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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. Which disease is associated with B8?
IL 1 - IL 6 - IL 12 - TNF alpha; IL 6- Th2 cells; IL 12- B cells
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
Graves
IL 4 - 5 - 10 - 6

2. Which disease is associated with DR3?
Secretory component
DM type I
IgA
acute phase reactants

3. What are the main symptoms of T cell immunodeficiencies?
Intracellular pathogens (acute and chronic viruses and virally induced cancers)
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
Surrounds the red pulp and begins with PALS and then turns into follicles with B cells/follicles
Rheumatic arthritis

4. What do mature naive B lymphocytes express?
CRP - C3b - IgM
IgM and IgD
pentamer
Ischemia and necrosis of graft due to occlusion of vessels and fibrinoid necrosis and thrombosis within the vessels

5. What is the receptor for EBV? On what cells is that located?
CD21 on B cells (although there is T cell lymphocytosis in EBV)
...
MHC II - B7
Fab portion

6. which type of immunity is slow but long lasting? as opposed to...
Superficial inguinal
CD40 (on b cell) CD40 ligand on Th2 cell; and interleukins (4 -5 -6) from Th2 cell; CD40 is actually the second signal
Active; passive - fast but short half life (3 weeks!)
Activates cytotoxic CD 8 T cells as second signal

7. What is the late phase reaction of anaphylaxis allergy? what mediates it?
IgG
Inferior mesenteric
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)
Make antibody - allergy type 1 (igE) - Cytotoxic and immunecomplex hypersensitivity type II and III (igG); hyperacute organ rejection is Ab mediated

8. which interleukin receptor is required for NK development? activation?
In the germinal center of secondary follicles (In the paler center)
Antigliadin - antiendomysial (both are IgAs - anti tissue transgluataminase igA)
IL 15; IL 12 - interferon Beta and interferon alpha
C5a

9. A lymph node is a ________ lymphoid organ.
Previous transfusion; pregnant woman whose fetus had paternal antigens
secondary
IgM and IgA
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

10. which of the transplant rejections is antibody mediated? why does it occur?
MHC I; from RER with help of the B2 microglobulin
Adaptive uses classic pathway to kill; innate uses alternative pathway to kill
Both decrease cd8 tcell prolif but one through mtor and the other through calcineurin (resp)
Hyperacute; presence of preformed antibodies in the recipient ( to blood groups or HLA )

11. The MALT/GALT are not...
Surrounds the red pulp and begins with PALS and then turns into follicles with B cells/follicles
Secretory component
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
encapsulated

12. 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
Induce differentiation of T cells into Th1 helper cells and activates NK cells also; B cells
TNF alpha and IL1
Adaptive uses classic pathway to kill; innate uses alternative pathway to kill

13. where do NK cells develop?
T
pale central germinal centers
Not thymus - BM
Increases expression of MHC I and MHC II and also activates NK cells

14. The pathogenesis of contact dermatitis is ________ hypersensitivity
type four
IL 4 - 5 - 10 - 6
Anti alpha subunit 3 of collagen on type IV bm
Edema and necrosis in that region

15. What is the defect in hyper IgM syndrome? What are the lab results?
Secretory component
False! B cell class switching requires a second signal
Defect in CD40L results in inability to class switch; a lot of IgM and no IgG - A - E
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

16. IgM can exist as a _______ also
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
Make antibody - allergy type 1 (igE) - Cytotoxic and immunecomplex hypersensitivity type II and III (igG); hyperacute organ rejection is Ab mediated
pentamer
Tetanus - Botulinum - HBV - Rabies

17. what happens in a deficiency of C1 esterase inhibitor? DAF?
...
T cell precursor
Hereditary angioedema; PNH
IL 4 - 5 - 10 - 6

18. What is the toxicity of muromonab?
Surrounds the red pulp and begins with PALS and then turns into follicles with B cells/follicles
Cytokine release syndrome due to initial release from initial binding (fever etc) and hypersensitivity reaction
An anaphylactic immediate reaction; atopy refers to the inherited propensity to develop asthmatic or allergic reactions
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

19. What are the autoantibodies for autoimmune hepatitis?
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
Anti smooth muscle
Popliteal
Hyperacute; presence of preformed antibodies in the recipient ( to blood groups or HLA )

20. What happens in a secondary follicle?
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
B - T - and NK cells
Antidesmoglein
Isotype switching (activated by Th2 cell signals and cytokines) - somatic hypermutation

21. What are the two signals to kill for NK cells?
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
Septicemia with neisseria; because at least you have C3 to act like a neutrophilic chemotactic and an acute phase reactant
Proteins; IgG - IgM - endotoxin (microbial surfaces in general - nonspecific ones also) - mannose binding Lectin; classic - alternative - MB pathway (resp)
Lack of MHC class I constant region which it binds or a nonspecific activation signal (TLR)

22. What type of fenestrations are found in the red pulp of the spleen?
TCR - CD4/8 - CD28 (binds B7) - CD3 (for intracellular transduction) - CD40L
Anemias (esp due to renal failure)
Barrel hoop basement membrane fenestrations
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 :(

23. The secondary follicles have __________; primary follicles are dense
MHC class molecules bind to KIRS or CD94 to prevent killing
pale central germinal centers
Acts as second signal on B cells to induce class switching to IgA; also stimulates eosinophils
mesenchymal

24. What does granulysin do?
Antimicrobial also secreted by CD8 and NK cells that induces apoptsosis
The igA found in breast milk
IL 5
type four

25. What is filgrastim and sargramostim? and What is it used for?
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!
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
Recomb cytokine of GCSF (granulocyte macrophage colony stimulating factor; for recovery of bone marrow
Fever - urticaria - arthralgias - proteinuria - lymphadenopathy

26. The two heavy chains of an antibody contribute to the...
Fab portion
IgM
IL 3; supports growth and differentiation of bone marrow stem cells
Antidesmoglein

27. How does the alternative pathway lead to MAC activation?
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
Cell mediated due to T cell cytotoxicity reacting to foreign MHCs; few weeks after
HBV - HBC - Kaposis - leukemias - malignant melanoma - hairy cell leukemia and condyluma accuminata
MHC II/CD4 and B7 (on APC) and CD28 (on Th cell); releases cytokines to kill those extracellular buggers!

28. Which antibodies can be multimeric?
T cell activation; no with CD 4 or CD 8
IgM and IgA
Yes
Its a serine protease that activates apoptosis; NK and CD8

29. What is the presentation of Brutons agammaglobulinemia?
Patient has had previous exposure to blood products which result in presence of preformed anti HLA cytotoxic Abs
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
An anaphylactic immediate reaction; atopy refers to the inherited propensity to develop asthmatic or allergic reactions
Recurrent sinopulmonary bacterial infections after 6 months (d/t mothers igGs transplacental) due to opsonization defect

30. What is MHC I made out of? Where is it found? What does it bind to? What type of antigens does it present?
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
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
Secretory component
An alpha chain and a B2 microglobulin; on all nucleated cells; TCR and CD8; intracellular antigens

31. What is the pathology of acute transplant rejection? is it reversible?
Hyperacute; presence of preformed antibodies in the recipient ( to blood groups or HLA )
DM type I and RA
Recurrent infections to every type of antigen; bone marrow transplant (be weary of GVH disease!)
Vasculitis of graft vessels with dense interstitial lymphocytic infiltrate; yes! with immunosuppressants

32. What are the main Cell surface proteins on T cells?
Viral neutralization of igM and IgG!
Hereditary angioedema; PNH
TCR - CD4/8 - CD28 (binds B7) - CD3 (for intracellular transduction) - CD40L
IgM

33. What are the mediators that mast cells release?
Histamine (causes vasodilation) - leukotrienes (causes bronchoconstriction) - chemotaxins for eos - and heparin (increased blood flow needs to be anticoagulated!)
Paracortex
Lymphocytes
Adenosine deaminase deficiency (AR) - defective IL 2 receptor (X linked) - and failure to synthesize MHC II; both humoral and cell mediated deficiency

34. What is the general structure of an Ab?
Intracellular pathogens (acute and chronic viruses and virally induced cancers)
Lack of MHC class I constant region which it binds or a nonspecific activation signal (TLR)
2 heavy chains and two light chains
Anti SS- A (anti RO) and Anti SS- B

35. Which Thelper cell activated Macrophages? by secreting what? what else does Th1 secrete? For what?
Tumor cells and virally infected cells; perforin pore to secrete granzymes through it; apoptosis
Th1; interferon gamma; IL 2 for cytotoxic T cell activation
CD56
Since cant cross placenta most likely means that child was forced early to produce due to an infection (most likely CMV)

36. other than C3a - what other complement acts as an anaphyloxin?
C5a
Defect in CD40L results in inability to class switch; a lot of IgM and no IgG - A - E
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
Anti topoisomerase

37. What is the mechanism for sirolimus? what else it known as?
Vasculitis of graft vessels with dense interstitial lymphocytic infiltrate; yes! with immunosuppressants
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
MHC II/CD4 and B7 (on APC) and CD28 (on Th cell); releases cytokines to kill those extracellular buggers!
Paracortex; viral infection

38. What is the pathogenesis of a hypersensitivity reaction?
Fc
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
Not thymus - BM
Salmonella - 2 flagellar variants; Borrelia (relapsing fever); and Neisseria gonorrhoaea - pilus protein

39. Monomer in circulation - ___ when secreted
Mediates septic shock; activates the endothelium for adhesion and dilation and leukocyte recruitment results in vascular leak
dimer
Th1; interferon gamma; IL 2 for cytotoxic T cell activation
Receiving preformed Antibodies

40. For which toxins are preformed antibodies (passive) given?
Tetanus - Botulinum - HBV - Rabies
Axillary
Glycoproteins; HLA
Increases expression of MHC I and MHC II and also activates NK cells

41. Which diseases are associated with DR5?
Pernicious Anemia and Hashimotos
IL 15; IL 12 - interferon Beta and interferon alpha
IL 4
Influenza; antigenic shift; antigenic drift

42. What does Interferon alpha and beta do? how?
Fever - urticaria - arthralgias - proteinuria - lymphadenopathy
IgA; sinus and lung infections from lack of secretory defense - milk allergies and diarrhea from giardiasis; Anaphylasix on exposure to blood products with igA
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
Antiviral by inducing ribonuclease which degrades only viral mRNA (prevents protein synthesis) and activates NK cells to kill virus infected cells

43. What is the common variable immunodeficiency ? How is it different from Brutons?
Nuclear remnants that are usually taken out of RBC before complete maturation by Macrophages
Interferon gamma and IL 2
Liver! (they are proteins circulating in the blood)
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

44. What lymph node drains the testes?
RNA segment reassortment
Antidesmoglein
Anti mitochondrial
Para aortic

45. What is passive immunity?
Isotype switching (activated by Th2 cell signals and cytokines) - somatic hypermutation
Recurrent infections to every type of antigen; bone marrow transplant (be weary of GVH disease!)
Adaptive uses classic pathway to kill; innate uses alternative pathway to kill
Receiving preformed Antibodies

46. What is colostrum?
IgG
Cyclosporine - OKT3
The igA found in breast milk
Defect in CD40L results in inability to class switch; a lot of IgM and no IgG - A - E

47. How do you test for type III hypersensitivity?
Induces fever - chemokine secretion to recruit - activates adhesion molecules; macrophages
Barrel hoop basement membrane fenestrations
Immunoflourescent staining of tissue biopsies
Cytokine release syndrome due to initial release from initial binding (fever etc) and hypersensitivity reaction

48. Complements are...
Hyperacute; presence of preformed antibodies in the recipient ( to blood groups or HLA )
acute phase reactants
IL 4 - 5 - 10 - 6
IL 4 -5 -6 for B cell class switching - IL 10 to inhibit TH1

49. What are some sinopulmonary infections?
Surrounds the red pulp and begins with PALS and then turns into follicles with B cells/follicles
Sinusitis - otitis media - pneumonia
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
Superficial inguinal

50. Name two endogenous pyrogens
CRP - C3b - IgM
Fibrosis of blood vessels and graft tissue from ischemia; obliterative vascular fibrosis with intimal thickening
IL 1 and IL 6
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