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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.
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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 primary biliary cirrhosis?
Pernicious Anemia and Hashimotos
Anti mitochondrial
C5a
From self; from identical twin or clone; from nonidentical individual of same species; from different species; fetus; pig valve

2. Give an example of someone who could get hyperacute transplant rejection.
Th2; Th1
Adenosine deaminase deficiency (AR) - defective IL 2 receptor (X linked) - and failure to synthesize MHC II; both humoral and cell mediated deficiency
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
Previous transfusion; pregnant woman whose fetus had paternal antigens

3. What are the main symptoms of T cell immunodeficiencies?
1) susceptibility to encapsulated organisms 2) Howell Jolly Bodies 3) Target cells 4) Thrombocytosis
Axillary
Suppresses immune response (also specifically Th1 cells) and activates Th2; regulatory T cells
Intracellular pathogens (acute and chronic viruses and virally induced cancers)

4. What are four results of a splenectomy?
Type III hypersensitivity where an internal antigen antibody complexes activate classical complement pathway resulting in C3a neutrophilic chemotaxis and neutrophilic lysosomal death. SLE
1) susceptibility to encapsulated organisms 2) Howell Jolly Bodies 3) Target cells 4) Thrombocytosis
Lymphocytes
T cell dysfunction

5. The ______ in the BM are DN - the DP are in the cortex of thymus
Antiviral for uninfected cells (for future protection) and kills virally infected cells (NK activation)
...
IL 1 and IL 6
T cell precursor

6. What are the two signals required for B cell class switching? Which is the second signal?
TLR ad nuclear receptors
Viral neutralization of igM and IgG!
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
CD40 (on b cell) CD40 ligand on Th2 cell; and interleukins (4 -5 -6) from Th2 cell; CD40 is actually the second signal

7. What part of the lymph node specifically expands during a cellular immune response? when would this occur?
Anti smooth muscle
The patient could become cyanotic in the OR!
Anti mitochondrial
Paracortex; viral infection

8. What lymph node drains the upper limb?
Fibrosis of blood vessels and graft tissue from ischemia; obliterative vascular fibrosis with intimal thickening
Previous transfusion; pregnant woman whose fetus had paternal antigens
Normal pro B (CD 19 +) - no mature B cells results in decreased total B cell level - and decreased amount of immunoglobulins in each class
Axillary

9. Describe the Mannose Lectin pathway
Wiskott Aldrich syndrome
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
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 :(
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

10. What are the autoantibodies for goodpastures syndrome?
Ischemia and necrosis of graft due to occlusion of vessels and fibrinoid necrosis and thrombosis within the vessels
Intracellular pathogens (acute and chronic viruses and virally induced cancers)
Anti alpha subunit 3 of collagen on type IV bm
Cells that stil have weird parts of their membrane that macrophages usually bite off

11. What are the PALS?
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
Periarteriolar lymphatic sheath in the white pulp that surround that dead end of the capillaries in the red pulp - contain T cells
mesenchymal
MHC II - B7 - CD40 and CD14; CD40 and D14 for FcG and C3b resp

12. which B and T cell disorder presents with specifically low IgM?
dimer
IgM and IgG
Wiskott Aldrich syndrome
Anti smooth muscle

13. What are the cell surface proteins on NK cells?
Cross link
Fibrosis of blood vessels and graft tissue from ischemia; obliterative vascular fibrosis with intimal thickening
MS - hay fever - SLE - goodpastures
MHC I - CD16 - CD56

14. What is the clinical use of Muromonab?
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
Anticentromere; anti Scl -70 (anti DNA topoisomerase I)
IgA
Immunosuppression after kidney transplantation

15. Often bacteria are associated with being killed by humoral immunity. Name some bugs that require cell mediated immunity because they evade humoral response
Legionella - N. gonorrhea - L. monocytogenes - viruses - protozoa (leismaniasis)
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
Salmonella - 2 flagellar variants; Borrelia (relapsing fever); and Neisseria gonorrhoaea - pilus protein
Isotype switching (activated by Th2 cell signals and cytokines) - somatic hypermutation

16. Which type of selection of thymic development provides central tolerance?
Periarteriolar lymphatic sheath in the white pulp that surround that dead end of the capillaries in the red pulp - contain T cells
Complement activation (active in both)
Negative selection
Superficial inguinal

17. For which toxins are preformed antibodies (passive) given?
Anti smooth muscle
C - ANCA (antiproteinase); in neutrophil; c= cytoplasmic
Anti glutamate carboxylase and anti insulin
Tetanus - Botulinum - HBV - Rabies

18. what bacteria are a splenectomy patient most susceptible to? why?
S. aureus - E. Coli - aspergillus
Hereditary angioedema; PNH
IL 1 and IL 6
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

19. What is the common variable immunodeficiency ? How is it different from Brutons?
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
MHC II - B7 - CD40 and CD14; CD40 and D14 for FcG and C3b resp
Recom IL 11; thrombocytopenia
Antiviral for uninfected cells (for future protection) and kills virally infected cells (NK activation)

20. Which is the main antibody that provides passive immunity to infants?
Chronic granulomatous disease
IgG
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
TNF alpha and IL1

21. Only the _______ contribute to the Fc region
Graves
Antidote for digoxin intoxication
Anti mitochondrial
heavy chains

22. Name three things that IL 1 does as a cytokine. other than the liver - who secretes IL 1
Anti Jo -1
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
Induces fever - chemokine secretion to recruit - activates adhesion molecules; macrophages
Interferon gamma and IL 2

23. give an example of a virus that uses antigenic variation. What does a major variation result in? minor?
opsonizes
No because no peptide fragment!
Influenza; antigenic shift; antigenic drift
Anti glutamate carboxylase and anti insulin

24. where are complements produced?
Liver! (they are proteins circulating in the blood)
Antimicrosomal and antithyroglobulin
T
Hemochromatosis

25. What does interferon gamma do to be antiviral?
Kill them because they have CD16 on them that recognize the FcG portion
Increases expression of MHC I and MHC II and also activates NK cells
Antigliadin - antiendomysial (both are IgAs - anti tissue transgluataminase igA)
Its involved in inflammation and results in anaphylaxis and neutrophil chemotaxis.

26. The two heavy chains of an antibody contribute to the...
Alternative splicing of mRNA
Immunoflourescent staining of tissue biopsies
Fab portion
IgE; by activating eosinophils

27. What is the end result of complement activation? what bugs are this important for? through what pathway and why?
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
All MHC 1/CD8
Defect in CD40L results in inability to class switch; a lot of IgM and no IgG - A - E
Superficial inguinal

28. IgM can exist as a _______ also
Cytokine release syndrome due to initial release from initial binding (fever etc) and hypersensitivity reaction
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
pentamer
Leukocyte adhesion defect; ataxia telangietasia; ataxia telangiectasia; chediak higashi syndrome; IgA def; Digeorge syndrome; Jobs; Chediak Higashi

29. IgE has the ___________ in the serum
Activates Th1 helper cells; Macrophages
lowest concentration
Activates cytotoxic CD 8 T cells as second signal
cannot cross placenta

30. What is the defect in Brutons agammaglobulinemia? What is its effect on B cells? What is its inheritance pattern?
Cytokine IL 10 secreted by Th2
Thrombocytopenia
Local infection/inflammation; infection of the ln itself; metastasis
Defect in BTK a tyrosine kinase gene; failed maturation of B cells; X linked recessive

31. What happens in a deficiency of C3?
Leukocyte adhesion defect; ataxia telangietasia; ataxia telangiectasia; chediak higashi syndrome; IgA def; Digeorge syndrome; Jobs; Chediak Higashi
No because no peptide fragment!
Severe recurrent pyogenic sinus and resp tract And increased susceptibility to type III hypersensitivity like SLE
Activates Macrophages and Th1 cells; suppresses Th2 cells; antiviral and antitumor

32. What is digoxin immune Fab used for?
2 heavy chains and two light chains
Bind FcG for antibody dependent cellular cytotoxicity
Antidote for digoxin intoxication
MHC II - B7 - CD40 and CD14; CD40 and D14 for FcG and C3b resp

33. What type of cells do NK cells attack? with What tools? by necrosis or apoptosis?
Vasculitis of graft vessels with dense interstitial lymphocytic infiltrate; yes! with immunosuppressants
Tumor cells and virally infected cells; perforin pore to secrete granzymes through it; apoptosis
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
IgA; sinus and lung infections from lack of secretory defense - milk allergies and diarrhea from giardiasis; Anaphylasix on exposure to blood products with igA

34. How does igA cross the epithelium?
cannot cross placenta
Antimicrobial also secreted by CD8 and NK cells that induces apoptsosis
By transcytosis
Salmonella - 2 flagellar variants; Borrelia (relapsing fever); and Neisseria gonorrhoaea - pilus protein

35. What are the autoantibodies for drug induced lupus?
Antihistone
Isotype switching (activated by Th2 cell signals and cytokines) - somatic hypermutation
type four
Adaptive uses classic pathway to kill; innate uses alternative pathway to kill

36. What is the mechanism for sirolimus? what else it known as?
Anemias (esp due to renal failure)
Binds to Mtor which (like tacrolimus and cyclosporine just in a different pathway) inhibits IL 2 production and thus t cell proliferation in response to IL 2 producton
Stimulate the liver to release acute phase reactants
Chronic granulomatous disease

37. The pathogenesis of contact dermatitis is ________ hypersensitivity
False! B cell class switching requires a second signal
type four
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
Antihistone

38. hat is the presentation of Jobs syndrome or Hyper IgE?
Coarse Faces - cold (noninflamed d/t inability to attract neutrophils) staph abscesses - retained primary teeth - high igE - dermatologic problems (eczema)
Antigliadin - antiendomysial (both are IgAs - anti tissue transgluataminase igA)
Recurrent infections to every type of antigen; bone marrow transplant (be weary of GVH disease!)
Carbohydrate

39. Which is the most abundant antibody in blood?
Since cant cross placenta most likely means that child was forced early to produce due to an infection (most likely CMV)
IgG
Alternative splicing of mRNA
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

40. What lymph node drains the stomach?
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
neutrophilia!
Celiac
IgG

41. The MALT/GALT are not...
Normal pro B (CD 19 +) - no mature B cells results in decreased total B cell level - and decreased amount of immunoglobulins in each class
Local infection/inflammation; infection of the ln itself; metastasis
encapsulated
IL 4 - 5 - 10 - 6

42. What are the cell surface proteins for Macrophages? which two are for opsonins?
An alpha chain and a B2 microglobulin; on all nucleated cells; TCR and CD8; intracellular antigens
MHC II - B7 - CD40 and CD14; CD40 and D14 for FcG and C3b resp
Previous transfusion; pregnant woman whose fetus had paternal antigens
DAF and C1 esterase inhibitor on cells prevent complement activation on their surfaces (microbial surfaces lack this)

43. How do you test for type III hypersensitivity?
Antihistone
Immunoflourescent staining of tissue biopsies
Anti topoisomerase
Previous transfusion; pregnant woman whose fetus had paternal antigens

44. The lymphocytes are ________ origin
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
mesenchymal
Activates Th1 helper cells; Macrophages
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

45. Which are the only two antiinflammatory cytokines?
active complement pathway
Th cells fail to produce interferon gamma; a lot of IgE
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 :(
TGF beta and IL 10

46. What is the main function of interferons?
Cytokine release syndrome due to initial release from initial binding (fever etc) and hypersensitivity reaction
Antiviral for uninfected cells (for future protection) and kills virally infected cells (NK activation)
Fever - urticaria - arthralgias - proteinuria - lymphadenopathy
Intracellular pathogens (acute and chronic viruses and virally induced cancers)

47. How do endotoxin/LPS of gram negative bacteria stimulate the immune system if they do not have a peptide fragment?
...
1) susceptibility to encapsulated organisms 2) Howell Jolly Bodies 3) Target cells 4) Thrombocytosis
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
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

48. What does granzyme do? who secretes it?
Its a serine protease that activates apoptosis; NK and CD8
Carbohydrate
Antidote for digoxin intoxication
Barrel hoop basement membrane fenestrations

49. Which disease is associated with B8?
cannot cross placenta
not Ab mediated
Type III hypersensitivity where an internal antigen antibody complexes activate classical complement pathway resulting in C3a neutrophilic chemotaxis and neutrophilic lysosomal death. SLE
Graves

50. 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?
Leukocyte adhesion defect; ataxia telangietasia; ataxia telangiectasia; chediak higashi syndrome; IgA def; Digeorge syndrome; Jobs; Chediak Higashi
Cyclosporine - OKT3
An antigen encounter (presented by APC for Th2) with Th2 will result in it to go to the cortical section and help with B cell activation; Cytotoxic T cell will enter vasculature/efferent lymph to go kill; B cell will wait for Th2 for activation and t
IgG