neuropathy
Psoriasis - Ankylosis Spondylitis - IBD - Reiters; all seronegative spondylopathies
Macrophages - Dendritic cells - B cells

19. If the alternative pathway is constitively active - how come normal cells don't get attacked with MAC?
Paracortex; viral infection
Aut. Dominant; C1 esterase inhibitor deficiency resulting in continued C1 which results in increased C2 and C4 cleavage products which have anaphyltoxic activity and result in swelling of face and oropharynx
DAF and C1 esterase inhibitor on cells prevent complement activation on their surfaces (microbial surfaces lack this)
Defect in BTK a tyrosine kinase gene; failed maturation of B cells; X linked recessive

20. All transplant rejections - _____________ are mediated by Type IV hypersensitivity
IL 4 - 5 - 10 - 6
pentamer
pathogenesis
except hyperacute

21. In thymic development - What is the positive selection? negative selections?
When you select for which MHC it will have; take out the lymphs that self react
MS - hay fever - SLE - goodpastures
IL 4
Liver! (they are proteins circulating in the blood)

22. IgM can fix complement but...
Histamine (causes vasodilation) - leukotrienes (causes bronchoconstriction) - chemotaxins for eos - and heparin (increased blood flow needs to be anticoagulated!)
Some microbial surfaces (only) have mannan binding lectin which activates a protease that cleaves C2 and C4 which combine to make C3. the rest follows the alternative pathway
Anti SS- A (anti RO) and Anti SS- B
cannot cross placenta

23. How is the antigen loaded onto a MHC II?
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
MHC II/CD4 and B7 (on APC) and CD28 (on Th cell); releases cytokines to kill those extracellular buggers!
Viral neutralization of igM and IgG!
Ig - CD19 - CD20 - CD21 - CD40 - MHC II - B7

24. What are the three immune privileged sites? why are they called that? what happens after infection in these areas?
Influenza; antigenic shift; antigenic drift
For some reason a mature naive B lymphocyte got away from tolerance and the result was a production an Ab on its surface with an Fab region that recognized the alpha 3 collagen subunit on the BM as non self. It then gets activated by a Th2 cell (enti
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
Immunoflourescent staining of tissue biopsies

25. Which diseases are associated with DR5?
Pernicious Anemia and Hashimotos
Barrel hoop basement membrane fenestrations
N. meningitidis - H. influenzae - S. pneumonia - Salmonella d/t lack of C3b opsonization for MAC d/t lack of complement activation d/t lack of IgM; MAC is needed by encapsulated avoid by humoral and cell mediated through their capsule
Type IV

26. Which disease is associated with DR7?
T cell activation; no with CD 4 or CD 8
Defect in BTK a tyrosine kinase gene; failed maturation of B cells; X linked recessive
Severe pyogenic infections early in life
Steroid responsive nephrotic syndrome

27. what results in symptoms of shock in an acute hemolytic transfusion reaction?
Hours later (instead of minutes); instead of release of preformed mediators - mast cells synthesize PGs and LTs that mediate the late phase reaction (edema - inflammation - decreased airflow)
Make antibody - allergy type 1 (igE) - Cytotoxic and immunecomplex hypersensitivity type II and III (igG); hyperacute organ rejection is Ab mediated
Antiviral for uninfected cells (for future protection) and kills virally infected cells (NK activation)
Since it is a comp dependent type II hypersensitivity reaction; C3a brings anaphylotoxins that bring in mediators of shock

28. How do you test for type III hypersensitivity?
Immunoflourescent staining of tissue biopsies
Carbohydrate
The antibodies (igM or IgG) either neutralize the target directly (cytoxic!) or recruit leukocytes (Neutrophils and Macrophages!) to incite tissue damage
Anti TSh receptor

29. which interleukin receptor is required for NK development? activation?
IgG
T cells react to the angtigen and activate leukocyted (macrophage acitivation)
Mediates septic shock; activates the endothelium for adhesion and dilation and leukocyte recruitment results in vascular leak
IL 15; IL 12 - interferon Beta and interferon alpha

30. which immunodeficiency presents with delayed separation of the umbilicus? ataxia? telangiectasia?albinism? anaphylaxis on exposure to blood products with IgA? tetany?retained primary teeth? peripheral neuropathy?
Cytokine release syndrome due to initial release from initial binding (fever etc) and hypersensitivity reaction
Defect in B cell maturation; idiopathic - presents at older age and normal number of B cells and hyperplastic germinal centers because B cells can be activated but can not produce Abs
Leukocyte adhesion defect; ataxia telangietasia; ataxia telangiectasia; chediak higashi syndrome; IgA def; Digeorge syndrome; Jobs; Chediak Higashi
Anti TSh receptor

31. give an example of a virus that uses antigenic variation. What does a major variation result in? minor?
Influenza; antigenic shift; antigenic drift
Mycobacterium Tuberculosis - Mycobacterium Avium Intracellulare; Toxoplasmosis Gondii
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
Lymphocytes

32. Type Iv hypersensitivity is...
Antigliadin - antiendomysial (both are IgAs - anti tissue transgluataminase igA)
MS - hay fever - SLE - goodpastures
cannot cross placenta
delayed!

33. What is the pathology in hyperacute transplant rejection?
Complement activation (active in both)
Ischemia and necrosis of graft due to occlusion of vessels and fibrinoid necrosis and thrombosis within the vessels
T cells react to the angtigen and activate leukocyted (macrophage acitivation)
Anemias (esp due to renal failure)

34. What is MHC I made out of? Where is it found? What does it bind to? What type of antigens does it present?
An alpha chain and a B2 microglobulin; on all nucleated cells; TCR and CD8; intracellular antigens
IgG and IgM bind to pathogens activating C1 convertase and leads to C2 and C4 and then C3 convertase activated
No! That is why they are different from T cells - they can recognize antigens in free solution; if a bug has a peptide fragment that a mature naive B cell recognizes it will bind to it and cause activation - it then gets activated into a plasma cell!
Immunoflourescent staining of tissue biopsies

35. What is the result of an IL 12 deficiency? What is the presentation? What are the labs?
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
Antiviral for uninfected cells (for future protection) and kills virally infected cells (NK activation)
Decreased Th1 response; disseminated mycobacterial infections; decreased interferon gamma
False! B cell class switching requires a second signal

36. Which diseases are associated with DR4?
DM type I and RA
lowest concentration
secondary
An alpha chain and a B2 microglobulin; on all nucleated cells; TCR and CD8; intracellular antigens

37. What does interferon gamma do? What two type of cells does it attack mostly?
IgM and IgA
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
Activates Macrophages and Th1 cells; suppresses Th2 cells; antiviral and antitumor
DAF and C1 esterase inhibitor on cells prevent complement activation on their surfaces (microbial surfaces lack this)

38. What are the main symptoms of T cell immunodeficiencies?
Tetanus - Botulinum - HBV - Rabies
Steroid responsive nephrotic syndrome
except hyperacute
Intracellular pathogens (acute and chronic viruses and virally induced cancers)

39. which of the transplant rejections is antibody mediated? why does it occur?
Hyperacute; presence of preformed antibodies in the recipient ( to blood groups or HLA )
SP infections
Tetanus - Botulinum - HBV - Rabies
A recomb cytokine of IL 2; RCC and metastatic melanoma

40. Complements are...
acute phase reactants
Since it is a comp dependent type II hypersensitivity reaction; C3a brings anaphylotoxins that bring in mediators of shock
Barrel hoop basement membrane fenestrations
Fibrosis of blood vessels and graft tissue from ischemia; obliterative vascular fibrosis with intimal thickening

41. What are the cell surface proteins for Macrophages? which two are for opsonins?
Antigliadin - antiendomysial (both are IgAs - anti tissue transgluataminase igA)
MHC II - B7 - CD40 and CD14; CD40 and D14 for FcG and C3b resp
Defect in B cell maturation; idiopathic - presents at older age and normal number of B cells and hyperplastic germinal centers because B cells can be activated but can not produce Abs
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

42. What type of cells do NK cells attack? with What tools? by necrosis or apoptosis?
Tumor cells and virally infected cells; perforin pore to secrete granzymes through it; apoptosis
Kill them because they have CD16 on them that recognize the FcG portion
Opsonize bacteria (for enhanced phagocytosis) - neutralize viruses (igG) - activate complement (igM and igG) - sensitize mast cells (igE)
T cell precursor

43. What does IL 4 do?
Antidote for digoxin intoxication
Acts as second signal on B cells to induce class switching to IgE and IgG
Antimicrosomal and antithyroglobulin
Anticentromere; anti Scl -70 (anti DNA topoisomerase I)

44. What are HEV? Where are they found? Where does the vasculature of the lymph node travel to?
Normal pro B (CD 19 +) - no mature B cells results in decreased total B cell level - and decreased amount of immunoglobulins in each class
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
Activates Th1 helper cells; Macrophages
Antihistone

45. can igG cross the placenta?
All MHC 1/CD8
Digeorge syndrome - 22q11 deletion resulting in failure to develop 3rd and 4th pharyngeal pouches; cardiac and great vessel congenital defects - tetany from hypocalcemia - recurrent viral/fungal infections from T cell deficiency; hypoPTH - hypoCa - a
Anti viral and anti tumor
Yes

46. which antibody activate mast cells - basophils - and eosinophils?
IgG
Vasculitis of graft vessels with dense interstitial lymphocytic infiltrate; yes! with immunosuppressants
IgE
A - B - C; all the D's

47. What are the main cell surface proteins on B cells?
Superficial inguinal
pentamer
Ig - CD19 - CD20 - CD21 - CD40 - MHC II - B7
T

48. What are the autoantibodies for hashimotos?
Ig - CD19 - CD20 - CD21 - CD40 - MHC II - B7
Barrel hoop basement membrane fenestrations
T
Antimicrosomal and antithyroglobulin

49. What are the three types of lymphocytes?
B - T - and NK cells
Hyperacute; presence of preformed antibodies in the recipient ( to blood groups or HLA )
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
IL 5

50. So antibodies are the effectors for the humoral response. List some of their functions.
Cross link antigens which increases their phagocytability; activate complement for MAC attack; opsonization; neutralization
Kill them because they have CD16 on them that recognize the FcG portion
IL 1 and IL 6
CGD; Jobs syndrome (defect in Neutrophil chemotactic response)