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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 Aldesleukin? What is it used for
Cross link
acute phase reactants
T cell precursor
A recomb cytokine of IL 2; RCC and metastatic melanoma

2. which B and T cell disorder presents with specifically low IgM?
HBV - HBC - Kaposis - leukemias - malignant melanoma - hairy cell leukemia and condyluma accuminata
Adenosine deaminase deficiency (AR) - defective IL 2 receptor (X linked) - and failure to synthesize MHC II; both humoral and cell mediated deficiency
Wiskott Aldrich syndrome
CD56

3. IgG...
Fever - urticaria - arthralgias - proteinuria - lymphadenopathy
opsonizes
cannot cross placenta
Paracortex; viral infection

4. What is an example of a parasite showing antigenic variation?
Acts as second signal on B cells to induce class switching to IgE and IgG
Activate B cells - activate Macrophages - kill viruses directly - delayed cell mediated hypersensitivity - acute and chronic rejection
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
Trypanosomes with programmed rearrangement (results in recurring fever -- sleeping sickness!)

5. What portion of the lymph node is not well developed in DiGeorge Syndrome?
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
Paracortex
Inferior mesenteric
pathogenesis

6. What is the antimetabolite precursor of 6 mercaptopurine? What is the result?
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
TCR - CD4/8 - CD28 (binds B7) - CD3 (for intracellular transduction) - CD40L
Paracortex
...

7. DTH (delayed type hypersensitivity) is the ________ of a PPD reaction
pathogenesis
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
Complement activation (active in both)
neutrophilia!

8. What are the major functions of Antibodies?
Histamine (causes vasodilation) - leukotrienes (causes bronchoconstriction) - chemotaxins for eos - and heparin (increased blood flow needs to be anticoagulated!)
Opsonize bacteria (for enhanced phagocytosis) - neutralize viruses (igG) - activate complement (igM and igG) - sensitize mast cells (igE)
Complement activation (active in both)
acute phase reactants

9. What is the toxicity of muromonab?
Cytokine release syndrome due to initial release from initial binding (fever etc) and hypersensitivity reaction
CRP - C3b - IgM
Anticentromere; anti Scl -70 (anti DNA topoisomerase I)
Glycoproteins; HLA

10. What is the presentation of scid? treatment?
Acts as second signal on B cells to induce class switching to IgE and IgG
CD56
Recurrent infections to every type of antigen; bone marrow transplant (be weary of GVH disease!)
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

11. What is the common variable immunodeficiency ? How is it different from Brutons?
Macrophages - Dendritic cells - B cells
In the germinal center of secondary follicles (In the paler center)
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
MHC I/CD8 and IL2/IL 2 Receptor (IL 2 is from Th1!); cytoxicity!

12. What does CD16 on NK cells do?
IgA
Superficial inguinal
Bind FcG for antibody dependent cellular cytotoxicity
Active; passive - fast but short half life (3 weeks!)

13. Type Iv hypersensitivity is...
Anti nuclear Antibodies (ANA); Anti dsDNA - anti Smith
delayed!
T
IL 15; IL 12 - interferon Beta and interferon alpha

14. What is the main cytokine released by T cells? What does it do
Surrounds the red pulp and begins with PALS and then turns into follicles with B cells/follicles
Previous transfusion; pregnant woman whose fetus had paternal antigens
mesenchymal
IL 3; supports growth and differentiation of bone marrow stem cells

15. What does interferon gamma do? What two type of cells does it attack mostly?
secondary
Its a serine protease that activates apoptosis; NK and CD8
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
Activates Macrophages and Th1 cells; suppresses Th2 cells; antiviral and antitumor

16. Complements are...
Yes
acute phase reactants
Negative nitroblue tetrazolium reduction test
Activates cytotoxic CD 8 T cells as second signal

17. What is recomb alpha interferon used for?
pale central germinal centers
Interferon gamma; Th1
HBV - HBC - Kaposis - leukemias - malignant melanoma - hairy cell leukemia and condyluma accuminata
Negative selection

18. What type of side chains are found on Fc region of an antibody?
Antigliadin - antiendomysial (both are IgAs - anti tissue transgluataminase igA)
Carbohydrate
Septicemia with neisseria; because at least you have C3 to act like a neutrophilic chemotactic and an acute phase reactant
IL 1 - IL 6 - IL 12 - TNF alpha; IL 6- Th2 cells; IL 12- B cells

19. What is the clinical use of Muromonab?
The place of T cell diff and maturation; ant mediastinum above heart; yes; 2
Paracortex; viral infection
Immunosuppression after kidney transplantation
Ig - CD19 - CD20 - CD21 - CD40 - MHC II - B7

20. 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
Influenza; antigenic shift; antigenic drift
Th2; Th1
Negative!

21. What part of the complement system also acts as an opsonin? What is opsonization? can you Name two other opsonins?
Influenza; antigenic shift; antigenic drift
Proteins; IgG - IgM - endotoxin (microbial surfaces in general - nonspecific ones also) - mannose binding Lectin; classic - alternative - MB pathway (resp)
Hereditary angioedema; PNH
C3b; coating of a pathogen with molecules that promotes phagocytosis; IgG and CRP

22. What are the autoantibodies for goodpastures syndrome?
Anti alpha subunit 3 of collagen on type IV bm
Both decrease cd8 tcell prolif but one through mtor and the other through calcineurin (resp)
IL 1 - IL 6 - IL 12 - TNF alpha; IL 6- Th2 cells; IL 12- B cells
Cross link

23. what ensure that a memory response is generated?
MHC class molecules bind to KIRS or CD94 to prevent killing
Salmonella - 2 flagellar variants; Borrelia (relapsing fever); and Neisseria gonorrhoaea - pilus protein
If there is class switching and plasma cell production (that is when memory cells are produced)
False! B cell class switching requires a second signal

24. What is an autograft? syngeneic graft? allograft? xenograft? What is an ex of an allograft? xenograft?
Edema and necrosis in that region
From self; from identical twin or clone; from nonidentical individual of same species; from different species; fetus; pig valve
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
A chemotactic factor for neutrophils

25. Which MHC presents intracellular peptides? how so?
encapsulated
MHC I; from RER with help of the B2 microglobulin
Local infection/inflammation; infection of the ln itself; metastasis
Anti SS- A (anti RO) and Anti SS- B

26. What are the autoantibodies for primary biliary cirrhosis?
Anti mitochondrial
Adenosine deaminase deficiency (AR) - defective IL 2 receptor (X linked) - and failure to synthesize MHC II; both humoral and cell mediated deficiency
In the germinal center of secondary follicles (In the paler center)
Histamine; post capillary venules - vasodilation

27. What is the difference of IgE AIHA and IgG AIHA if they are both complement dependent type II hypersensitivities?
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
MHC II - B7
Inferior mesenteric
Cross link antigens which increases their phagocytability; activate complement for MAC attack; opsonization; neutralization

28. where are complements produced?
Liver! (they are proteins circulating in the blood)
Anti Jo -1
Cyclosporine and tacrolimus; sirolimus (as well as hyperlipidemia)
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

29. Often bacteria are associated with being killed by humoral immunity. Name some bugs that require cell mediated immunity because they evade humoral response
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
Legionella - N. gonorrhea - L. monocytogenes - viruses - protozoa (leismaniasis)
Adenosine deaminase deficiency (AR) - defective IL 2 receptor (X linked) - and failure to synthesize MHC II; both humoral and cell mediated deficiency
MS

30. __________ are a part of the innate system.
Activates Th1 helper cells; Macrophages
Histamine; post capillary venules - vasodilation
Steroid responsive nephrotic syndrome
NK cells

31. What are the autoantibodies for wegeners granulomatosis?
Hyperacute; presence of preformed antibodies in the recipient ( to blood groups or HLA )
C - ANCA (antiproteinase); in neutrophil; c= cytoplasmic
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
Th cells fail to produce interferon gamma; a lot of IgE

32. What are some catalase positive organisms?
A - B - C; all the D's
TGF beta and IL 10
S. aureus - E. Coli - aspergillus
pathogenesis

33. What are the autoantibodies for polymyositis and dermatomyositis?
Anti U1 RNP (ribonucleoprotein)
A j chain
Anti Jo -1
Fever - urticaria - arthralgias - proteinuria - lymphadenopathy

34. What are MHC's necessary for? By themselves?
All MHC 1/CD8
T cell activation; no with CD 4 or CD 8
Graves
Leukocyte adhesion defect; ataxia telangietasia; ataxia telangiectasia; chediak higashi syndrome; IgA def; Digeorge syndrome; Jobs; Chediak Higashi

35. What does IL 2 do?
Immunoflourescent staining of tissue biopsies
MHC II - B7 - CD40 and CD14; CD40 and D14 for FcG and C3b resp
Activates cytotoxic CD 8 T cells as second signal
Previous transfusion; pregnant woman whose fetus had paternal antigens

36. What happens in a secondary follicle?
Isotype switching (activated by Th2 cell signals and cytokines) - somatic hypermutation
Tumor cells and virally infected cells; perforin pore to secrete granzymes through it; apoptosis
Since cant cross placenta most likely means that child was forced early to produce due to an infection (most likely CMV)
Superficial inguinal

37. What does it mean if there are igM in the serum at birth?
Interferon gamma; Th1
Antihistone
Since cant cross placenta most likely means that child was forced early to produce due to an infection (most likely CMV)
An alpha and beta chain; only on APCs; TCR and CD4; extracellular (phagocytosed by APCs)

38. What are the mediators that mast cells release?
Secretory component
The antibodies (igM or IgG) either neutralize the target directly (cytoxic!) or recruit leukocytes (Neutrophils and Macrophages!) to incite tissue damage
Histamine (causes vasodilation) - leukotrienes (causes bronchoconstriction) - chemotaxins for eos - and heparin (increased blood flow needs to be anticoagulated!)
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

39. 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
In the germinal center of secondary follicles (In the paler center)
neutrophilia!
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

40. What lymph node drains the testes?
Complement activation (active in both)
Cytokine release syndrome due to initial release from initial binding (fever etc) and hypersensitivity reaction
opsonizes
Para aortic

41. which antibodies prevent antigens from binding mucosal surfaces?
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
Anti IF
Type III hypersensitivity where an internal antigen antibody complexes activate classical complement pathway resulting in C3a neutrophilic chemotaxis and neutrophilic lysosomal death. SLE
IgA

42. can igG cross the placenta?
Lymphocytes
An alpha and beta chain; only on APCs; TCR and CD4; extracellular (phagocytosed by APCs)
Yes
Internal iliac

43. What are howell jolly bodies?
Cytokine release syndrome due to initial release from initial binding (fever etc) and hypersensitivity reaction
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 :(
Edema and necrosis in that region
Nuclear remnants that are usually taken out of RBC before complete maturation by Macrophages

44. What are the four steps in phagocytosis? What are the four disease that correspond to each step?
Active; passive - fast but short half life (3 weeks!)
Inferior mesenteric
Paracortex
Opsonization (Brutons agammaglobulinemia) - adhesion (Leukocyte adhesion defect) - phagocytosis (chediak higashi syndrome) - respiratory burst (chronic granulomatous disease)

45. What do macrophages secrete that activate Th1 cells to secrete interferon gamma?
Induce differentiation of T cells into Th1 helper cells and activates NK cells also; B cells
opsonizes
T cell activation; no with CD 4 or CD 8
TNF alpha and IL1

46. Which is the most abundant antibody in blood?
Anti TSh receptor
CD56
IgG
except hyperacute

47. Which disease is associated with HLA A3?
Immunosuppression after kidney transplantation in combination with cyclosporine and corticosteroids
Its involved in inflammation and results in anaphylaxis and neutrophil chemotaxis.
Hemochromatosis
Periarteriolar lymphatic sheath in the white pulp that surround that dead end of the capillaries in the red pulp - contain T cells

48. which antibodies can bind complement?
Yes
All MHC 1/CD8
IgM and IgG
IgA

49. Name two endogenous pyrogens
Septicemia with neisseria; because at least you have C3 to act like a neutrophilic chemotactic and an acute phase reactant
Alternative splicing of mRNA
IL 1 and IL 6
Activates Th1 helper cells; Macrophages

50. Monomer in circulation - ___ when secreted
Basophils! THey want IG E class switch!
active complement pathway
dimer
C5a

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