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. What is recomb beta interferon used for?
Axillary
Immune complex - Arthus reaction and Serum sickness; they are all a result of antibody- antigen complex deposition resulting in complement activation
Proteins; IgG - IgM - endotoxin (microbial surfaces in general - nonspecific ones also) - mannose binding Lectin; classic - alternative - MB pathway (resp)
MS

2. IgG...
opsonizes
Type IV
CD56
IL 1 and IL 6

3. What is the most common selective Ig deficiency? What is the presentation?
Inferior mesenteric
Anti viral and anti tumor
IgA; sinus and lung infections from lack of secretory defense - milk allergies and diarrhea from giardiasis; Anaphylasix on exposure to blood products with igA
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

4. What is the white pulp of the spleen?
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
Surrounds the red pulp and begins with PALS and then turns into follicles with B cells/follicles
Type III hypersensitivity where an internal antigen antibody complexes activate classical complement pathway resulting in C3a neutrophilic chemotaxis and neutrophilic lysosomal death. SLE
Opsonize bacteria (for enhanced phagocytosis) - neutralize viruses (igG) - activate complement (igM and igG) - sensitize mast cells (igE)

5. which interleukin receptor is required for NK development? activation?
Edema and necrosis in that region
IL 15; IL 12 - interferon Beta and interferon alpha
MHC II - B7
SP infections

6. The secondary follicles have __________; primary follicles are dense
MHC class molecules bind to KIRS or CD94 to prevent killing
pale central germinal centers
Anti TSh receptor
IL 15; IL 12 - interferon Beta and interferon alpha

7. What are the cell surface proteins for Macrophages? which two are for opsonins?
Induce differentiation of T cells into Th1 helper cells and activates NK cells also; B cells
Paracortex
MHC II - B7 - CD40 and CD14; CD40 and D14 for FcG and C3b resp
CD40 (on b cell) CD40 ligand on Th2 cell; and interleukins (4 -5 -6) from Th2 cell; CD40 is actually the second signal

8. explain the process from beginning (ie phagocytosis of the peptide) to end of how Abs are formed in Goodpasteurs.
CRP - C3b - IgM
carboxy terminal
active complement pathway
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

9. What does IL 10 do? who is secreted by?
MS
Ischemia and necrosis of graft due to occlusion of vessels and fibrinoid necrosis and thrombosis within the vessels
Suppresses immune response (also specifically Th1 cells) and activates Th2; regulatory T cells
Para aortic

10. What is thrombopoietin used for?
IgAs in mothers breast milk!
Thrombocytopenia
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
Celiac

11. What is three common causes of severe combined immunodef? What is the result of all three?
Th cells fail to produce interferon gamma; a lot of IgE
Adenosine deaminase deficiency (AR) - defective IL 2 receptor (X linked) - and failure to synthesize MHC II; both humoral and cell mediated deficiency
Stimulate the liver to release acute phase reactants
From self; from identical twin or clone; from nonidentical individual of same species; from different species; fetus; pig valve

12. other than C3a - what other complement acts as an anaphyloxin?
C5a
Anti TSh receptor
SP infections
T cell dysfunction

13. Which disease is associated with DR7?
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
Hemochromatosis
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
Steroid responsive nephrotic syndrome

14. What are the autoantibodies for sjorgens syndrome?
Humoral
Alternative splicing of mRNA
Anti SS- A (anti RO) and Anti SS- B
Activates Th1 helper cells; Macrophages

15. Which disease is associated withB B27?
Defect in BTK a tyrosine kinase gene; failed maturation of B cells; X linked recessive
IL 15; IL 12 - interferon Beta and interferon alpha
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
Psoriasis - Ankylosis Spondylitis - IBD - Reiters; all seronegative spondylopathies

16. What part of the complement system also acts as an opsonin? What is opsonization? can you Name two other opsonins?
RNA segment reassortment
Not thymus - BM
C3b; coating of a pathogen with molecules that promotes phagocytosis; IgG and CRP
Psoriasis - Ankylosis Spondylitis - IBD - Reiters; all seronegative spondylopathies

17. How is the thymus organized? what happens in each section?
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
Histamine; post capillary venules - vasodilation
Glycoproteins; HLA
Intracellular pathogens (acute and chronic viruses and virally induced cancers)

18. For which toxins are preformed antibodies (passive) given?
acute phase reactants
Tetanus - Botulinum - HBV - Rabies
Increases expression of MHC I and MHC II and also activates NK cells
Carbohydrate

19. 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
pale central germinal centers
IL 4 -5 -6 for B cell class switching - IL 10 to inhibit TH1
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!

20. What lymph node drains the stomach?
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
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
Celiac
Negative selection

21. What is a type I hypersensitivity reaction? What is atopic?
An anaphylactic immediate reaction; atopy refers to the inherited propensity to develop asthmatic or allergic reactions
Anti viral and anti tumor
MHC II - B7 - CD40 and CD14; CD40 and D14 for FcG and C3b resp
Viral neutralization of igM and IgG!

22. Other than stimulating fever - what else does IL 6 do?
Stimulate the liver to release acute phase reactants
IgE
DAF and C1 esterase inhibitor on cells prevent complement activation on their surfaces (microbial surfaces lack this)
Antidote for digoxin intoxication

23. What is the pathology of acute transplant rejection? is it reversible?
Its a serine protease that activates apoptosis; NK and CD8
Since it is a comp dependent type II hypersensitivity reaction; C3a brings anaphylotoxins that bring in mediators of shock
From self; from identical twin or clone; from nonidentical individual of same species; from different species; fetus; pig valve
Vasculitis of graft vessels with dense interstitial lymphocytic infiltrate; yes! with immunosuppressants

24. What is the presentation of common variable immunodef? and What are the labs?
Kill them because they have CD16 on them that recognize the FcG portion
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
Cyclosporine - OKT3
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

25. What are the two signals to kill for NK cells?
Lack of MHC class I constant region which it binds or a nonspecific activation signal (TLR)
Periarteriolar lymphatic sheath in the white pulp that surround that dead end of the capillaries in the red pulp - contain T cells
Internal iliac
Daclizumab; prevent ACUTE rejection of renal transplant

26. ________ regulate the cell mediated response.
Histamine (causes vasodilation) - leukotrienes (causes bronchoconstriction) - chemotaxins for eos - and heparin (increased blood flow needs to be anticoagulated!)
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
Humoral
Anti glutamate carboxylase and anti insulin

27. What are the two signals required for T cells? what happens after?
MHC I/CD8 and IL2/IL 2 Receptor (IL 2 is from Th1!); cytoxicity!
Fab portion
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
TLR ad nuclear receptors

28. What is the pathogenesis of IgG AIHA ABO hemolytic disease of a newborn? describe what happens.
Stimulate the liver to release acute phase reactants
Negative selection
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
By transcytosis

29. What are some catalase positive organisms?
IgG
cannot cross placenta
S. aureus - E. Coli - aspergillus
IgG

30. The idiotype; the Fc portion determines the...
isotype
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
Anti Jo -1
Liver! (they are proteins circulating in the blood)

31. What is digoxin immune Fab used for?
Antidote for digoxin intoxication
Carbohydrate
Interferon gamma and IL 2
Opsonize bacteria (for enhanced phagocytosis) - neutralize viruses (igG) - activate complement (igM and igG) - sensitize mast cells (igE)

32. What are the autoantibodies for wegeners granulomatosis?
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
C - ANCA (antiproteinase); in neutrophil; c= cytoplasmic
No because no peptide fragment!
IgE; by activating eosinophils

33. What is the end result of complement activation? what bugs are this important for? through what pathway and why?
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)
Anti mitochondrial
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
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

34. What are the sinusoids of the spleen? What is the difference between a spleen and a lymph node?
An anaphylactic immediate reaction; atopy refers to the inherited propensity to develop asthmatic or allergic reactions
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
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
1) susceptibility to encapsulated organisms 2) Howell Jolly Bodies 3) Target cells 4) Thrombocytosis

35. What is the pathogenesis of a candida skin test?
P - ANCA (antimyeloperoxidase); in neutrophil; p= perinuclear
MHC I/CD8 and IL2/IL 2 Receptor (IL 2 is from Th1!); cytoxicity!
Delayed type hypersensitivity
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

36. What are the main symptoms of B cell immunodeficiencies?
IL 1 and IL 6
SP infections
C5a
An anaphylactic immediate reaction; atopy refers to the inherited propensity to develop asthmatic or allergic reactions

37. What is the presentation of Brutons agammaglobulinemia?
Carbohydrate
The igA found in breast milk
Th cells fail to produce interferon gamma; a lot of IgE
Recurrent sinopulmonary bacterial infections after 6 months (d/t mothers igGs transplacental) due to opsonization defect

38. What are the autoantibodies for drug induced lupus?
Anti smooth muscle
Intracellular pathogens (acute and chronic viruses and virally induced cancers)
Antihistone
Kill them because they have CD16 on them that recognize the FcG portion

39. What does granulysin do?
Salmonella - 2 flagellar variants; Borrelia (relapsing fever); and Neisseria gonorrhoaea - pilus protein
carboxy terminal
Antimicrobial also secreted by CD8 and NK cells that induces apoptsosis
...

40. Which disease is associated with B8?
Graves
P - ANCA (antimyeloperoxidase); in neutrophil; p= perinuclear
isotype
IgG

41. If the alternative pathway is constitively active - how come normal cells don't get attacked with MAC?
Alternative splicing of mRNA
...
DAF and C1 esterase inhibitor on cells prevent complement activation on their surfaces (microbial surfaces lack this)
CD56

42. What is the result of an IL 12 deficiency? What is the presentation? What are the labs?
Edema and necrosis in that region
Decreased Th1 response; disseminated mycobacterial infections; decreased interferon gamma
opsonizes
T cell precursor

43. What is hereditary angioedema? What are the C3 levels?
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
Psoriasis - Ankylosis Spondylitis - IBD - Reiters; all seronegative spondylopathies
Anti Ach receptor
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

44. Which helper T cells' development is induced by IL 4? IL 12?
Acts as second signal on B cells to induce class switching to IgE and IgG
Bind FcG for antibody dependent cellular cytotoxicity
Chronic granulomatous disease
Th2; Th1

45. What bugs can actually infect the lymph node itself?
Wiskott Aldrich syndrome
Edema and necrosis in that region
RNA segment reassortment
Mycobacterium Tuberculosis - Mycobacterium Avium Intracellulare; Toxoplasmosis Gondii

46. What are the PALS?
Edema and necrosis in that region
The place of T cell diff and maturation; ant mediastinum above heart; yes; 2
Anti smooth muscle
Periarteriolar lymphatic sheath in the white pulp that surround that dead end of the capillaries in the red pulp - contain T cells

47. So antibodies are the effectors for the humoral response. List some of their functions.
...
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
Cross link antigens which increases their phagocytability; activate complement for MAC attack; opsonization; neutralization
IgG

48. What are the autoantibodies for graves?
Anti TSh receptor
MS
Anticentromere; anti Scl -70 (anti DNA topoisomerase I)
Hemochromatosis

49. How do we use thymus dependent antigens to prevent infection from organisms that lack a peptide component?
Anti SS- A (anti RO) and Anti SS- B
IgAs in mothers breast milk!
cannot cross placenta
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

50. Which Thelper cell activated Macrophages? by secreting what? what else does Th1 secrete? For what?
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
Th1; interferon gamma; IL 2 for cytotoxic T cell activation
Negative selection
IgM