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 are the autoantibodies for drug induced lupus?
Rheumatic arthritis
Anti Jo -1
T
Antihistone

2. What are some sinopulmonary infections?
IgE; by activating eosinophils
Fibrosis of blood vessels and graft tissue from ischemia; obliterative vascular fibrosis with intimal thickening
Inferior mesenteric
Sinusitis - otitis media - pneumonia

3. ________ regulate the cell mediated response.
Opsonize bacteria (for enhanced phagocytosis) - neutralize viruses (igG) - activate complement (igM and igG) - sensitize mast cells (igE)
Legionella - N. gonorrhea - L. monocytogenes - viruses - protozoa (leismaniasis)
Activates Macrophages and Th1 cells; suppresses Th2 cells; antiviral and antitumor
Humoral

4. What are the main Cell surface proteins on T cells?
MHC II - B7
Basophils! THey want IG E class switch!
TCR - CD4/8 - CD28 (binds B7) - CD3 (for intracellular transduction) - CD40L
IgA

5. Describe the complement independent Type II hypersenstivity reaction. Give an example.
A recomb cytokine of IL 2; RCC and metastatic melanoma
opsonizes
The antibodies (igM or IgG) either neutralize the target directly (cytoxic!) or recruit leukocytes (Neutrophils and Macrophages!) to incite tissue damage
Lack of MHC class I constant region which it binds or a nonspecific activation signal (TLR)

6. If the alternative pathway is constitively active - how come normal cells don't get attacked with MAC?
Defect in CD40L results in inability to class switch; a lot of IgM and no IgG - A - E
DAF and C1 esterase inhibitor on cells prevent complement activation on their surfaces (microbial surfaces lack this)
IgM
Immunoflourescent staining of tissue biopsies

7. What are the autoantibodies for systemic sclerosis?
Cyclosporine and tacrolimus; sirolimus (as well as hyperlipidemia)
Anti topoisomerase
Popliteal
isotype

8. what happens in a deficiency of C1 esterase inhibitor? DAF?
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
2 heavy chains and two light chains
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
Hereditary angioedema; PNH

9. What cytokines do macrophages release? who else can secrete IL 6? IL 12?
IgM and IgA
Anti IF
The patient could become cyanotic in the OR!
IL 1 - IL 6 - IL 12 - TNF alpha; IL 6- Th2 cells; IL 12- B cells

10. The idiotype; the Fc portion determines the...
isotype
Type IV
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
Fever - urticaria - arthralgias - proteinuria - lymphadenopathy

11. What are howell jolly bodies?
Nuclear remnants that are usually taken out of RBC before complete maturation by Macrophages
Its a serine protease that activates apoptosis; NK and CD8
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
Suppresses immune response (also specifically Th1 cells) and activates Th2; regulatory T cells

12. Which Thelper cell activated Macrophages? by secreting what? what else does Th1 secrete? For what?
IgM and IgD
Anti Ach receptor
Th1; interferon gamma; IL 2 for cytotoxic T cell activation
Proteins; IgG - IgM - endotoxin (microbial surfaces in general - nonspecific ones also) - mannose binding Lectin; classic - alternative - MB pathway (resp)

13. Type Iv hypersensitivity is...
Make antibody - allergy type 1 (igE) - Cytotoxic and immunecomplex hypersensitivity type II and III (igG); hyperacute organ rejection is Ab mediated
1) susceptibility to encapsulated organisms 2) Howell Jolly Bodies 3) Target cells 4) Thrombocytosis
delayed!
Periarteriolar lymphatic sheath in the white pulp that surround that dead end of the capillaries in the red pulp - contain T cells

14. From where do cytokines come from?
Lymphocytes
The patient could become cyanotic in the OR!
Coarse Faces - cold (noninflamed d/t inability to attract neutrophils) staph abscesses - retained primary teeth - high igE - dermatologic problems (eczema)
Stimulate the liver to release acute phase reactants

15. What part of the lymph node specifically expands during a cellular immune response? when would this occur?
Anti U1 RNP (ribonucleoprotein)
Paracortex; viral infection
IgE; by activating eosinophils
Psoriasis - Ankylosis Spondylitis - IBD - Reiters; all seronegative spondylopathies

16. 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?
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
From self; from identical twin or clone; from nonidentical individual of same species; from different species; fetus; pig valve
IgM
Humoral

17. What is the main function of interferons?
Not thymus - BM
Remove encapsulated bacateria
Lack of MHC class I constant region which it binds or a nonspecific activation signal (TLR)
Antiviral for uninfected cells (for future protection) and kills virally infected cells (NK activation)

18. 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)?
Its involved in inflammation and results in anaphylaxis and neutrophil chemotaxis.
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
Isotype switching (activated by Th2 cell signals and cytokines) - somatic hypermutation
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

19. What does granzyme do? who secretes it?
Cytokine release syndrome due to initial release from initial binding (fever etc) and hypersensitivity reaction
Its a serine protease that activates apoptosis; NK and CD8
Hemochromatosis
Recurrent infections to every type of antigen; bone marrow transplant (be weary of GVH disease!)

20. What are some catalase positive organisms?
Anti mitochondrial
Both decrease cd8 tcell prolif but one through mtor and the other through calcineurin (resp)
Antimicrobial also secreted by CD8 and NK cells that induces apoptsosis
S. aureus - E. Coli - aspergillus

21. What does IL 5 do?
Vasculitis of graft vessels with dense interstitial lymphocytic infiltrate; yes! with immunosuppressants
C5a
Acts as second signal on B cells to induce class switching to IgA; also stimulates eosinophils
Recomb cytokine of GCSF (granulocyte macrophage colony stimulating factor; for recovery of bone marrow

22. What cytokines to Th2 secrete?
IL 4 - 5 - 10 - 6
Fc
Patient has had previous exposure to blood products which result in presence of preformed anti HLA cytotoxic Abs
Glycoproteins; HLA

23. What do macrophages secrete that activate Th1 cells to secrete interferon gamma?
TLR ad nuclear receptors
TNF alpha and IL1
Antimicrosomal and antithyroglobulin
neutrophilia!

24. what mediates the type II hypersensitivity? What are the two different methods?
Influenza; antigenic shift; antigenic drift
Celiac
Antibody mediated cytotoxicity; either complement dependent or complement independent
A j chain

25. In general What are T cells good for?
Immunosuppression after kidney transplantation
Surrounds the red pulp and begins with PALS and then turns into follicles with B cells/follicles
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
Anti viral and anti tumor

26. what characterizes an arthus reaction?
type four
Edema and necrosis in that region
Activate B cells - activate Macrophages - kill viruses directly - delayed cell mediated hypersensitivity - acute and chronic rejection
C5a

27. What are the autoantibodies for primary biliary cirrhosis?
Anti mitochondrial
Recurrent infections to every type of antigen; bone marrow transplant (be weary of GVH disease!)
not Ab mediated
Antimicrobial also secreted by CD8 and NK cells that induces apoptsosis

28. What is hereditary angioedema? What are the C3 levels?
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
S. aureus - E. Coli - aspergillus
Its a serine protease that activates apoptosis; NK and CD8
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

29. What is the common variable immunodeficiency ? How is it different from Brutons?
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
Both decrease cd8 tcell prolif but one through mtor and the other through calcineurin (resp)
2 heavy chains and two light chains
IL 1 - IL 6 - IL 12 - TNF alpha; IL 6- Th2 cells; IL 12- B cells

30. What are the autoantibodies for sjorgens syndrome?
IL 5
Make antibody - allergy type 1 (igE) - Cytotoxic and immunecomplex hypersensitivity type II and III (igG); hyperacute organ rejection is Ab mediated
Carbohydrate
Anti SS- A (anti RO) and Anti SS- B

31. What is the pathogenesis of chronic granulomatous disease; What is the presentation? What is the labs?
Trypanosomes with programmed rearrangement (results in recurring fever -- sleeping sickness!)
Lack of NADPH oxidase results in a lack of respiratory burst in neutrophils; susceptibility to catalase positive organisms (S. aureus - E. Coli - Aspergillus)
Popliteal
Not thymus - BM

32. What are the main cell surface proteins on B cells?
IgG
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
Ig - CD19 - CD20 - CD21 - CD40 - MHC II - B7
Alternative splicing of mRNA

33. What is the main function of TNF alpha? How does it do this?
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
Receiving preformed Antibodies
P - ANCA (antimyeloperoxidase); in neutrophil; p= perinuclear
Mediates septic shock; activates the endothelium for adhesion and dilation and leukocyte recruitment results in vascular leak

34. What is MHC I made out of? Where is it found? What does it bind to? What type of antigens does it present?
Interferon gamma; Th1
An alpha chain and a B2 microglobulin; on all nucleated cells; TCR and CD8; intracellular antigens
pale central germinal centers
TCR - CD4/8 - CD28 (binds B7) - CD3 (for intracellular transduction) - CD40L

35. 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
Lack of response from lymphocytes when activated; because they are self reactive - this is a form of tolerance
Surrounds the red pulp and begins with PALS and then turns into follicles with B cells/follicles
A recomb cytokine of IL 2; RCC and metastatic melanoma

36. What does IgA pick up from epithelial cells before being secreted?
Lack of response from lymphocytes when activated; because they are self reactive - this is a form of tolerance
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
Secretory component
Fibrosis of blood vessels and graft tissue from ischemia; obliterative vascular fibrosis with intimal thickening

37. What are C1 - C2 - C3 - C4 important for?
Viral neutralization of igM and IgG!
Cross link antigens which increases their phagocytability; activate complement for MAC attack; opsonization; neutralization
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
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

38. What are the autoantibodies for other vasculitides?
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
P - ANCA (antimyeloperoxidase); in neutrophil; p= perinuclear
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
An anaphylactic immediate reaction; atopy refers to the inherited propensity to develop asthmatic or allergic reactions

39. Name 5 ways Antibody diversity is generated?
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
Digeorge syndrome - 22q11 deletion resulting in failure to develop 3rd and 4th pharyngeal pouches; cardiac and great vessel congenital defects - tetany from hypocalcemia - recurrent viral/fungal infections from T cell deficiency; hypoPTH - hypoCa - a
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
Anti smooth muscle

40. What is filgrastim and sargramostim? and What is it used for?
Recomb cytokine of GCSF (granulocyte macrophage colony stimulating factor; for recovery of bone marrow
Alternative splicing of mRNA
Glycoproteins; HLA
IL 3; supports growth and differentiation of bone marrow stem cells

41. which of the hypersensitivity reactions is not Ab mediated?
Daclizumab; prevent ACUTE rejection of renal transplant
Type IV
Defect in BTK a tyrosine kinase gene; failed maturation of B cells; X linked recessive
IgM

42. What are the main symptoms of T cell immunodeficiencies?
Recomb cytokine of GCSF (granulocyte macrophage colony stimulating factor; for recovery of bone marrow
Liver! (they are proteins circulating in the blood)
Kill them because they have CD16 on them that recognize the FcG portion
Intracellular pathogens (acute and chronic viruses and virally induced cancers)

43. What is recomb alpha interferon used for?
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
Stimulate the liver to release acute phase reactants
HBV - HBC - Kaposis - leukemias - malignant melanoma - hairy cell leukemia and condyluma accuminata
Th1; interferon gamma; IL 2 for cytotoxic T cell activation

44. which antibodies prevent antigens from binding mucosal surfaces?
CD40 (on b cell) CD40 ligand on Th2 cell; and interleukins (4 -5 -6) from Th2 cell; CD40 is actually the second signal
Septicemia with neisseria; because at least you have C3 to act like a neutrophilic chemotactic and an acute phase reactant
IgA
TLR ad nuclear receptors

45. 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
Activates Th1 helper cells; Macrophages
Paracortex; viral infection
Since cant cross placenta most likely means that child was forced early to produce due to an infection (most likely CMV)

46. IgM can fix complement but...
Para aortic
cannot cross placenta
Hyperacute; presence of preformed antibodies in the recipient ( to blood groups or HLA )
IgE

47. What are the PALS?
Immune complex - Arthus reaction and Serum sickness; they are all a result of antibody- antigen complex deposition resulting in complement activation
Daclizumab; prevent ACUTE rejection of renal transplant
encapsulated
Periarteriolar lymphatic sheath in the white pulp that surround that dead end of the capillaries in the red pulp - contain T cells

48. with failed maturation of B cells in Brutons agammaglobulinemia - What is its effect on immune pathways and why?
Recurrent infections to every type of antigen; bone marrow transplant (be weary of GVH disease!)
Chronic granulomatous disease
Its main effect is a defect in Ab opsonization for killing
Surrounds the red pulp and begins with PALS and then turns into follicles with B cells/follicles

49. which cells have more complete tolerance - B or T cells?
DM type I
T
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
Hereditary angioedema; PNH

50. The Fc region is found on the...
Th1; interferon gamma; IL 2 for cytotoxic T cell activation
Trypanosomes with programmed rearrangement (results in recurring fever -- sleeping sickness!)
carboxy terminal
Acts as second signal on B cells to induce class switching to IgE and IgG