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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 is the clinical use for sirolimus? what should you combine it with?
Immunosuppression after kidney transplantation in combination with cyclosporine and corticosteroids
MS - hay fever - SLE - goodpastures
Axillary
Previous transfusion; pregnant woman whose fetus had paternal antigens

2. which antibody is involved in the primary response or immediate response to an antigen?
IgM
Recurrent infections to every type of antigen; bone marrow transplant (be weary of GVH disease!)
Stimulate the liver to release acute phase reactants
Anticentromere; anti Scl -70 (anti DNA topoisomerase I)

3. The Fc region is found on the...
Histamine (causes vasodilation) - leukotrienes (causes bronchoconstriction) - chemotaxins for eos - and heparin (increased blood flow needs to be anticoagulated!)
Anti smooth muscle
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
carboxy terminal

4. What does granzyme do? who secretes it?
Its main effect is a defect in Ab opsonization for killing
Cross link
An alpha and beta chain; only on APCs; TCR and CD4; extracellular (phagocytosed by APCs)
Its a serine protease that activates apoptosis; NK and CD8

5. What are complements in the complement system? What activates them? there seems to be different ones - What are these pathways called?
Make antibody - allergy type 1 (igE) - Cytotoxic and immunecomplex hypersensitivity type II and III (igG); hyperacute organ rejection is Ab mediated
Intracellular pathogens (acute and chronic viruses and virally induced cancers)
Proteins; IgG - IgM - endotoxin (microbial surfaces in general - nonspecific ones also) - mannose binding Lectin; classic - alternative - MB pathway (resp)
T cell precursor

6. What does CD16 on NK cells do?
Bind FcG for antibody dependent cellular cytotoxicity
IgG
An alpha chain and a B2 microglobulin; on all nucleated cells; TCR and CD8; intracellular antigens
Isotype switching (activated by Th2 cell signals and cytokines) - somatic hypermutation

7. Which disease is associated with DR7?
Yes
MHC II - B7 - CD40 and CD14; CD40 and D14 for FcG and C3b resp
Steroid responsive nephrotic syndrome
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

8. What are the symptoms of serum sickness?
Carbohydrate
Found in the red pulp; contains the cords of billroth or the splenic parenchyma that have APCs/Macrophages that closely interact with the basement membrane of the vasculature and where RBCs squeeze through into the parenchyma and interact with Macrop
Fever - urticaria - arthralgias - proteinuria - lymphadenopathy
Anti TSh receptor

9. What are the autoantibodies for hashimotos?
Both decrease cd8 tcell prolif but one through mtor and the other through calcineurin (resp)
Antimicrosomal and antithyroglobulin
By transcytosis
Found in the red pulp; contains the cords of billroth or the splenic parenchyma that have APCs/Macrophages that closely interact with the basement membrane of the vasculature and where RBCs squeeze through into the parenchyma and interact with Macrop

10. What do macrophages secrete that activate Th1 cells to secrete interferon gamma?
DM type I
TNF alpha and IL1
Histamine; post capillary venules - vasodilation
Not thymus - BM

11. What is the difference of IgE AIHA and IgG AIHA if they are both complement dependent type II hypersensitivities?
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
Since cant cross placenta most likely means that child was forced early to produce due to an infection (most likely CMV)
heavy chains
Axillary

12. what cell surface marker is used for NK cells as it is unique to them?
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
CD56
RNA segment reassortment
dimer

13. 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
Recomb cytokine of GCSF (granulocyte macrophage colony stimulating factor; for recovery of bone marrow
Influenza; antigenic shift; antigenic drift
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

14. Name two endogenous pyrogens
Interferon gamma; Th1
Rheumatic arthritis
Severe recurrent pyogenic sinus and resp tract And increased susceptibility to type III hypersensitivity like SLE
IL 1 and IL 6

15. What lymph node drains the rectum (above the pectinate line)?
Recurrent sinopulmonary bacterial infections after 6 months (d/t mothers igGs transplacental) due to opsonization defect
opsonizes
Cytokine IL 10 secreted by Th2
Internal iliac

16. Which are the only two antiinflammatory cytokines?
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
Anti SS- A (anti RO) and Anti SS- B
TGF beta and IL 10
SP infections

17. Which is the main antibody that provides passive immunity to infants?
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) susceptibility to encapsulated organisms 2) Howell Jolly Bodies 3) Target cells 4) Thrombocytosis
Barrel hoop basement membrane fenestrations
IgG

18. where do NK cells develop?
RNA segment reassortment
Anticentromere; anti Scl -70 (anti DNA topoisomerase I)
Not thymus - BM
Adaptive uses classic pathway to kill; innate uses alternative pathway to kill

19. What is the thymus ? Where is it located? is it encapsulated? How many lobes does it have?
S. aureus - E. Coli - aspergillus
Its main effect is a defect in Ab opsonization for killing
The place of T cell diff and maturation; ant mediastinum above heart; yes; 2
Antidote for digoxin intoxication

20. To what disease do the autoantibodies to IgG (rheumatoid factor)?
IgA; sinus and lung infections from lack of secretory defense - milk allergies and diarrhea from giardiasis; Anaphylasix on exposure to blood products with igA
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
Fibrosis of blood vessels and graft tissue from ischemia; obliterative vascular fibrosis with intimal thickening
Rheumatic arthritis

21. Which antibody mediates immunity to worms? how?
Paracortex; viral infection
IgE; by activating eosinophils
Hemochromatosis
Immunoflourescent staining of tissue biopsies

22. What does granulysin do?
Anti mitochondrial
Antimicrobial also secreted by CD8 and NK cells that induces apoptsosis
MHC I/CD8 and IL2/IL 2 Receptor (IL 2 is from Th1!); cytoxicity!
Cyclosporine - OKT3

23. What is the end result of complement activation? what bugs are this important for? through what pathway and why?
Anticentromere; anti Scl -70 (anti DNA topoisomerase I)
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
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
Th cells fail to produce interferon gamma; a lot of IgE

24. other than C3a - what other complement acts as an anaphyloxin?
cannot cross placenta
Viral neutralization of igM and IgG!
Superficial inguinal
C5a

25. Give an example of someone who could get hyperacute transplant rejection.
Th2; Th1
TLR ad nuclear receptors
Previous transfusion; pregnant woman whose fetus had paternal antigens
IgG

26. What is an example of a parasite showing antigenic variation?
heavy chains
Trypanosomes with programmed rearrangement (results in recurring fever -- sleeping sickness!)
Stimulate the liver to release acute phase reactants
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

27. What is the clinical use of Muromonab?
TGF beta and IL 10
Adaptive uses classic pathway to kill; innate uses alternative pathway to kill
Immunosuppression after kidney transplantation
B - T - and NK cells

28. which interleukin receptor is required for NK development? activation?
MHC I/CD8 and IL2/IL 2 Receptor (IL 2 is from Th1!); cytoxicity!
Isotype switching (activated by Th2 cell signals and cytokines) - somatic hypermutation
IL 15; IL 12 - interferon Beta and interferon alpha
TLR ad nuclear receptors

29. How do endotoxin/LPS of gram negative bacteria stimulate the immune system if they do not have a peptide fragment?
Salmonella - 2 flagellar variants; Borrelia (relapsing fever); and Neisseria gonorrhoaea - pilus protein
Secretory component
IgM and IgD
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

30. IgG...
IL 5
opsonizes
IgG
Antibody mediated cytotoxicity; either complement dependent or complement independent

31. How is i Th1 helper cell inhibited?
In the germinal center of secondary follicles (In the paler center)
IL 3; supports growth and differentiation of bone marrow stem cells
Cytokine IL 10 secreted by Th2
Antimicrobial also secreted by CD8 and NK cells that induces apoptsosis

32. What lymph node drains the lateral side of the dorsum of the foot?
MHC I/CD8 and IL2/IL 2 Receptor (IL 2 is from Th1!); cytoxicity!
Popliteal
Daclizumab; prevent ACUTE rejection of renal transplant
From self; from identical twin or clone; from nonidentical individual of same species; from different species; fetus; pig valve

33. What can cause a lymph node enlargement?
Local infection/inflammation; infection of the ln itself; metastasis
Yes
Superficial inguinal
heavy chains

34. To what portion of the Antibody do the complements bind?
Fc
Mediates septic shock; activates the endothelium for adhesion and dilation and leukocyte recruitment results in vascular leak
Negative selection
CD40 (on b cell) CD40 ligand on Th2 cell; and interleukins (4 -5 -6) from Th2 cell; CD40 is actually the second signal

35. The alternative pathway is the only constutively...
type four
Edema and necrosis in that region
active complement pathway
Internal iliac

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

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37. What are the autoantibodies for sjorgens syndrome?
Anti SS- A (anti RO) and Anti SS- B
Interferon gamma and IL 2
Influenza; antigenic shift; antigenic drift
Activates Th1 helper cells; Macrophages

38. What is the pathogenesis of chronic transplant rejection? When does it occur? is it reversible?
DM type I
Periarteriolar lymphatic sheath in the white pulp that surround that dead end of the capillaries in the red pulp - contain T cells
HBV - HBC - Kaposis - leukemias - malignant melanoma - hairy cell leukemia and condyluma accuminata
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 :(

39. T/F B cells do not require a second signal
From self; from identical twin or clone; from nonidentical individual of same species; from different species; fetus; pig valve
False! B cell class switching requires a second signal
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
Found in the red pulp; contains the cords of billroth or the splenic parenchyma that have APCs/Macrophages that closely interact with the basement membrane of the vasculature and where RBCs squeeze through into the parenchyma and interact with Macrop

40. What is the main function of IL 12? other than macrophages who else can release IL 12?
Severe pyogenic infections early in life
Induce differentiation of T cells into Th1 helper cells and activates NK cells also; B cells
neutrophilia!
Salmonella - 2 flagellar variants; Borrelia (relapsing fever); and Neisseria gonorrhoaea - pilus protein

41. What is thrombopoietin used for?
A - B - C; all the D's
Alternative splicing of mRNA
Thrombocytopenia
Carbohydrate

42. Only the _______ contribute to the Fc region
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
False! B cell class switching requires a second signal
Ischemia and necrosis of graft due to occlusion of vessels and fibrinoid necrosis and thrombosis within the vessels
heavy chains

43. How do you test for chronic granulomatous disease?
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
Surrounds the red pulp and begins with PALS and then turns into follicles with B cells/follicles
Anti smooth muscle
Negative nitroblue tetrazolium reduction test

44. Which diseases are associated with DR5?
Previous transfusion; pregnant woman whose fetus had paternal antigens
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
Cyclosporine and tacrolimus; sirolimus (as well as hyperlipidemia)
Pernicious Anemia and Hashimotos

45. What is filgrastim and sargramostim? and What is it used for?
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
Antidote for digoxin intoxication
Recomb cytokine of GCSF (granulocyte macrophage colony stimulating factor; for recovery of bone marrow
MHC I - CD16 - CD56

46. Type IV hypersensitivity is i...
MHC I; from RER with help of the B2 microglobulin
Anti SS- A (anti RO) and Anti SS- B
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
not Ab mediated

47. __________ are a part of the innate system.
By transcytosis
NK cells
Immunosuppression after kidney transplantation in combination with cyclosporine and corticosteroids
Negative!

48. Which cytokines do Th2 release and For what?
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
IL 4 -5 -6 for B cell class switching - IL 10 to inhibit TH1
The igA found in breast milk
acute phase reactants

49. Which disease is associated with DR3?
From self; from identical twin or clone; from nonidentical individual of same species; from different species; fetus; pig valve
DM type I
MS
Cells that stil have weird parts of their membrane that macrophages usually bite off

50. What are the autoantibodies for goodpastures syndrome?
Leukocyte adhesion defect; ataxia telangietasia; ataxia telangiectasia; chediak higashi syndrome; IgA def; Digeorge syndrome; Jobs; Chediak Higashi
Severe recurrent pyogenic sinus and resp tract And increased susceptibility to type III hypersensitivity like SLE
Anti alpha subunit 3 of collagen on type IV bm
Immune complex - Arthus reaction and Serum sickness; they are all a result of antibody- antigen complex deposition resulting in complement activation