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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 is Aldesleukin? What is it used for
Negative!
A recomb cytokine of IL 2; RCC and metastatic melanoma
Axillary
Antigliadin - antiendomysial (both are IgAs - anti tissue transgluataminase igA)

2. What is the pathology seen in chronic transplant rejection?
MHC I; from RER with help of the B2 microglobulin
Fibrosis of blood vessels and graft tissue from ischemia; obliterative vascular fibrosis with intimal thickening
IgA
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

3. What is MHC I made out of? Where is it found? What does it bind to? What type of antigens does it present?
Psoriasis - Ankylosis Spondylitis - IBD - Reiters; all seronegative spondylopathies
Fc
Internal iliac
An alpha chain and a B2 microglobulin; on all nucleated cells; TCR and CD8; intracellular antigens

4. What is ataxia telangectasia? What is it caused by? What is the triad of presentation? and its labs?
Anti TSh receptor
A B and T cell disorder; defect in DNA repair enzymes; ataxia - telangactasia and IgA def; igA def. and increased AFP
Glycoproteins; HLA
Isotype switching (activated by Th2 cell signals and cytokines) - somatic hypermutation

5. What is recomb beta interferon used for?
Cross link
MS
Th2; Th1
IgM and IgD

6. IgM can fix complement but...
Hyperacute; presence of preformed antibodies in the recipient ( to blood groups or HLA )
cannot cross placenta
T cell activation; no with CD 4 or CD 8
CGD; Jobs syndrome (defect in Neutrophil chemotactic response)

7. Type IV hypersensitivity is i...
Local infection/inflammation; infection of the ln itself; metastasis
not Ab mediated
isotype
Yes

8. what cell surface proteins are on all APCs?
DM type I and RA
Salmonella - 2 flagellar variants; Borrelia (relapsing fever); and Neisseria gonorrhoaea - pilus protein
MHC II - B7
IL 1 - IL 6 - IL 12 - TNF alpha; IL 6- Th2 cells; IL 12- B cells

9. How fast does it occur?
Superficial inguinal
Its involved in inflammation and results in anaphylaxis and neutrophil chemotaxis.
Lymphocytes
The patient could become cyanotic in the OR!

10. Which helper T cells' development is induced by IL 4? IL 12?
MHC I - CD16 - CD56
Antimicrobial also secreted by CD8 and NK cells that induces apoptsosis
Th2; Th1
C - ANCA (antiproteinase); in neutrophil; c= cytoplasmic

11. other than eat and bite RBCs what else do Macrophages of spleen do>
Anti TSh receptor
Remove encapsulated bacateria
Thrombocytopenia
IL 1 and IL 6

12. Which antibodies can be multimeric?
Interferon gamma and IL 2
A recomb cytokine of IL 2; RCC and metastatic melanoma
IgM and IgA
Axillary

13. What lymph node drains the upper limb?
A chemotactic factor for neutrophils
Anemias (esp due to renal failure)
not Ab mediated
Axillary

14. what will NK cells do to cells covered in IgG Ab? why?
Kill them because they have CD16 on them that recognize the FcG portion
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
Mediates septic shock; activates the endothelium for adhesion and dilation and leukocyte recruitment results in vascular leak
...

15. If an antigen lacks a peptide component How does the adaptive immunity attack it? What type of response is this called. give an example of bugs that do this. what implications does this have on splenectomy?
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
This means that MHC can not recognize it and thus will not be phagocytosed. The humoral response rescues - IgM is the primary response attack. Since there is no class switching (without MHC activation no CD40 L and interleukins to activate!) then the
Anti SS- A (anti RO) and Anti SS- B
Negative selection

16. What is the clinical use for sirolimus? what should you combine it with?
Immunosuppression after kidney transplantation in combination with cyclosporine and corticosteroids
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
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
Anti IF

17. Monomer in circulation - ___ when secreted
Anti SS- A (anti RO) and Anti SS- B
dimer
Kill them because they have CD16 on them that recognize the FcG portion
Negative selection

18. What is colostrum?
The igA found in breast milk
Bind FcG for antibody dependent cellular cytotoxicity
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
Sinusitis - otitis media - pneumonia

19. Name the three opsonins
isotype
CRP - C3b - IgM
IgM and IgD
Viral neutralization of igM and IgG!

20. What are the autoantibodies for goodpastures syndrome?
Anti glutamate carboxylase and anti insulin
Immunosuppression after kidney transplantation
Antigliadin - antiendomysial (both are IgAs - anti tissue transgluataminase igA)
Anti alpha subunit 3 of collagen on type IV bm

21. The lymphocytes are ________ origin
IgM
Leukocyte adhesion defect; ataxia telangietasia; ataxia telangiectasia; chediak higashi syndrome; IgA def; Digeorge syndrome; Jobs; Chediak Higashi
mesenchymal
Celiac

22. What is the pathogenesis of HyperIgE syndrome? What are the labs?
Cytokine IL 10 secreted by Th2
isotype
Anti alpha subunit 3 of collagen on type IV bm
Th cells fail to produce interferon gamma; a lot of IgE

23. What is the white pulp of the spleen?
Induce differentiation of T cells into Th1 helper cells and activates NK cells also; B cells
Immune complex - Arthus reaction and Serum sickness; they are all a result of antibody- antigen complex deposition resulting in complement activation
T
Surrounds the red pulp and begins with PALS and then turns into follicles with B cells/follicles

24. What is hereditary angioedema? What are the C3 levels?
Normal pro B (CD 19 +) - no mature B cells results in decreased total B cell level - and decreased amount of immunoglobulins in each class
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
A B and T cell disorder; defect in DNA repair enzymes; ataxia - telangactasia and IgA def; igA def. and increased AFP
MHC II - B7

25. The Fc region is found on the...
Antidesmoglein
MHC I; from RER with help of the B2 microglobulin
carboxy terminal
Stimulate the liver to release acute phase reactants

26. T/F B cells do not require a second signal
False! B cell class switching requires a second signal
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 :(
Increases expression of MHC I and MHC II and also activates NK cells
Lymphocytes

27. What does interferon gamma do? What two type of cells does it attack mostly?
IL 4 - 5 - 10 - 6
Complement activation (active in both)
Activates Macrophages and Th1 cells; suppresses Th2 cells; antiviral and antitumor
Humoral

28. What is the pathogenesis of acute transplant rejection? When does it occur?
Negative!
Recurrent sinopulmonary bacterial infections after 6 months (d/t mothers igGs transplacental) due to opsonization defect
IgE
Cell mediated due to T cell cytotoxicity reacting to foreign MHCs; few weeks after

29. What is an autograft? syngeneic graft? allograft? xenograft? What is an ex of an allograft? xenograft?
Anti Jo -1
From self; from identical twin or clone; from nonidentical individual of same species; from different species; fetus; pig valve
Glycoproteins; HLA
SP infections

30. From where do cytokines come from?
NK cells
Recom IL 11; thrombocytopenia
Lymphocytes
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

31. can igG cross the placenta?
Steroid responsive nephrotic syndrome
Yes
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!
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)

32. What are the cell surface proteins for Macrophages? which two are for opsonins?
MHC II - B7 - CD40 and CD14; CD40 and D14 for FcG and C3b resp
Influenza; antigenic shift; antigenic drift
Viral neutralization of igM and IgG!
Edema and necrosis in that region

33. What part of the lymph node specifically expands during a cellular immune response? when would this occur?
Paracortex; viral infection
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
Edema and necrosis in that region
not Ab mediated

34. What is the pathogenesis of a candida skin test?
Delayed type hypersensitivity
T cell activation; no with CD 4 or CD 8
Cross link antigens which increases their phagocytability; activate complement for MAC attack; opsonization; neutralization
IL 1 and IL 6

35. What do mature naive B lymphocytes express?
IgM and IgD
Acts as second signal on B cells to induce class switching to IgE and IgG
C - ANCA (antiproteinase); in neutrophil; c= cytoplasmic
Local infection/inflammation; infection of the ln itself; metastasis

36. What are C1 - C2 - C3 - C4 important for?
Opsonize bacteria (for enhanced phagocytosis) - neutralize viruses (igG) - activate complement (igM and igG) - sensitize mast cells (igE)
Adenosine deaminase deficiency (AR) - defective IL 2 receptor (X linked) - and failure to synthesize MHC II; both humoral and cell mediated deficiency
Viral neutralization of igM and IgG!
Salmonella - 2 flagellar variants; Borrelia (relapsing fever); and Neisseria gonorrhoaea - pilus protein

37. What is chronic mucocutaneous candidiasis d/t?
Anti Jo -1
Influenza; antigenic shift; antigenic drift
T cell dysfunction
Periarteriolar lymphatic sheath in the white pulp that surround that dead end of the capillaries in the red pulp - contain T cells

38. 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
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
Recurrent infections to every type of antigen; bone marrow transplant (be weary of GVH disease!)
HBV - HBC - Kaposis - leukemias - malignant melanoma - hairy cell leukemia and condyluma accuminata

39. What lymph node drains the scrotum?
Its a serine protease that activates apoptosis; NK and CD8
Anticentromere; anti Scl -70 (anti DNA topoisomerase I)
Superficial inguinal
Anemias (esp due to renal failure)

40. 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
Not thymus - BM
P - ANCA (antimyeloperoxidase); in neutrophil; p= perinuclear

41. What is the main function of interferons?
Antiviral for uninfected cells (for future protection) and kills virally infected cells (NK activation)
False! B cell class switching requires a second signal
Axillary
Daclizumab; prevent ACUTE rejection of renal transplant

42. What does it mean if there are igM in the serum at birth?
An anaphylactic immediate reaction; atopy refers to the inherited propensity to develop asthmatic or allergic reactions
pathogenesis
Since cant cross placenta most likely means that child was forced early to produce due to an infection (most likely CMV)
DM type I and RA

43. What are the three immune privileged sites? why are they called that? what happens after infection in these areas?
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
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
Recurrent infections to every type of antigen; bone marrow transplant (be weary of GVH disease!)
Yes

44. What cytokines to Th2 secrete?
IL 4 - 5 - 10 - 6
Recomb cytokine of GCSF (granulocyte macrophage colony stimulating factor; for recovery of bone marrow
Anti Ach receptor
DAF and C1 esterase inhibitor on cells prevent complement activation on their surfaces (microbial surfaces lack this)

45. What is the symptoms involved in graft versus host disease? it What transplant cases does it usually occur? give an example
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
MHC class molecules bind to KIRS or CD94 to prevent killing
...
Complement activation (active in both)

46. 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
Remove encapsulated bacateria
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
Kill them because they have CD16 on them that recognize the FcG portion

47. What are the two signals to kill for NK cells?
Anticentromere; anti Scl -70 (anti DNA topoisomerase I)
IgE
Lack of MHC class I constant region which it binds or a nonspecific activation signal (TLR)
Paracortex; viral infection

48. What is MHC II made out of? Where is it found? What does it bind to? What type of antigens does it present?
delayed!
An alpha and beta chain; only on APCs; TCR and CD4; extracellular (phagocytosed by APCs)
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
Anti viral and anti tumor

49. Which is the main antibody in the delayed or secondary response to an antigen?
Anti smooth muscle
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
IgG
TCR - CD4/8 - CD28 (binds B7) - CD3 (for intracellular transduction) - CD40L

50. Which Thelper cell activated Macrophages? by secreting what? what else does Th1 secrete? For what?
Recurrent sinopulmonary bacterial infections after 6 months (d/t mothers igGs transplacental) due to opsonization defect
Negative nitroblue tetrazolium reduction test
opsonizes
Th1; interferon gamma; IL 2 for cytotoxic T cell activation