Test your basic knowledge |

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. describe the pathogenesis of delayed type IV hypersensitivity
IgM and IgD
Defect in BTK a tyrosine kinase gene; failed maturation of B cells; X linked recessive
T cells react to the angtigen and activate leukocyted (macrophage acitivation)
Immune complex - Arthus reaction and Serum sickness; they are all a result of antibody- antigen complex deposition resulting in complement activation

2. Describe the interstitial tissue of a spleen including the sinuses. What type of cells are found in the four structures (cortex - paracortex - medulla and sinuses)?
The interstitial tissue of a lymph node is structured into the cortex on the outside Which is densely cellular which transitions into the paracortex Which is less dense and then the medulla Which is least dense. The cells that inhabit these tissues a
Nuclear remnants that are usually taken out of RBC before complete maturation by Macrophages
Interferon gamma and IL 2
1) susceptibility to encapsulated organisms 2) Howell Jolly Bodies 3) Target cells 4) Thrombocytosis

3. Type Iv hypersensitivity is...
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
delayed!
Anti Jo -1
Anti viral and anti tumor

4. Which disease is associated with DR3?
DM type I
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
acute phase reactants
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

5. What does IL 4 do?
Antigliadin - antiendomysial (both are IgAs - anti tissue transgluataminase igA)
Acts as second signal on B cells to induce class switching to IgE and IgG
Increases expression of MHC I and MHC II and also activates NK cells
T cell precursor

6. What are the autoantibodies for myasthenia gravis?
Anti Ach receptor
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
Vasculitis of graft vessels with dense interstitial lymphocytic infiltrate; yes! with immunosuppressants
Since it is a comp dependent type II hypersensitivity reaction; C3a brings anaphylotoxins that bring in mediators of shock

7. What is the white pulp of the spleen?
Anti Jo -1
Inferior mesenteric
IgAs in mothers breast milk!
Surrounds the red pulp and begins with PALS and then turns into follicles with B cells/follicles

8. What part of the lymph node specifically expands during a cellular immune response? when would this occur?
Cytokine IL 10 secreted by Th2
Paracortex; viral infection
Axillary
A B and T cell disorder; defect in DNA repair enzymes; ataxia - telangactasia and IgA def; igA def. and increased AFP

9. What is passive immunity?
Lymphocytes
IL 1 - IL 6 - IL 12 - TNF alpha; IL 6- Th2 cells; IL 12- B cells
Receiving preformed Antibodies
Adenosine deaminase deficiency (AR) - defective IL 2 receptor (X linked) - and failure to synthesize MHC II; both humoral and cell mediated deficiency

10. The MALT/GALT are not...
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
Defect in CD40L results in inability to class switch; a lot of IgM and no IgG - A - E
encapsulated
An alpha chain and a B2 microglobulin; on all nucleated cells; TCR and CD8; intracellular antigens

11. What lymph node drains the upper limb?
Axillary
Viral neutralization of igM and IgG!
IL 4
IgM and IgA

12. What are the three types of Type III hypersensitivity ? What is the common mechanism between them?
T cell dysfunction
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
CD40 (on b cell) CD40 ligand on Th2 cell; and interleukins (4 -5 -6) from Th2 cell; CD40 is actually the second signal
Immune complex - Arthus reaction and Serum sickness; they are all a result of antibody- antigen complex deposition resulting in complement activation

13. What is the presentation of hyperIgM syndrome?
IL 4 -5 -6 for B cell class switching - IL 10 to inhibit TH1
HBV - HBC - Kaposis - leukemias - malignant melanoma - hairy cell leukemia and condyluma accuminata
Acts as second signal on B cells to induce class switching to IgE and IgG
Severe pyogenic infections early in life

14. What lymph node drains the scrotum?
A recomb cytokine of IL 2; RCC and metastatic melanoma
Superficial inguinal
The interstitial tissue of a lymph node is structured into the cortex on the outside Which is densely cellular which transitions into the paracortex Which is less dense and then the medulla Which is least dense. The cells that inhabit these tissues a
A chemotactic factor for neutrophils

15. What are the main cell surface proteins on B cells?
Axillary
Ig - CD19 - CD20 - CD21 - CD40 - MHC II - B7
not Ab mediated
Anti SS- A (anti RO) and Anti SS- B

16. Which disease is associated withB B27?
Cross link
Psoriasis - Ankylosis Spondylitis - IBD - Reiters; all seronegative spondylopathies
An alpha chain and a B2 microglobulin; on all nucleated cells; TCR and CD8; intracellular antigens
Anti TSh receptor

17. How do you test for chronic granulomatous disease?
Negative nitroblue tetrazolium reduction test
isotype
Anti TSh receptor
Yes

18. which antibodies prevent antigens from binding mucosal surfaces?
Vasculitis of graft vessels with dense interstitial lymphocytic infiltrate; yes! with immunosuppressants
IgA
neutrophilia!
...

19. Which helper T cells' development is induced by IL 4? IL 12?
Lack of NADPH oxidase results in a lack of respiratory burst in neutrophils; susceptibility to catalase positive organisms (S. aureus - E. Coli - Aspergillus)
Th2; Th1
pathogenesis
Fc

20. where do NK cells develop?
Fab portion
T cell precursor
isotype
Not thymus - BM

21. What is oprelevkin? and What is it used for?
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
Recom IL 11; thrombocytopenia
By transcytosis
Lack of response from lymphocytes when activated; because they are self reactive - this is a form of tolerance

22. What is three common causes of severe combined immunodef? What is the result of all three?
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!
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
Adenosine deaminase deficiency (AR) - defective IL 2 receptor (X linked) - and failure to synthesize MHC II; both humoral and cell mediated deficiency
Septicemia with neisseria; because at least you have C3 to act like a neutrophilic chemotactic and an acute phase reactant

23. What is the arthus reaction? What is the difference between arthus and serum sickness? give an example. How do you test for it?
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
...
T cells react to the angtigen and activate leukocyted (macrophage acitivation)
Yes

24. The two heavy chains of an antibody contribute to the...
A chemotactic factor for neutrophils
Fab portion
dimer
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

25. Other than stimulating fever - what else does IL 6 do?
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
Stimulate the liver to release acute phase reactants
Decreased Th1 response; disseminated mycobacterial infections; decreased interferon gamma
Th1; interferon gamma; IL 2 for cytotoxic T cell activation

26. What lymph node drains the anal canal (below the pectinate line)?
T cell dysfunction
Graves
Superficial inguinal
Activates Th1 helper cells; Macrophages

27. What are MHC's necessary for? By themselves?
Antiviral for uninfected cells (for future protection) and kills virally infected cells (NK activation)
T cell activation; no with CD 4 or CD 8
Tetanus - Botulinum - HBV - Rabies
A B and T cell disorder; defect in DNA repair enzymes; ataxia - telangactasia and IgA def; igA def. and increased AFP

28. What is the most common example of passive immunity?
Humoral
IgAs in mothers breast milk!
IL 5
Vasculitis of graft vessels with dense interstitial lymphocytic infiltrate; yes! with immunosuppressants

29. What is the main function of IL 8?
Nuclear remnants that are usually taken out of RBC before complete maturation by Macrophages
DM type I
Cytokine release syndrome due to initial release from initial binding (fever etc) and hypersensitivity reaction
A chemotactic factor for neutrophils

30. What kinds of receptors activate innate immunity?
Lack of response from lymphocytes when activated; because they are self reactive - this is a form of tolerance
pale central germinal centers
TLR ad nuclear receptors
Axillary

31. What are the autoantibodies for autoimmune hepatitis?
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
MHC class molecules bind to KIRS or CD94 to prevent killing
Anti smooth muscle
Mediates septic shock; activates the endothelium for adhesion and dilation and leukocyte recruitment results in vascular leak

32. What type of side chains are found on Fc region of an antibody?
CD56
Carbohydrate
Activate macrophages
IL 1 - IL 6 - IL 12 - TNF alpha; IL 6- Th2 cells; IL 12- B cells

33. What are the autoantibodies for systemic sclerosis?
Anti topoisomerase
Sinusitis - otitis media - pneumonia
Scratch test - histamine mediated wheal; radioimmunosorbent assay (detects specific IgEs in serum)
Lack of MHC class I constant region which it binds or a nonspecific activation signal (TLR)

34. Which are the only two antiinflammatory cytokines?
TGF beta and IL 10
Para aortic
heavy chains
RNA segment reassortment

35. What is the receptor for EBV? On what cells is that located?
CD21 on B cells (although there is T cell lymphocytosis in EBV)
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
Superficial inguinal
An alpha chain and a B2 microglobulin; on all nucleated cells; TCR and CD8; intracellular antigens

36. What are the autoantibodies for hashimotos?
Since cant cross placenta most likely means that child was forced early to produce due to an infection (most likely CMV)
Antimicrosomal and antithyroglobulin
Macrophages - Dendritic cells - B cells
Leukocyte adhesion defect; ataxia telangietasia; ataxia telangiectasia; chediak higashi syndrome; IgA def; Digeorge syndrome; Jobs; Chediak Higashi

37. What is the result of an IL 12 deficiency? What is the presentation? What are the labs?
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
Defect in BTK a tyrosine kinase gene; failed maturation of B cells; X linked recessive
Internal iliac
Decreased Th1 response; disseminated mycobacterial infections; decreased interferon gamma

38. What are the autoantibodies for Celiac disease?
Stimulate the liver to release acute phase reactants
Since cant cross placenta most likely means that child was forced early to produce due to an infection (most likely CMV)
Severe pyogenic infections early in life
Antigliadin - antiendomysial (both are IgAs - anti tissue transgluataminase igA)

39. What is a type I hypersensitivity reaction? What is atopic?
not Ab mediated
An anaphylactic immediate reaction; atopy refers to the inherited propensity to develop asthmatic or allergic reactions
Normal pro B (CD 19 +) - no mature B cells results in decreased total B cell level - and decreased amount of immunoglobulins in each class
Coarse Faces - cold (noninflamed d/t inability to attract neutrophils) staph abscesses - retained primary teeth - high igE - dermatologic problems (eczema)

40. What are four results of a splenectomy?
1) susceptibility to encapsulated organisms 2) Howell Jolly Bodies 3) Target cells 4) Thrombocytosis
Defect in BTK a tyrosine kinase gene; failed maturation of B cells; X linked recessive
Paracortex; viral infection
Septicemia with neisseria; because at least you have C3 to act like a neutrophilic chemotactic and an acute phase reactant

41. What do macrophages secrete that activate Th1 cells to secrete interferon gamma?
TNF alpha and IL1
A recomb cytokine of IL 2; RCC and metastatic melanoma
Cells that stil have weird parts of their membrane that macrophages usually bite off
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

42. What are the autoantibodies for goodpastures syndrome?
Complement activation (active in both)
Activate B cells - activate Macrophages - kill viruses directly - delayed cell mediated hypersensitivity - acute and chronic rejection
Anti alpha subunit 3 of collagen on type IV bm
P - ANCA (antimyeloperoxidase); in neutrophil; p= perinuclear

43. what cell surface marker is used for NK cells as it is unique to them?
Adaptive uses classic pathway to kill; innate uses alternative pathway to kill
Anti SS- A (anti RO) and Anti SS- B
CD56
Local infection/inflammation; infection of the ln itself; metastasis

44. What is an autograft? syngeneic graft? allograft? xenograft? What is an ex of an allograft? xenograft?
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
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
From self; from identical twin or clone; from nonidentical individual of same species; from different species; fetus; pig valve
opsonizes

45. 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
The antibodies (igM or IgG) either neutralize the target directly (cytoxic!) or recruit leukocytes (Neutrophils and Macrophages!) to incite tissue damage
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
except hyperacute

46. What are the T cell functions?
T cells react to the angtigen and activate leukocyted (macrophage acitivation)
Humoral
Rheumatic arthritis
Activate B cells - activate Macrophages - kill viruses directly - delayed cell mediated hypersensitivity - acute and chronic rejection

47. What is filgrastim and sargramostim? and What is it used for?
Antimicrosomal and antithyroglobulin
CD40 (on b cell) CD40 ligand on Th2 cell; and interleukins (4 -5 -6) from Th2 cell; CD40 is actually the second signal
Recomb cytokine of GCSF (granulocyte macrophage colony stimulating factor; for recovery of bone marrow
Delayed type hypersensitivity

48. How is the thymus organized? what happens in each section?
Cells that stil have weird parts of their membrane that macrophages usually bite off
Psoriasis - Ankylosis Spondylitis - IBD - Reiters; all seronegative spondylopathies
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
CD40 (on b cell) CD40 ligand on Th2 cell; and interleukins (4 -5 -6) from Th2 cell; CD40 is actually the second signal

49. What is the pathogenesis of chronic granulomatous disease; What is the presentation? What is the labs?
Adenosine deaminase deficiency (AR) - defective IL 2 receptor (X linked) - and failure to synthesize MHC II; both humoral and cell mediated deficiency
Septicemia with neisseria; because at least you have C3 to act like a neutrophilic chemotactic and an acute phase reactant
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
Lack of NADPH oxidase results in a lack of respiratory burst in neutrophils; susceptibility to catalase positive organisms (S. aureus - E. Coli - Aspergillus)

50. What is an example of a parasite showing antigenic variation?
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
Trypanosomes with programmed rearrangement (results in recurring fever -- sleeping sickness!)
Basophils! THey want IG E class switch!
Complement activation (active in both)