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USMLE Step 1 Immunology

Subjects : health-sciences, usmle-step-1

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
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 does granzyme do? who secretes it?
Its a serine protease that activates apoptosis; NK and CD8
MHC II/CD4 and B7 (on APC) and CD28 (on Th cell); releases cytokines to kill those extracellular buggers!
...
Hyperacute; presence of preformed antibodies in the recipient ( to blood groups or HLA )

2. What is the presentation of common variable immunodef? and What are the labs?
Can be acquired in 20s -30s; increased risk of autoimmune disease - lymphoma - Sp infections; normal number of B cells and no plasma cells and immunoglobulin
Edema and necrosis in that region
MS - hay fever - SLE - goodpastures
T cell activation; no with CD 4 or CD 8

3. To what portion of the Antibody do the complements bind?
Th2; Th1
Defect in CD40L results in inability to class switch; a lot of IgM and no IgG - A - E
IgM or IgG antibodies coat the antigen and result in activation of MAC complex via the classical pathway OR fixed macrophages in the spleen phagoctyose the opsonized (C3b or igG) antigens - ex penicillin reaction; IgM AIHA - anti B IgMs in a group A
Fc

4. The MALT/GALT are not...
IgE
pathogenesis
encapsulated
Decreased Th1 response; disseminated mycobacterial infections; decreased interferon gamma

5. What are the autoantibodies for primary biliary cirrhosis?
IgM and IgD
active complement pathway
Anti mitochondrial
Anti TSh receptor

6. Which disease is associated with B8?
secondary
Immunoflourescent staining of tissue biopsies
Graves
IL 4 -5 -6 for B cell class switching - IL 10 to inhibit TH1

7. what else does interferon gamma do other than inducing ribonuclease production - activating NK cells - inducing increased MHC expression?
Negative!
MHC II - B7 - CD40 and CD14; CD40 and D14 for FcG and C3b resp
An alpha and beta chain; only on APCs; TCR and CD4; extracellular (phagocytosed by APCs)
Activate macrophages

8. which type of immunity is slow but long lasting? as opposed to...
Active; passive - fast but short half life (3 weeks!)
Th1; interferon gamma; IL 2 for cytotoxic T cell activation
Cell mediated due to T cell cytotoxicity reacting to foreign MHCs; few weeks after
pentamer

9. what characterizes an arthus reaction?
Edema and necrosis in that region
Negative nitroblue tetrazolium reduction test
Secretory component
1) susceptibility to encapsulated organisms 2) Howell Jolly Bodies 3) Target cells 4) Thrombocytosis

10. What part of the complement system also acts as an opsonin? What is opsonization? can you Name two other opsonins?
C3b; coating of a pathogen with molecules that promotes phagocytosis; IgG and CRP
Antidesmoglein
MHC I; from RER with help of the B2 microglobulin
Mycobacterium Tuberculosis - Mycobacterium Avium Intracellulare; Toxoplasmosis Gondii

11. IgG...
Mediates septic shock; activates the endothelium for adhesion and dilation and leukocyte recruitment results in vascular leak
T
opsonizes
Soluble C3 spontaneously hydrolyzes spontaneously to C3b and opsonizes microbial and host cell surfaces and accumulates on surfaces; C3b activates C5 convertase which leads to MAC activation

12. How do you test for type III hypersensitivity?
Th2; Th1
Immunoflourescent staining of tissue biopsies
Antiviral for uninfected cells (for future protection) and kills virally infected cells (NK activation)
IgM and IgD

13. Monomer in circulation - ___ when secreted
dimer
IL 3; supports growth and differentiation of bone marrow stem cells
Activate B cells - activate Macrophages - kill viruses directly - delayed cell mediated hypersensitivity - acute and chronic rejection
Secretory component

14. The Fc region is found on the...
S. aureus - E. Coli - aspergillus
B - T - and NK cells
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
carboxy terminal

15. Name the three opsonins
CRP - C3b - IgM
Cytokine release syndrome due to initial release from initial binding (fever etc) and hypersensitivity reaction
Capsule of lymph node is made up of type III collagen (made by reticulin fibers!) - extension of this collagen extends into the splenic tissue as trabeculae; nonspecific filtration of lymph by Macrophages - Antibody production (via activation) - stor
T cell activation; no with CD 4 or CD 8

16. What are the main cell surface proteins on B cells?
Ig - CD19 - CD20 - CD21 - CD40 - MHC II - B7
Fc
dimer
CGD; Jobs syndrome (defect in Neutrophil chemotactic response)

17. Which is the main antibody that provides passive immunity to infants?
IgG
CROSS LINK Beta region on TCR of CD4 cells to the MHC class II on APCs this results in uncoordinated release of Interferon gamma from CD4 Th1 cells and subsequent release of IL1 - IL6 and TNF alpha from Macrophages --> toxic shock syndrome; s. pyogen
An alpha and beta chain; only on APCs; TCR and CD4; extracellular (phagocytosed by APCs)
Leukocyte adhesion defect; ataxia telangietasia; ataxia telangiectasia; chediak higashi syndrome; IgA def; Digeorge syndrome; Jobs; Chediak Higashi

18. What is the pathogenesis of a candida skin test?
Delayed type hypersensitivity
Viral neutralization of igM and IgG!
CD21 on B cells (although there is T cell lymphocytosis in EBV)
Edema and necrosis in that region

19. What are the autoantibodies for pemphigus bulgaris?
C3b; coating of a pathogen with molecules that promotes phagocytosis; IgG and CRP
Basophils! THey want IG E class switch!
Antidesmoglein
Cyclosporine and tacrolimus; sirolimus (as well as hyperlipidemia)

20. What is the clinical use of Muromonab?
Immunosuppression after kidney transplantation
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
TLR ad nuclear receptors
Type IV

21. What are the labs in brutons agammaglobulinemia?
IgG and IgM bind to pathogens activating C1 convertase and leads to C2 and C4 and then C3 convertase activated
Normal pro B (CD 19 +) - no mature B cells results in decreased total B cell level - and decreased amount of immunoglobulins in each class
Rheumatic arthritis
Acts as second signal on B cells to induce class switching to IgE and IgG

22. DTH (delayed type hypersensitivity) is the ________ of a PPD reaction
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
Cytokine IL 10 secreted by Th2
First a B cell gets sensitized to an allergen - after sensitization - it gets induce by Th2 secreting IL4 to class switch from IgM to IgE - next time blood stream is exposed to allergen these antigens cross like IgEs on mast cells and result in chemi
pathogenesis

23. Which diseases are associated with DR5?
IgA; sinus and lung infections from lack of secretory defense - milk allergies and diarrhea from giardiasis; Anaphylasix on exposure to blood products with igA
acute phase reactants
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
Pernicious Anemia and Hashimotos

24. What are the three types of Type III hypersensitivity ? What is the common mechanism between them?
Immune complex - Arthus reaction and Serum sickness; they are all a result of antibody- antigen complex deposition resulting in complement activation
Cyclosporine - OKT3
lowest concentration
Previous transfusion; pregnant woman whose fetus had paternal antigens

25. How is i Th1 helper cell inhibited?
Internal iliac
Anti Jo -1
Cytokine IL 10 secreted by Th2
Cyclosporine - OKT3

26. which antibody is involved in the primary response or immediate response to an antigen?
Wiskott Aldrich syndrome
IgM
neutrophilia!
Stimulate the liver to release acute phase reactants

27. What is the defect in Brutons agammaglobulinemia? What is its effect on B cells? What is its inheritance pattern?
The place of T cell diff and maturation; ant mediastinum above heart; yes; 2
NK cells
Defect in BTK a tyrosine kinase gene; failed maturation of B cells; X linked recessive
Since it is a comp dependent type II hypersensitivity reaction; C3a brings anaphylotoxins that bring in mediators of shock

28. What happens in a secondary follicle?
Anti Jo -1
dimer
delayed!
Isotype switching (activated by Th2 cell signals and cytokines) - somatic hypermutation

29. What are HEV? Where are they found? Where does the vasculature of the lymph node travel to?
Scratch test - histamine mediated wheal; radioimmunosorbent assay (detects specific IgEs in serum)
Th2; Th1
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
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

30. The pathogenesis of contact dermatitis is ________ hypersensitivity
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
Anti alpha subunit 3 of collagen on type IV bm
type four
Septicemia with neisseria; because at least you have C3 to act like a neutrophilic chemotactic and an acute phase reactant

31. What are the autoantibodies for drug induced lupus?
Superficial inguinal
Antihistone
Steroid responsive nephrotic syndrome
IL 4 -5 -6 for B cell class switching - IL 10 to inhibit TH1

32. which cells have more complete tolerance - B or T cells?
MS
Antigliadin - antiendomysial (both are IgAs - anti tissue transgluataminase igA)
T
A - B - C; all the D's

33. Name three things that IL 1 does as a cytokine. other than the liver - who secretes IL 1
Stimulate the liver to release acute phase reactants
Chronic granulomatous disease
2 heavy chains and two light chains
Induces fever - chemokine secretion to recruit - activates adhesion molecules; macrophages

34. What are the T cell functions?
Activate B cells - activate Macrophages - kill viruses directly - delayed cell mediated hypersensitivity - acute and chronic rejection
Thrombocytopenia
Celiac
Histamine; post capillary venules - vasodilation

35. What lymph node drains the upper limb?
DM type I and RA
Th1; interferon gamma; IL 2 for cytotoxic T cell activation
Antigliadin - antiendomysial (both are IgAs - anti tissue transgluataminase igA)
Axillary

36. What does IgA pick up from epithelial cells before being secreted?
Severe recurrent pyogenic sinus and resp tract And increased susceptibility to type III hypersensitivity like SLE
Secretory component
Defect in LFA 1 integrin (CD 18) protein on phagocytes (neutrophils!); recurrent bacterial infections - severe gingivitis - poor wound healing - absent pus formation - and delayed separation of the umbilicus; neutrophilia
Activates cytotoxic CD 8 T cells as second signal

37. IgM can fix complement but...
MHC II/CD4 and B7 (on APC) and CD28 (on Th cell); releases cytokines to kill those extracellular buggers!
Humoral
Popliteal
cannot cross placenta

38. What is the autoantibody for SLE that is nonspecific? Specific?
Anti nuclear Antibodies (ANA); Anti dsDNA - anti Smith
Pernicious Anemia and Hashimotos
IgE; by activating eosinophils
An anaphylactic immediate reaction; atopy refers to the inherited propensity to develop asthmatic or allergic reactions

39. How does igA cross the epithelium?
By transcytosis
pathogenesis
dimer
Tumor cells and virally infected cells; perforin pore to secrete granzymes through it; apoptosis

40. What is the pathology in hyperacute transplant rejection?
Cytokine release syndrome due to initial release from initial binding (fever etc) and hypersensitivity reaction
Ischemia and necrosis of graft due to occlusion of vessels and fibrinoid necrosis and thrombosis within the vessels
Axillary
IgM and IgD

41. The secondary follicles have __________; primary follicles are dense
Defect in LFA 1 integrin (CD 18) protein on phagocytes (neutrophils!); recurrent bacterial infections - severe gingivitis - poor wound healing - absent pus formation - and delayed separation of the umbilicus; neutrophilia
pale central germinal centers
Para aortic
Antihistone

42. What are the autoantibodies for hashimotos?
Adenosine deaminase deficiency (AR) - defective IL 2 receptor (X linked) - and failure to synthesize MHC II; both humoral and cell mediated deficiency
...
Antimicrosomal and antithyroglobulin
Anti viral and anti tumor

43. which of the hypersensitivity reactions is not Ab mediated?
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
Type IV
T
Steroid responsive nephrotic syndrome

44. What are the PALS?
T
Lack of NADPH oxidase results in a lack of respiratory burst in neutrophils; susceptibility to catalase positive organisms (S. aureus - E. Coli - Aspergillus)
Periarteriolar lymphatic sheath in the white pulp that surround that dead end of the capillaries in the red pulp - contain T cells
TLR ad nuclear receptors

45. What is the late phase reaction of anaphylaxis allergy? what mediates it?
A chemotactic factor for neutrophils
Since it is a comp dependent type II hypersensitivity reaction; C3a brings anaphylotoxins that bring in mediators of shock
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)
Celiac

46. Give an example of someone who could get hyperacute transplant rejection.
Previous transfusion; pregnant woman whose fetus had paternal antigens
Activate macrophages
Edema and necrosis in that region
Recomb cytokine of GCSF (granulocyte macrophage colony stimulating factor; for recovery of bone marrow

47. other than eat and bite RBCs what else do Macrophages of spleen do>
IgM
Remove encapsulated bacateria
Cytokine release syndrome due to initial release from initial binding (fever etc) and hypersensitivity reaction
Paracortex; viral infection

48. What is immune complex disease? give an example.
...
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!
Yes
Type III hypersensitivity where an internal antigen antibody complexes activate classical complement pathway resulting in C3a neutrophilic chemotaxis and neutrophilic lysosomal death. SLE

49. What are the two signals required for T cells? what happens after?
When you select for which MHC it will have; take out the lymphs that self react
MHC I/CD8 and IL2/IL 2 Receptor (IL 2 is from Th1!); cytoxicity!
Activates Th1 helper cells; Macrophages
Anti Jo -1

50. What lymph node drains the lateral side of the dorsum of the foot?
Cyclosporine and tacrolimus; sirolimus (as well as hyperlipidemia)
Superficial inguinal
Popliteal
IgG