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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.
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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 the two fates of the RBCs that go through the spleen? what happens eventually to all of them>
Anti viral and anti tumor
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
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
CD56

2. What is an autograft? syngeneic graft? allograft? xenograft? What is an ex of an allograft? xenograft?
From self; from identical twin or clone; from nonidentical individual of same species; from different species; fetus; pig valve
Induce differentiation of T cells into Th1 helper cells and activates NK cells also; B cells
Sinusitis - otitis media - pneumonia
Rheumatic arthritis

3. Which are the only two antiinflammatory cytokines?
TGF beta and IL 10
IgG
Type III hypersensitivity where an internal antigen antibody complexes activate classical complement pathway resulting in C3a neutrophilic chemotaxis and neutrophilic lysosomal death. SLE
Anti U1 RNP (ribonucleoprotein)

4. What is filgrastim and sargramostim? and What is it used for?
IL 15; IL 12 - interferon Beta and interferon alpha
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
Severe recurrent pyogenic sinus and resp tract And increased susceptibility to type III hypersensitivity like SLE
Recomb cytokine of GCSF (granulocyte macrophage colony stimulating factor; for recovery of bone marrow

5. Only the _______ contribute to the Fc region
Both decrease cd8 tcell prolif but one through mtor and the other through calcineurin (resp)
Make antibody - allergy type 1 (igE) - Cytotoxic and immunecomplex hypersensitivity type II and III (igG); hyperacute organ rejection is Ab mediated
heavy chains
Mycobacterium Tuberculosis - Mycobacterium Avium Intracellulare; Toxoplasmosis Gondii

6. How do we use thymus dependent antigens to prevent infection from organisms that lack a peptide component?
A - B - C; all the D's
Septicemia with neisseria; because at least you have C3 to act like a neutrophilic chemotactic and an acute phase reactant
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
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

7. What are the main cell surface proteins on B cells?
Kill them because they have CD16 on them that recognize the FcG portion
Ig - CD19 - CD20 - CD21 - CD40 - MHC II - B7
...
IgM and IgG

8. What is wiskott aldrich syndrome? What is its mode of inheritance? What is the pathogenesis of disease? What is its triad of presentation? what labs does it present with?
Negative!
A B and T cell disorder; X linked recessive; progressive deletion of B and T cells; thrombocytopenic purpura - infections - eczema; high IgE and IgA but low IgM
Make antibody - allergy type 1 (igE) - Cytotoxic and immunecomplex hypersensitivity type II and III (igG); hyperacute organ rejection is Ab mediated
T

9. What does IL 2 do?
Not thymus - BM
Tetanus - Botulinum - HBV - Rabies
Activates cytotoxic CD 8 T cells as second signal
Its involved in inflammation and results in anaphylaxis and neutrophil chemotaxis.

10. What are the autoantibodies for polymyositis and dermatomyositis?
Anti Jo -1
Th1; interferon gamma; IL 2 for cytotoxic T cell activation
Both decrease cd8 tcell prolif but one through mtor and the other through calcineurin (resp)
Recurrent infections to every type of antigen; bone marrow transplant (be weary of GVH disease!)

11. In order to produce Antibodies - does the antigen have to be phagocytosed? give an example with a bug and an autoimmune (type II hypersensitivity for example).
Edema and necrosis in that region
Anti nuclear Antibodies (ANA); Anti dsDNA - anti Smith
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!
CRP - C3b - IgM

12. What do macrophages secrete that activate Th1 cells to secrete interferon gamma?
TNF alpha and IL1
pathogenesis
Not thymus - BM
P - ANCA (antimyeloperoxidase); in neutrophil; p= perinuclear

13. What is the mechanism for sirolimus? what else it known as?
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
Cell mediated due to T cell cytotoxicity reacting to foreign MHCs; few weeks after
Rheumatic arthritis
Immunosuppression after kidney transplantation

14. What are the main symptoms of B cell immunodeficiencies?
IL 1 - IL 6 - IL 12 - TNF alpha; IL 6- Th2 cells; IL 12- B cells
Internal iliac
SP infections
Its a serine protease that activates apoptosis; NK and CD8

15. What are the two signals required for Th1 cells? what happens after then activated?
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
AR; defect in MT function results in decreased transport and phagocytosis; recurrent pyogenic infections by staphylococci and streptococci - partial albinism - and peripheral neuropathy
MHC II/CD4 and B7 (on APC) and CD28 (on Th cell); releases cytokines to kill those extracellular buggers!
Antimicrobial also secreted by CD8 and NK cells that induces apoptsosis

16. ________ regulate the cell mediated response.
Humoral
Since cant cross placenta most likely means that child was forced early to produce due to an infection (most likely CMV)
encapsulated
IgM

17. which antibodies prevent antigens from binding mucosal surfaces?
Salmonella - 2 flagellar variants; Borrelia (relapsing fever); and Neisseria gonorrhoaea - pilus protein
Histamine (causes vasodilation) - leukotrienes (causes bronchoconstriction) - chemotaxins for eos - and heparin (increased blood flow needs to be anticoagulated!)
CD56
IgA

18. What is the most common selective Ig deficiency? What is the presentation?
An anaphylactic immediate reaction; atopy refers to the inherited propensity to develop asthmatic or allergic reactions
IgA; sinus and lung infections from lack of secretory defense - milk allergies and diarrhea from giardiasis; Anaphylasix on exposure to blood products with igA
...
SP infections

19. What is the presentation of hyperIgM syndrome?
Cyclosporine - OKT3
Severe pyogenic infections early in life
Thrombocytopenia
CD40 (on b cell) CD40 ligand on Th2 cell; and interleukins (4 -5 -6) from Th2 cell; CD40 is actually the second signal

20. What is the end result of complement activation? what bugs are this important for? through what pathway and why?
Thrombocytopenia
Anti glutamate carboxylase and anti insulin
not Ab mediated
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

21. What bugs can actually infect the lymph node itself?
Mycobacterium Tuberculosis - Mycobacterium Avium Intracellulare; Toxoplasmosis Gondii
Th cells fail to produce interferon gamma; a lot of IgE
Activate B cells - activate Macrophages - kill viruses directly - delayed cell mediated hypersensitivity - acute and chronic rejection
2 heavy chains and two light chains

22. The secondary follicles have __________; primary follicles are dense
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!
pale central germinal centers
Antidesmoglein
Liver! (they are proteins circulating in the blood)

23. In general What are T cells good for?
Immunosuppression after kidney transplantation
MHC I; from RER with help of the B2 microglobulin
IgM and IgG
Anti viral and anti tumor

24. What are superantigens? give two examples.
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
Opsonization (Brutons agammaglobulinemia) - adhesion (Leukocyte adhesion defect) - phagocytosis (chediak higashi syndrome) - respiratory burst (chronic granulomatous disease)
Coarse Faces - cold (noninflamed d/t inability to attract neutrophils) staph abscesses - retained primary teeth - high igE - dermatologic problems (eczema)
Defect in BTK a tyrosine kinase gene; failed maturation of B cells; X linked recessive

25. Monomer in circulation - ___ when secreted
Paracortex
dimer
Anti U1 RNP (ribonucleoprotein)
Activates Macrophages and Th1 cells; suppresses Th2 cells; antiviral and antitumor

26. What is the common variable immunodeficiency ? How is it different from Brutons?
Rheumatic arthritis
TCR - CD4/8 - CD28 (binds B7) - CD3 (for intracellular transduction) - CD40L
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
DM type I

27. What does interferon gamma do? What two type of cells does it attack mostly?
Stimulate the liver to release acute phase reactants
TLR ad nuclear receptors
Activates Macrophages and Th1 cells; suppresses Th2 cells; antiviral and antitumor
pale central germinal centers

28. Often bacteria are associated with being killed by humoral immunity. Name some bugs that require cell mediated immunity because they evade humoral response
Legionella - N. gonorrhea - L. monocytogenes - viruses - protozoa (leismaniasis)
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
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

29. What is the antimetabolite precursor of 6 mercaptopurine? What is the result?
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
...
Scratch test - histamine mediated wheal; radioimmunosorbent assay (detects specific IgEs in serum)
Carbohydrate

30. Which cytokines do Th2 release and For what?
Anticentromere; anti Scl -70 (anti DNA topoisomerase I)
Steroid responsive nephrotic syndrome
IL 4 -5 -6 for B cell class switching - IL 10 to inhibit TH1
Scratch test - histamine mediated wheal; radioimmunosorbent assay (detects specific IgEs in serum)

31. What does IL 10 do? who is secreted by?
Suppresses immune response (also specifically Th1 cells) and activates Th2; regulatory T cells
Anti smooth muscle
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
Remove encapsulated bacateria

32. How fast does it occur?
The patient could become cyanotic in the OR!
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
not Ab mediated
Anti topoisomerase

33. What are the autoantibodies for autoimmune hepatitis?
pale central germinal centers
Anti smooth muscle
TLR ad nuclear receptors
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

34. What are the three immune privileged sites? why are they called that? what happens after infection in these areas?
Opsonize bacteria (for enhanced phagocytosis) - neutralize viruses (igG) - activate complement (igM and igG) - sensitize mast cells (igE)
CD21 on B cells (although there is T cell lymphocytosis in EBV)
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
Kill them because they have CD16 on them that recognize the FcG portion

35. Which HLA's are included in MHC I? MHC II?

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36. Describe the capsular structure of a lymph node; What are the functions of the LN?
Yes
Hemochromatosis
Normal pro B (CD 19 +) - no mature B cells results in decreased total B cell level - and decreased amount of immunoglobulins in each class
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

37. The Fc region is found on the...
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
MS - hay fever - SLE - goodpastures
When you select for which MHC it will have; take out the lymphs that self react
carboxy terminal

38. The ______ in the BM are DN - the DP are in the cortex of thymus
Antidote for digoxin intoxication
T cell precursor
DM type I
Opsonization (Brutons agammaglobulinemia) - adhesion (Leukocyte adhesion defect) - phagocytosis (chediak higashi syndrome) - respiratory burst (chronic granulomatous disease)

39. What is oprelevkin? and What is it used for?
Glycoproteins; HLA
CD40 (on b cell) CD40 ligand on Th2 cell; and interleukins (4 -5 -6) from Th2 cell; CD40 is actually the second signal
Recom IL 11; thrombocytopenia
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 :(

40. What type of fenestrations are found in the red pulp of the spleen?
Complement activation (active in both)
Its involved in inflammation and results in anaphylaxis and neutrophil chemotaxis.
Fab portion
Barrel hoop basement membrane fenestrations

41. What is colostrum?
The igA found in breast milk
Viral neutralization of igM and IgG!
not Ab mediated
RNA segment reassortment

42. Type IV hypersensitivity is i...
Anti Ach receptor
Scratch test - histamine mediated wheal; radioimmunosorbent assay (detects specific IgEs in serum)
not Ab mediated
Opsonization (Brutons agammaglobulinemia) - adhesion (Leukocyte adhesion defect) - phagocytosis (chediak higashi syndrome) - respiratory burst (chronic granulomatous disease)

43. What is the pathogenesis of HyperIgE syndrome? What are the labs?
Leukocyte adhesion defect; ataxia telangietasia; ataxia telangiectasia; chediak higashi syndrome; IgA def; Digeorge syndrome; Jobs; Chediak Higashi
Th cells fail to produce interferon gamma; a lot of IgE
IL 4
Antimicrosomal and antithyroglobulin

44. which interleukin receptor is required for NK development? activation?
Influenza; antigenic shift; antigenic drift
IL 15; IL 12 - interferon Beta and interferon alpha
IgG
IgA; sinus and lung infections from lack of secretory defense - milk allergies and diarrhea from giardiasis; Anaphylasix on exposure to blood products with igA

45. How is the thymus organized? what happens in each section?
Stimulate the liver to release acute phase reactants
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
type four
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

46. What are the three types of APCs?
Macrophages - Dendritic cells - B cells
Paracortex
Decreased Th1 response; disseminated mycobacterial infections; decreased interferon gamma
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

47. What are the two signals required for B cell class switching? Which is the second signal?
Ischemia and necrosis of graft due to occlusion of vessels and fibrinoid necrosis and thrombosis within the vessels
CD40 (on b cell) CD40 ligand on Th2 cell; and interleukins (4 -5 -6) from Th2 cell; CD40 is actually the second signal
Make antibody - allergy type 1 (igE) - Cytotoxic and immunecomplex hypersensitivity type II and III (igG); hyperacute organ rejection is Ab mediated
Not thymus - BM

48. What are complements in the complement system? What activates them? there seems to be different ones - What are these pathways called?
Cells that stil have weird parts of their membrane that macrophages usually bite off
Immunosuppression after kidney transplantation in combination with cyclosporine and corticosteroids
IL 1 and IL 6
Proteins; IgG - IgM - endotoxin (microbial surfaces in general - nonspecific ones also) - mannose binding Lectin; classic - alternative - MB pathway (resp)

49. What is the main function of IL 12? other than macrophages who else can release IL 12?
Induce differentiation of T cells into Th1 helper cells and activates NK cells also; B cells
isotype
Histamine (causes vasodilation) - leukotrienes (causes bronchoconstriction) - chemotaxins for eos - and heparin (increased blood flow needs to be anticoagulated!)
C5a

50. where are complements produced?
CD56
Liver! (they are proteins circulating in the blood)
Axillary
Delayed type hypersensitivity