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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. which type of immunity is slow but long lasting? as opposed to...
secondary
Anti viral and anti tumor
Active; passive - fast but short half life (3 weeks!)
Defect in BTK a tyrosine kinase gene; failed maturation of B cells; X linked recessive

2. Which diseases are associated with DR4?
T
Th cells fail to produce interferon gamma; a lot of IgE
DM type I and RA
Anti smooth muscle

3. Name three things that IL 1 does as a cytokine. other than the liver - who secretes IL 1
IL 15; IL 12 - interferon Beta and interferon alpha
Anti viral and anti tumor
Induces fever - chemokine secretion to recruit - activates adhesion molecules; macrophages
Carbohydrate

4. IgM can exist as a _______ also
Cyclosporine - OKT3
pentamer
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

5. What does interferon gamma do to be antiviral?
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
Increases expression of MHC I and MHC II and also activates NK cells
Lack of NADPH oxidase results in a lack of respiratory burst in neutrophils; susceptibility to catalase positive organisms (S. aureus - E. Coli - Aspergillus)
Acts as second signal on B cells to induce class switching to IgE and IgG

6. What are MHC Class molecules (ie what macromolecule are they made out of)? what gene are responsible for MHC?
Sinusitis - otitis media - pneumonia
Glycoproteins; HLA
Macrophages - Dendritic cells - B cells
Recomb cytokine of GCSF (granulocyte macrophage colony stimulating factor; for recovery of bone marrow

7. is IgM an opsonizer?
Negative!
The place of T cell diff and maturation; ant mediastinum above heart; yes; 2
IgG
cannot cross placenta

8. What is serum sickness? give an example.
Nuclear remnants that are usually taken out of RBC before complete maturation by Macrophages
Defect in BTK a tyrosine kinase gene; failed maturation of B cells; X linked recessive
B - T - and NK cells
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

9. What does IL 10 do? who is secreted by?
dimer
Suppresses immune response (also specifically Th1 cells) and activates Th2; regulatory T cells
Negative nitroblue tetrazolium reduction test
Anticentromere; anti Scl -70 (anti DNA topoisomerase I)

10. 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
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
Isotype switching (activated by Th2 cell signals and cytokines) - somatic hypermutation
Steroid responsive nephrotic syndrome

11. Describe the complement independent Type II hypersenstivity reaction. Give an example.
Recomb cytokine of GCSF (granulocyte macrophage colony stimulating factor; for recovery of bone marrow
The antibodies (igM or IgG) either neutralize the target directly (cytoxic!) or recruit leukocytes (Neutrophils and Macrophages!) to incite tissue damage
IgG
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

12. What is the pathogenesis of chronic transplant rejection? When does it occur? is it reversible?
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
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 :(
Nuclear remnants that are usually taken out of RBC before complete maturation by Macrophages
Since it is a comp dependent type II hypersensitivity reaction; C3a brings anaphylotoxins that bring in mediators of shock

13. What are the autoantibodies for pernicious anemia?
Anti IF
Septicemia with neisseria; because at least you have C3 to act like a neutrophilic chemotactic and an acute phase reactant
T cell dysfunction
C - ANCA (antiproteinase); in neutrophil; c= cytoplasmic

14. Leukocyte adhesion defect presents with...
Pernicious Anemia and Hashimotos
Glycoproteins; HLA
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 :(
neutrophilia!

15. What are the two signals required for B cell class switching? Which is the second signal?
Histamine; post capillary venules - vasodilation
IgM and IgD
CD40 (on b cell) CD40 ligand on Th2 cell; and interleukins (4 -5 -6) from Th2 cell; CD40 is actually the second signal
Thrombocytopenia

16. What are target cells?
Septicemia with neisseria; because at least you have C3 to act like a neutrophilic chemotactic and an acute phase reactant
Cells that stil have weird parts of their membrane that macrophages usually bite off
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
Hyperacute; presence of preformed antibodies in the recipient ( to blood groups or HLA )

17. So antibodies are the effectors for the humoral response. List some of their functions.
Scratch test - histamine mediated wheal; radioimmunosorbent assay (detects specific IgEs in serum)
Cross link antigens which increases their phagocytability; activate complement for MAC attack; opsonization; neutralization
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
Septicemia with neisseria; because at least you have C3 to act like a neutrophilic chemotactic and an acute phase reactant

18. What is the pathogenesis of acute transplant rejection? When does it occur?
If there is class switching and plasma cell production (that is when memory cells are produced)
Cell mediated due to T cell cytotoxicity reacting to foreign MHCs; few weeks after
Decreased Th1 response; disseminated mycobacterial infections; decreased interferon gamma
Superficial inguinal

19. What are the autoantibodies for drug induced lupus?
Hemochromatosis
Both decrease cd8 tcell prolif but one through mtor and the other through calcineurin (resp)
Axillary
Antihistone

20. A lymph node is a ________ lymphoid organ.
secondary
Anti mitochondrial
Tumor cells and virally infected cells; perforin pore to secrete granzymes through it; apoptosis
Chronic granulomatous disease

21. What do multimeric antibodies require for assembly?
Humoral
Lack of MHC class I constant region which it binds or a nonspecific activation signal (TLR)
T cell dysfunction
A j chain

22. What are the autoantibodies for myasthenia gravis?
Anti Ach receptor
type four
Paracortex
Internal iliac

23. What does IL 2 do?
Recurrent sinopulmonary bacterial infections after 6 months (d/t mothers igGs transplacental) due to opsonization defect
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
Activates cytotoxic CD 8 T cells as second signal
Anti nuclear Antibodies (ANA); Anti dsDNA - anti Smith

24. what will NK cells do to cells covered in IgG Ab? why?
Its a serine protease that activates apoptosis; NK and CD8
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
Kill them because they have CD16 on them that recognize the FcG portion
Sinusitis - otitis media - pneumonia

25. Type IV hypersensitivity is i...
not Ab mediated
mesenchymal
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
opsonizes

26. What is the most common example of passive immunity?
Negative nitroblue tetrazolium reduction test
IgAs in mothers breast milk!
Proteins; IgG - IgM - endotoxin (microbial surfaces in general - nonspecific ones also) - mannose binding Lectin; classic - alternative - MB pathway (resp)
Anti IF

27. what bacteria are a splenectomy patient most susceptible to? why?
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
Antidesmoglein
Barrel hoop basement membrane fenestrations
secondary

28. What are the autoantibodies for pemphigus bulgaris?
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
Antidesmoglein
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
Histamine; post capillary venules - vasodilation

29. What are the three immune privileged sites? why are they called that? what happens after infection in these areas?
Carbohydrate
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
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
Interferon gamma and IL 2

30. what cytokine does basophils secrete?
Immunoflourescent staining of tissue biopsies
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)
IgA
IL 4

31. What is hereditary angioedema? What are the C3 levels?
Macrophages - Dendritic cells - B cells
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
Sinusitis - otitis media - pneumonia
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

32. What are the autoantibodies for hashimotos?
Antidesmoglein
Antimicrosomal and antithyroglobulin
Superficial inguinal
IgG

33. What lymph node drains the lateral side of the dorsum of the foot?
Acts as second signal on B cells to induce class switching to IgA; also stimulates eosinophils
Celiac
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
Popliteal

34. What is the defect in Brutons agammaglobulinemia? What is its effect on B cells? What is its inheritance pattern?
Fc
Defect in BTK a tyrosine kinase gene; failed maturation of B cells; X linked recessive
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
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

35. Which Thelper cell activated Macrophages? by secreting what? what else does Th1 secrete? For what?
Th1; interferon gamma; IL 2 for cytotoxic T cell activation
CRP - C3b - IgM
IL 1 and IL 6
MHC I/CD8 and IL2/IL 2 Receptor (IL 2 is from Th1!); cytoxicity!

36. How do we use thymus dependent antigens to prevent infection from organisms that lack a peptide component?
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
Negative!
IL 5
Patient has had previous exposure to blood products which result in presence of preformed anti HLA cytotoxic Abs

37. Which TCR MHC system is important for viral immunity? neoplastic? donor graft cells?
delayed!
All MHC 1/CD8
Periarteriolar lymphatic sheath in the white pulp that surround that dead end of the capillaries in the red pulp - contain T cells
False! B cell class switching requires a second signal

38. What do mature naive B lymphocytes express?
IgM and IgD
From self; from identical twin or clone; from nonidentical individual of same species; from different species; fetus; pig valve
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
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

39. What is the main function of IL 12? other than macrophages who else can release IL 12?
Secretory component
Induce differentiation of T cells into Th1 helper cells and activates NK cells also; B cells
Type IV
Stimulate the liver to release acute phase reactants

40. Give an example of someone who could get hyperacute transplant rejection.
Legionella - N. gonorrhea - L. monocytogenes - viruses - protozoa (leismaniasis)
All MHC 1/CD8
Previous transfusion; pregnant woman whose fetus had paternal antigens
Axillary

41. which immunodeficiency presents with delayed separation of the umbilicus? ataxia? telangiectasia?albinism? anaphylaxis on exposure to blood products with IgA? tetany?retained primary teeth? peripheral neuropathy?
The antibodies (igM or IgG) either neutralize the target directly (cytoxic!) or recruit leukocytes (Neutrophils and Macrophages!) to incite tissue damage
Leukocyte adhesion defect; ataxia telangietasia; ataxia telangiectasia; chediak higashi syndrome; IgA def; Digeorge syndrome; Jobs; Chediak Higashi
Defect in CD40L results in inability to class switch; a lot of IgM and no IgG - A - E
If there is class switching and plasma cell production (that is when memory cells are produced)

42. what ensure that a memory response is generated?
Cyclosporine and tacrolimus; sirolimus (as well as hyperlipidemia)
Patient has had previous exposure to blood products which result in presence of preformed anti HLA cytotoxic Abs
Anti Jo -1
If there is class switching and plasma cell production (that is when memory cells are produced)

43. What are the autoantibodies for goodpastures syndrome?
Anti alpha subunit 3 of collagen on type IV bm
cannot cross placenta
Immune complex - Arthus reaction and Serum sickness; they are all a result of antibody- antigen complex deposition resulting in complement activation
carboxy terminal

44. Name the three opsonins
Tumor cells and virally infected cells; perforin pore to secrete granzymes through it; apoptosis
CRP - C3b - IgM
TCR - CD4/8 - CD28 (binds B7) - CD3 (for intracellular transduction) - CD40L
CD21 on B cells (although there is T cell lymphocytosis in EBV)

45. which of the IL2 inhibitors produce nephrotoxicity? thrombocytopenia/leukopenia?
Antihistone
Humoral
Immunosuppression after kidney transplantation
Cyclosporine and tacrolimus; sirolimus (as well as hyperlipidemia)

46. what happens in order for class switching to occur (after being activated by IL and cd40 L)?
Alternative splicing of mRNA
Remove encapsulated bacateria
IgM
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

47. What is a factor that is a predictor for a bad transplantation?
Patient has had previous exposure to blood products which result in presence of preformed anti HLA cytotoxic Abs
DM type I and RA
Paracortex
False! B cell class switching requires a second signal

48. What lymph node drains the testes?
T cell activation; no with CD 4 or CD 8
Para aortic
...
Influenza; antigenic shift; antigenic drift

49. What is oprelevkin? and What is it used for?
Superficial inguinal
Recom IL 11; thrombocytopenia
IL 5
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

50. What are the autoantibodies for Mixed connective tissue disease?
Anti U1 RNP (ribonucleoprotein)
Trypanosomes with programmed rearrangement (results in recurring fever -- sleeping sickness!)
Surrounds the red pulp and begins with PALS and then turns into follicles with B cells/follicles
CRP - C3b - IgM