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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. The MALT/GALT are not...
lowest concentration
Graves
encapsulated
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

2. What do macrophages secrete that activate Th1 cells to secrete interferon gamma?
Tetanus - Botulinum - HBV - Rabies
TNF alpha and IL1
When you select for which MHC it will have; take out the lymphs that self react
IgG

3. what will NK cells do to cells covered in IgG Ab? why?
MHC I/CD8 and IL2/IL 2 Receptor (IL 2 is from Th1!); cytoxicity!
MS
Kill them because they have CD16 on them that recognize the FcG portion
Th cells fail to produce interferon gamma; a lot of IgE

4. hat is the presentation of Jobs syndrome or Hyper IgE?
Coarse Faces - cold (noninflamed d/t inability to attract neutrophils) staph abscesses - retained primary teeth - high igE - dermatologic problems (eczema)
IgA; sinus and lung infections from lack of secretory defense - milk allergies and diarrhea from giardiasis; Anaphylasix on exposure to blood products with igA
Mycobacterium Tuberculosis - Mycobacterium Avium Intracellulare; Toxoplasmosis Gondii
delayed!

5. What is the result of an IL 12 deficiency? What is the presentation? What are the labs?
Axillary
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
Histamine; post capillary venules - vasodilation
Decreased Th1 response; disseminated mycobacterial infections; decreased interferon gamma

6. Which disease is associated withB B27?
Some microbial surfaces (only) have mannan binding lectin which activates a protease that cleaves C2 and C4 which combine to make C3. the rest follows the alternative pathway
P - ANCA (antimyeloperoxidase); in neutrophil; p= perinuclear
Psoriasis - Ankylosis Spondylitis - IBD - Reiters; all seronegative spondylopathies
Glycoproteins; HLA

7. What is the receptor for EBV? On what cells is that located?
CD21 on B cells (although there is T cell lymphocytosis in EBV)
Anti viral and anti tumor
T
Immunosuppression after kidney transplantation

8. What are the autoantibodies for hashimotos?
Antimicrosomal and antithyroglobulin
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
Antigliadin - antiendomysial (both are IgAs - anti tissue transgluataminase igA)
Paracortex; viral infection

9. what cell surface marker is used for NK cells as it is unique to them?
pathogenesis
Defect in CD40L results in inability to class switch; a lot of IgM and no IgG - A - E
CD56
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

10. DTH (delayed type hypersensitivity) is the ________ of a PPD reaction
Local infection/inflammation; infection of the ln itself; metastasis
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
pathogenesis
isotype

11. What are superantigens? give two examples.
Bind FcG for antibody dependent cellular cytotoxicity
Psoriasis - Ankylosis Spondylitis - IBD - Reiters; all seronegative spondylopathies
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
Ig - CD19 - CD20 - CD21 - CD40 - MHC II - B7

12. What does IL 10 do? who is secreted by?
Suppresses immune response (also specifically Th1 cells) and activates Th2; regulatory T cells
Negative nitroblue tetrazolium reduction test
Graves
Superficial inguinal

13. What is the most common selective Ig deficiency? What is the presentation?
IgA; sinus and lung infections from lack of secretory defense - milk allergies and diarrhea from giardiasis; Anaphylasix on exposure to blood products with igA
Ig - CD19 - CD20 - CD21 - CD40 - MHC II - B7
Antidesmoglein
Fab portion

14. what results in symptoms of shock in an acute hemolytic transfusion reaction?
Since it is a comp dependent type II hypersensitivity reaction; C3a brings anaphylotoxins that bring in mediators of shock
IL 4
Edema and necrosis in that region
T cell precursor

15. The Fc region is found on the...
secondary
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
carboxy terminal
Axillary

16. which B and T cell disorder presents with specifically low IgM?
Wiskott Aldrich syndrome
Immune complex - Arthus reaction and Serum sickness; they are all a result of antibody- antigen complex deposition resulting in complement activation
Axillary
carboxy terminal

17. 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
Periarteriolar lymphatic sheath in the white pulp that surround that dead end of the capillaries in the red pulp - contain T cells
Liver! (they are proteins circulating in the blood)
Antimicrobial also secreted by CD8 and NK cells that induces apoptsosis

18. __________ are a part of the innate system.
Celiac
NK cells
Mycobacterium Tuberculosis - Mycobacterium Avium Intracellulare; Toxoplasmosis Gondii
An alpha chain and a B2 microglobulin; on all nucleated cells; TCR and CD8; intracellular antigens

19. Which diseases are associated with DR4?
Patient has had previous exposure to blood products which result in presence of preformed anti HLA cytotoxic Abs
DM type I and RA
Barrel hoop basement membrane fenestrations
Coarse Faces - cold (noninflamed d/t inability to attract neutrophils) staph abscesses - retained primary teeth - high igE - dermatologic problems (eczema)

20. What cytokines to Th2 secrete?
Defect in CD40L results in inability to class switch; a lot of IgM and no IgG - A - E
IgG
Alternative splicing of mRNA
IL 4 - 5 - 10 - 6

21. What does it mean if there are igM in the serum at birth?
Since cant cross placenta most likely means that child was forced early to produce due to an infection (most likely CMV)
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
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
mesenchymal

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

23. Which antibodies can be multimeric?
Cytokine IL 10 secreted by Th2
All MHC 1/CD8
IgM and IgA
Cyclosporine - OKT3

24. Which is the main antibody that provides passive immunity to infants?
Interferon gamma; Th1
active complement pathway
IgG
Immune complex - Arthus reaction and Serum sickness; they are all a result of antibody- antigen complex deposition resulting in complement activation

25. IgE has the ___________ in the serum
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 :(
lowest concentration
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
Carbohydrate

26. The idiotype; the Fc portion determines the...
isotype
T cell activation; no with CD 4 or CD 8
No because no peptide fragment!
secondary

27. What type of cells do NK cells attack? with What tools? by necrosis or apoptosis?
Cross link antigens which increases their phagocytability; activate complement for MAC attack; opsonization; neutralization
MHC I; from RER with help of the B2 microglobulin
Tumor cells and virally infected cells; perforin pore to secrete granzymes through it; apoptosis
Tetanus - Botulinum - HBV - Rabies

28. What are the three types of Type III hypersensitivity ? What is the common mechanism between them?
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
Immune complex - Arthus reaction and Serum sickness; they are all a result of antibody- antigen complex deposition resulting in complement activation
Severe recurrent pyogenic sinus and resp tract And increased susceptibility to type III hypersensitivity like SLE
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. Which cytokines do Th2 release and For what?
IL 4 -5 -6 for B cell class switching - IL 10 to inhibit TH1
opsonizes
IgM and IgA
Fab portion

30. What are the autoantibodies for other vasculitides?
Adenosine deaminase deficiency (AR) - defective IL 2 receptor (X linked) - and failure to synthesize MHC II; both humoral and cell mediated deficiency
Fc
P - ANCA (antimyeloperoxidase); in neutrophil; p= perinuclear
IgG and IgM bind to pathogens activating C1 convertase and leads to C2 and C4 and then C3 convertase activated

31. How is i Th1 helper cell inhibited?
Antimicrobial also secreted by CD8 and NK cells that induces apoptsosis
Active; passive - fast but short half life (3 weeks!)
IL 4 -5 -6 for B cell class switching - IL 10 to inhibit TH1
Cytokine IL 10 secreted by Th2

32. 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
Increases expression of MHC I and MHC II and also activates NK cells
IgM and IgD
Pernicious Anemia and Hashimotos

33. What are howell jolly bodies?
Nuclear remnants that are usually taken out of RBC before complete maturation by Macrophages
DM type I
Yes
MS - hay fever - SLE - goodpastures

34. What does Interferon alpha and beta do? how?
lowest concentration
Tetanus - Botulinum - HBV - Rabies
Popliteal
Antiviral by inducing ribonuclease which degrades only viral mRNA (prevents protein synthesis) and activates NK cells to kill virus infected cells

35. What is the main function of IL 8?
A chemotactic factor for neutrophils
Pernicious Anemia and Hashimotos
Edema and necrosis in that region
Activates cytotoxic CD 8 T cells as second signal

36. What are the autoantibodies for primary biliary cirrhosis?
Anti mitochondrial
Leukocyte adhesion defect; ataxia telangietasia; ataxia telangiectasia; chediak higashi syndrome; IgA def; Digeorge syndrome; Jobs; Chediak Higashi
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
A B and T cell disorder; defect in DNA repair enzymes; ataxia - telangactasia and IgA def; igA def. and increased AFP

37. What lymph node drains the stomach?
Th2; Th1
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
A j chain
Celiac

38. 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)?
IL 4 - 5 - 10 - 6
DAF and C1 esterase inhibitor on cells prevent complement activation on their surfaces (microbial surfaces lack this)
...
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

39. What bugs can actually infect the lymph node itself?
Defect in CD40L results in inability to class switch; a lot of IgM and no IgG - A - E
Since it is a comp dependent type II hypersensitivity reaction; C3a brings anaphylotoxins that bring in mediators of shock
Mycobacterium Tuberculosis - Mycobacterium Avium Intracellulare; Toxoplasmosis Gondii
Wiskott Aldrich syndrome

40. What lymph node drains the lateral side of the dorsum of the foot?
Activate macrophages
Popliteal
dimer
Activate B cells - activate Macrophages - kill viruses directly - delayed cell mediated hypersensitivity - acute and chronic rejection

41. How is sirolimus different from tacrolimus?
Severe recurrent pyogenic sinus and resp tract And increased susceptibility to type III hypersensitivity like SLE
opsonizes
Both decrease cd8 tcell prolif but one through mtor and the other through calcineurin (resp)
Paracortex; viral infection

42. How does complement link innate and adaptive?
Adaptive uses classic pathway to kill; innate uses alternative pathway to kill
DM type I and RA
Cytokine IL 10 secreted by Th2
The igA found in breast milk

43. What are the symptoms of serum sickness?
Fever - urticaria - arthralgias - proteinuria - lymphadenopathy
Patient has had previous exposure to blood products which result in presence of preformed anti HLA cytotoxic Abs
TGF beta and IL 10
Anti TSh receptor

44. What is three common causes of severe combined immunodef? What is the result of all three?
carboxy terminal
Adenosine deaminase deficiency (AR) - defective IL 2 receptor (X linked) - and failure to synthesize MHC II; both humoral and cell mediated deficiency
Steroid responsive nephrotic syndrome
The antibodies (igM or IgG) either neutralize the target directly (cytoxic!) or recruit leukocytes (Neutrophils and Macrophages!) to incite tissue damage

45. The ______ in the BM are DN - the DP are in the cortex of thymus
pathogenesis
A - B - C; all the D's
T cell precursor
Anti U1 RNP (ribonucleoprotein)

46. Name three things that IL 1 does as a cytokine. other than the liver - who secretes IL 1
Patient has had previous exposure to blood products which result in presence of preformed anti HLA cytotoxic Abs
If there is class switching and plasma cell production (that is when memory cells are produced)
Induces fever - chemokine secretion to recruit - activates adhesion molecules; macrophages
Defect in CD40L results in inability to class switch; a lot of IgM and no IgG - A - E

47. Give three examples of bacteria that use antigenic variation and how.
Salmonella - 2 flagellar variants; Borrelia (relapsing fever); and Neisseria gonorrhoaea - pilus protein
Activate macrophages
Anti SS- A (anti RO) and Anti SS- B
IL 3; supports growth and differentiation of bone marrow stem cells

48. What are some sinopulmonary infections?
delayed!
Interferon gamma and IL 2
IgG
Sinusitis - otitis media - pneumonia

49. which of the IL2 inhibitors produce nephrotoxicity? thrombocytopenia/leukopenia?
Superficial inguinal
pale central germinal centers
Cyclosporine and tacrolimus; sirolimus (as well as hyperlipidemia)
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

50. are Th cells involved in trapping of antigens of endotoxin/LPS?
IL 4 - 5 - 10 - 6
T cell dysfunction
No because no peptide fragment!
Patient has had previous exposure to blood products which result in presence of preformed anti HLA cytotoxic Abs