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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 myasthenia gravis?
Anti Ach receptor
An anaphylactic immediate reaction; atopy refers to the inherited propensity to develop asthmatic or allergic reactions
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
MHC I; from RER with help of the B2 microglobulin

2. Name 5 ways Antibody diversity is generated?
Anti Ach receptor
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
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
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

3. Which diseases are associated with DR5?
Wiskott Aldrich syndrome
Pernicious Anemia and Hashimotos
T cells react to the angtigen and activate leukocyted (macrophage acitivation)
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

4. Which type of selection of thymic development provides central tolerance?
Negative selection
not Ab mediated
CD40 (on b cell) CD40 ligand on Th2 cell; and interleukins (4 -5 -6) from Th2 cell; CD40 is actually the second signal
Cross link

5. What links the adaptive and innate immunity?
Complement activation (active in both)
pale central germinal centers
IgE; by activating eosinophils
Lymphocytes

6. The MALT/GALT are not...
Kill them because they have CD16 on them that recognize the FcG portion
Rheumatic arthritis
cannot cross placenta
encapsulated

7. other than eat and bite RBCs what else do Macrophages of spleen do>
Axillary
IL 3; supports growth and differentiation of bone marrow stem cells
Remove encapsulated bacateria
TGF beta and IL 10

8. What is the defect in Leukocyte adhesion defect? What is the presentation? What are the labs?
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
Ig - CD19 - CD20 - CD21 - CD40 - MHC II - B7
Axillary
Th1; interferon gamma; IL 2 for cytotoxic T cell activation

9. when can graft versus host disease? What is the result?
MS - hay fever - SLE - goodpastures
Antimicrobial also secreted by CD8 and NK cells that induces apoptsosis
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
Histamine (causes vasodilation) - leukotrienes (causes bronchoconstriction) - chemotaxins for eos - and heparin (increased blood flow needs to be anticoagulated!)

10. What are the autoantibodies for wegeners granulomatosis?
Trypanosomes with programmed rearrangement (results in recurring fever -- sleeping sickness!)
C - ANCA (antiproteinase); in neutrophil; c= cytoplasmic
MS
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

11. Which cytokines do Th2 release and For what?
IL 4 -5 -6 for B cell class switching - IL 10 to inhibit TH1
Antimicrosomal and antithyroglobulin
Cells that stil have weird parts of their membrane that macrophages usually bite off
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

12. What is a type I hypersensitivity reaction? What is atopic?
In the germinal center of secondary follicles (In the paler center)
An anaphylactic immediate reaction; atopy refers to the inherited propensity to develop asthmatic or allergic reactions
carboxy terminal
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

13. What bugs can actually infect the lymph node itself?
MHC II - B7 - CD40 and CD14; CD40 and D14 for FcG and C3b resp
Mycobacterium Tuberculosis - Mycobacterium Avium Intracellulare; Toxoplasmosis Gondii
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
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

14. Which TCR MHC system is important for viral immunity? neoplastic? donor graft cells?
Leukocyte adhesion defect; ataxia telangietasia; ataxia telangiectasia; chediak higashi syndrome; IgA def; Digeorge syndrome; Jobs; Chediak Higashi
Psoriasis - Ankylosis Spondylitis - IBD - Reiters; all seronegative spondylopathies
MHC II - B7
All MHC 1/CD8

15. What is recomb beta interferon used for?
carboxy terminal
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
A chemotactic factor for neutrophils
MS

16. is IgM an opsonizer?
IL 3; supports growth and differentiation of bone marrow stem cells
Negative!
The place of T cell diff and maturation; ant mediastinum above heart; yes; 2
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

17. What kinds of receptors activate innate immunity?
IgG and IgM bind to pathogens activating C1 convertase and leads to C2 and C4 and then C3 convertase activated
dimer
TLR ad nuclear receptors
Previous transfusion; pregnant woman whose fetus had paternal antigens

18. __________ are a part of the innate system.
False! B cell class switching requires a second signal
Cytokine release syndrome due to initial release from initial binding (fever etc) and hypersensitivity reaction
NK cells
...

19. What are C1 - C2 - C3 - C4 important for?
Popliteal
Viral neutralization of igM and IgG!
Fibrosis of blood vessels and graft tissue from ischemia; obliterative vascular fibrosis with intimal thickening
mesenchymal

20. What are the autoantibodies for polymyositis and dermatomyositis?
pathogenesis
Cytokine release syndrome due to initial release from initial binding (fever etc) and hypersensitivity reaction
Anti Jo -1
Its a serine protease that activates apoptosis; NK and CD8

21. What does IgA pick up from epithelial cells before being secreted?
Macrophages - Dendritic cells - B cells
Mediates septic shock; activates the endothelium for adhesion and dilation and leukocyte recruitment results in vascular leak
Secretory component
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

22. What are the two signals required for B cell class switching? Which is the second signal?
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
IgM
IL 4
CD40 (on b cell) CD40 ligand on Th2 cell; and interleukins (4 -5 -6) from Th2 cell; CD40 is actually the second signal

23. what else does interferon gamma do other than inducing ribonuclease production - activating NK cells - inducing increased MHC expression?
Activate macrophages
isotype
T cell precursor
Activates Macrophages and Th1 cells; suppresses Th2 cells; antiviral and antitumor

24. What are the mediators that mast cells release?
Histamine (causes vasodilation) - leukotrienes (causes bronchoconstriction) - chemotaxins for eos - and heparin (increased blood flow needs to be anticoagulated!)
Since it is a comp dependent type II hypersensitivity reaction; C3a brings anaphylotoxins that bring in mediators of shock
Negative selection
Remove encapsulated bacateria

25. What lymph node drains the anal canal (below the pectinate line)?
Superficial inguinal
pathogenesis
IgA
Monoclonal Ab to CD3- blocks cellular transduction and signaling of T cells

26. Describe the Mannose Lectin pathway
IgA; sinus and lung infections from lack of secretory defense - milk allergies and diarrhea from giardiasis; Anaphylasix on exposure to blood products with igA
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
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
IL 1 - IL 6 - IL 12 - TNF alpha; IL 6- Th2 cells; IL 12- B cells

27. What lymph node drains the stomach?
Complement activation (active in both)
Cytokine IL 10 secreted by Th2
Cytokine release syndrome due to initial release from initial binding (fever etc) and hypersensitivity reaction
Celiac

28. Which disease is associated with HLA A3?
Ig - CD19 - CD20 - CD21 - CD40 - MHC II - B7
Salmonella - 2 flagellar variants; Borrelia (relapsing fever); and Neisseria gonorrhoaea - pilus protein
Hemochromatosis
Its a serine protease that activates apoptosis; NK and CD8

29. IgM can fix complement but...
Delayed type hypersensitivity
Lack of response from lymphocytes when activated; because they are self reactive - this is a form of tolerance
Leukocyte adhesion defect; ataxia telangietasia; ataxia telangiectasia; chediak higashi syndrome; IgA def; Digeorge syndrome; Jobs; Chediak Higashi
cannot cross placenta

30. What does it mean if there are igM in the serum at birth?
Cyclosporine - OKT3
Anti glutamate carboxylase and anti insulin
Since cant cross placenta most likely means that child was forced early to produce due to an infection (most likely CMV)
Anemias (esp due to renal failure)

31. What does IL 10 do? who is secreted by?
Lymphocytes
Paracortex
Cell mediated due to T cell cytotoxicity reacting to foreign MHCs; few weeks after
Suppresses immune response (also specifically Th1 cells) and activates Th2; regulatory T cells

32. What is the toxicity of azathioprine?
...
Tumor cells and virally infected cells; perforin pore to secrete granzymes through it; apoptosis
Not thymus - BM
Paracortex; viral infection

33. What lymph node drains the thigh?
Superficial inguinal
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
Local infection/inflammation; infection of the ln itself; metastasis
Histamine (causes vasodilation) - leukotrienes (causes bronchoconstriction) - chemotaxins for eos - and heparin (increased blood flow needs to be anticoagulated!)

34. What is the presentation of Brutons agammaglobulinemia?
Recurrent sinopulmonary bacterial infections after 6 months (d/t mothers igGs transplacental) due to opsonization defect
Activates cytotoxic CD 8 T cells as second signal
DAF and C1 esterase inhibitor on cells prevent complement activation on their surfaces (microbial surfaces lack this)
A j chain

35. Which is the most abundant antibody in blood?
Not thymus - BM
IgG
isotype
Immunoflourescent staining of tissue biopsies

36. what ensure that a memory response is generated?
MHC class molecules bind to KIRS or CD94 to prevent killing
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
Kill them because they have CD16 on them that recognize the FcG portion
If there is class switching and plasma cell production (that is when memory cells are produced)

37. What is digoxin immune Fab 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
Internal iliac
Antidote for digoxin intoxication
Lack of response from lymphocytes when activated; because they are self reactive - this is a form of tolerance

38. What are the autoantibodies for systemic sclerosis?
IL 4 -5 -6 for B cell class switching - IL 10 to inhibit TH1
Adaptive uses classic pathway to kill; innate uses alternative pathway to kill
The patient could become cyanotic in the OR!
Anti topoisomerase

39. What is the main cytokine released by T cells? What does it do
Anti mitochondrial
IL 3; supports growth and differentiation of bone marrow stem cells
Opsonize bacteria (for enhanced phagocytosis) - neutralize viruses (igG) - activate complement (igM and igG) - sensitize mast cells (igE)
Hemochromatosis

40. What are the autoantibodies for hashimotos?
Make antibody - allergy type 1 (igE) - Cytotoxic and immunecomplex hypersensitivity type II and III (igG); hyperacute organ rejection is Ab mediated
Anti Ach receptor
Antimicrosomal and antithyroglobulin
TNF alpha and IL1

41. What are the symptoms of serum sickness?
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
Graves
MHC I/CD8 and IL2/IL 2 Receptor (IL 2 is from Th1!); cytoxicity!
Fever - urticaria - arthralgias - proteinuria - lymphadenopathy

42. What is the difference of IgE AIHA and IgG AIHA if they are both complement dependent type II hypersensitivities?
Para aortic
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
heavy chains
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

43. What are the autoantibodies for drug induced lupus?
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
Antihistone
Its involved in inflammation and results in anaphylaxis and neutrophil chemotaxis.
Humoral

44. In general What are T cells good for?
Activates Macrophages and Th1 cells; suppresses Th2 cells; antiviral and antitumor
Ig - CD19 - CD20 - CD21 - CD40 - MHC II - B7
An anaphylactic immediate reaction; atopy refers to the inherited propensity to develop asthmatic or allergic reactions
Anti viral and anti tumor

45. What is the antimetabolite precursor of 6 mercaptopurine? What is the result?
...
Surrounds the red pulp and begins with PALS and then turns into follicles with B cells/follicles
CGD; Jobs syndrome (defect in Neutrophil chemotactic response)
From self; from identical twin or clone; from nonidentical individual of same species; from different species; fetus; pig valve

46. What is the pathogenesis of IgG AIHA ABO hemolytic disease of a newborn? describe what happens.
IL 3; supports growth and differentiation of bone marrow stem cells
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
MHC II/CD4 and B7 (on APC) and CD28 (on Th cell); releases cytokines to kill those extracellular buggers!
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

47. Name the three opsonins
CRP - C3b - IgM
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
Leukocyte adhesion defect; ataxia telangietasia; ataxia telangiectasia; chediak higashi syndrome; IgA def; Digeorge syndrome; Jobs; Chediak Higashi
Coarse Faces - cold (noninflamed d/t inability to attract neutrophils) staph abscesses - retained primary teeth - high igE - dermatologic problems (eczema)

48. The ______ in the BM are DN - the DP are in the cortex of thymus
CRP - C3b - IgM
Acts as second signal on B cells to induce class switching to IgE and IgG
Influenza; antigenic shift; antigenic drift
T cell precursor

49. Type IV hypersensitivity is i...
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)
not Ab mediated
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
HBV - HBC - Kaposis - leukemias - malignant melanoma - hairy cell leukemia and condyluma accuminata

50. From where do cytokines come from?
Septicemia with neisseria; because at least you have C3 to act like a neutrophilic chemotactic and an acute phase reactant
The patient could become cyanotic in the OR!
Lymphocytes
Sinusitis - otitis media - pneumonia