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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. What is a factor that is a predictor for a bad transplantation?
MHC I/CD8 and IL2/IL 2 Receptor (IL 2 is from Th1!); cytoxicity!
Patient has had previous exposure to blood products which result in presence of preformed anti HLA cytotoxic Abs
not Ab mediated
pentamer

2. What does granulysin do?
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
Cell mediated due to T cell cytotoxicity reacting to foreign MHCs; few weeks after
Antimicrobial also secreted by CD8 and NK cells that induces apoptsosis
Patient has had previous exposure to blood products which result in presence of preformed anti HLA cytotoxic Abs

3. What amine is the main chemical mediator released by mast cells? Where does it act What does it result in?
T
Histamine; post capillary venules - vasodilation
Antimicrobial also secreted by CD8 and NK cells that induces apoptsosis
Both decrease cd8 tcell prolif but one through mtor and the other through calcineurin (resp)

4. which antibody activate mast cells - basophils - and eosinophils?
Anticentromere; anti Scl -70 (anti DNA topoisomerase I)
IgE
neutrophilia!
Th cells fail to produce interferon gamma; a lot of IgE

5. T/F B cells do not require a second signal
Paracortex; viral infection
Opsonization (Brutons agammaglobulinemia) - adhesion (Leukocyte adhesion defect) - phagocytosis (chediak higashi syndrome) - respiratory burst (chronic granulomatous disease)
When you select for which MHC it will have; take out the lymphs that self react
False! B cell class switching requires a second signal

6. What are the autoantibodies for systemic sclerosis?
Anti topoisomerase
Its main effect is a defect in Ab opsonization for killing
Superficial inguinal
MHC II - B7 - CD40 and CD14; CD40 and D14 for FcG and C3b resp

7. What two ways do you test for a type 1 hypersensitivity reaction? what will you see?
Severe pyogenic infections early in life
Recomb cytokine of GCSF (granulocyte macrophage colony stimulating factor; for recovery of bone marrow
Ig - CD19 - CD20 - CD21 - CD40 - MHC II - B7
Scratch test - histamine mediated wheal; radioimmunosorbent assay (detects specific IgEs in serum)

8. Name three things that IL 1 does as a cytokine. other than the liver - who secretes IL 1
Induces fever - chemokine secretion to recruit - activates adhesion molecules; macrophages
In any situation where immunologically competent cells are transplanted into immunologically crippled recipient; graft rejects all the cells due to foreign proteins resulting in severe organ dysfunction
IgA; sinus and lung infections from lack of secretory defense - milk allergies and diarrhea from giardiasis; Anaphylasix on exposure to blood products with igA
In the germinal center of secondary follicles (In the paler center)

9. What is recomb beta interferon used for?
An anaphylactic immediate reaction; atopy refers to the inherited propensity to develop asthmatic or allergic reactions
IL 15; IL 12 - interferon Beta and interferon alpha
Monoclonal Ab to CD3- blocks cellular transduction and signaling of T cells
MS

10. What is the presentation of common variable immunodef? and What are the labs?
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
MHC class molecules bind to KIRS or CD94 to prevent killing
Normal pro B (CD 19 +) - no mature B cells results in decreased total B cell level - and decreased amount of immunoglobulins in each class
Barrel hoop basement membrane fenestrations

11. Monomer in circulation - ___ when secreted
Anti U1 RNP (ribonucleoprotein)
Antihistone
dimer
not Ab mediated

12. What does IL 2 do?
Fc
Activates cytotoxic CD 8 T cells as second signal
Steroid responsive nephrotic syndrome
All MHC 1/CD8

13. What are the autoantibodies for pernicious anemia?
Not thymus - BM
Antidesmoglein
Immunosuppression after kidney transplantation in combination with cyclosporine and corticosteroids
Anti IF

14. To what portion of the Antibody do the complements bind?
Fc
Both decrease cd8 tcell prolif but one through mtor and the other through calcineurin (resp)
C - ANCA (antiproteinase); in neutrophil; c= cytoplasmic
isotype

15. What lymph node drains the anal canal (below the pectinate line)?
Histamine; post capillary venules - vasodilation
MHC I - CD16 - CD56
Both decrease cd8 tcell prolif but one through mtor and the other through calcineurin (resp)
Superficial inguinal

16. other than mediating shock - what else does TNF alpha do? who releases it mainly?
TNF alpha and IL1
...
MHC I/CD8 and IL2/IL 2 Receptor (IL 2 is from Th1!); cytoxicity!
Activates Th1 helper cells; Macrophages

17. What are the three types of Type III hypersensitivity ? What is the common mechanism between them?
Macrophages - Dendritic cells - B cells
Immune complex - Arthus reaction and Serum sickness; they are all a result of antibody- antigen complex deposition resulting in complement activation
Mycobacterium Tuberculosis - Mycobacterium Avium Intracellulare; Toxoplasmosis Gondii
Internal iliac

18. What are four results of a splenectomy?
An antigen encounter (presented by APC for Th2) with Th2 will result in it to go to the cortical section and help with B cell activation; Cytotoxic T cell will enter vasculature/efferent lymph to go kill; B cell will wait for Th2 for activation and t
MHC I; from RER with help of the B2 microglobulin
1) susceptibility to encapsulated organisms 2) Howell Jolly Bodies 3) Target cells 4) Thrombocytosis
Isotype switching (activated by Th2 cell signals and cytokines) - somatic hypermutation

19. How do we use thymus dependent antigens to prevent infection from organisms that lack a peptide component?
Ig - CD19 - CD20 - CD21 - CD40 - MHC II - B7
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
delayed!
An alpha and beta chain; only on APCs; TCR and CD4; extracellular (phagocytosed by APCs)

20. What lymph node drains the testes?
Para aortic
heavy chains
Scratch test - histamine mediated wheal; radioimmunosorbent assay (detects specific IgEs in serum)
type four

21. What lymph node drains the duodenum - jejunum?
Superior mesenteric
It is a localized type III hypersensitivity reaction to an external antigen; localized instead of systemic; ?; intradermal injection of the antigen results in antibody production and antigen antibody complexes deposit in the skin
S. aureus - E. Coli - aspergillus
pale central germinal centers

22. What does IL 4 do?
RNA segment reassortment
DM type I
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
Acts as second signal on B cells to induce class switching to IgE and IgG

23. where do NK cells develop?
Anti alpha subunit 3 of collagen on type IV bm
An antigen encounter (presented by APC for Th2) with Th2 will result in it to go to the cortical section and help with B cell activation; Cytotoxic T cell will enter vasculature/efferent lymph to go kill; B cell will wait for Th2 for activation and t
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
Not thymus - BM

24. Which disease is associated withB B27?
Alternative splicing of mRNA
Psoriasis - Ankylosis Spondylitis - IBD - Reiters; all seronegative spondylopathies
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
Recurrent sinopulmonary bacterial infections after 6 months (d/t mothers igGs transplacental) due to opsonization defect

25. What does Interferon alpha and beta do? how?
IL 15; IL 12 - interferon Beta and interferon alpha
CD21 on B cells (although there is T cell lymphocytosis in EBV)
Anti smooth muscle
Antiviral by inducing ribonuclease which degrades only viral mRNA (prevents protein synthesis) and activates NK cells to kill virus infected cells

26. What lymph node drains the lateral side of the dorsum of the foot?
Interferon gamma and IL 2
T cell dysfunction
Popliteal
Receiving preformed Antibodies

27. 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?
No because no peptide fragment!
Immunosuppression after kidney transplantation
Leukocyte adhesion defect; ataxia telangietasia; ataxia telangiectasia; chediak higashi syndrome; IgA def; Digeorge syndrome; Jobs; Chediak Higashi
isotype

28. Complements are...
Secretory component
acute phase reactants
MHC I; from RER with help of the B2 microglobulin
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

29. The two heavy chains of an antibody contribute to the...
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
CD21 on B cells (although there is T cell lymphocytosis in EBV)
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 :(
Fab portion

30. What are the autoantibodies for Mixed connective tissue disease?
All MHC 1/CD8
An alpha chain and a B2 microglobulin; on all nucleated cells; TCR and CD8; intracellular antigens
Anti U1 RNP (ribonucleoprotein)
Immunoflourescent staining of tissue biopsies

31. What is serum sickness? give an example.
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
Isotype switching (activated by Th2 cell signals and cytokines) - somatic hypermutation
A B and T cell disorder; defect in DNA repair enzymes; ataxia - telangactasia and IgA def; igA def. and increased AFP
Recom IL 11; thrombocytopenia

32. What cytokines are released by Th1 cells?
T
IgG
Interferon gamma and IL 2
A chemotactic factor for neutrophils

33. What is the pathogenesis of a candida skin test?
MHC II - B7 - CD40 and CD14; CD40 and D14 for FcG and C3b resp
Delayed type hypersensitivity
An acidified endosome with the antigen fuses with the MHC which causes the release of the invariant chain Which is sitting in spot of antigen and stabilizing the MHC II
IgA; sinus and lung infections from lack of secretory defense - milk allergies and diarrhea from giardiasis; Anaphylasix on exposure to blood products with igA

34. What is the pathogenesis of a hypersensitivity reaction?
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
...
MS - hay fever - SLE - goodpastures
Anti topoisomerase

35. Leukocyte adhesion defect presents with...
An anaphylactic immediate reaction; atopy refers to the inherited propensity to develop asthmatic or allergic reactions
No because no peptide fragment!
neutrophilia!
Fibrosis of blood vessels and graft tissue from ischemia; obliterative vascular fibrosis with intimal thickening

36. which of the IL2 inhibitors produce nephrotoxicity? thrombocytopenia/leukopenia?
RNA segment reassortment
Anticentromere; anti Scl -70 (anti DNA topoisomerase I)
Cyclosporine and tacrolimus; sirolimus (as well as hyperlipidemia)
T cells react to the angtigen and activate leukocyted (macrophage acitivation)

37. What is the receptor for EBV? On what cells is that located?
Severe recurrent pyogenic sinus and resp tract And increased susceptibility to type III hypersensitivity like SLE
CD21 on B cells (although there is T cell lymphocytosis in EBV)
Anti alpha subunit 3 of collagen on type IV bm
Mycobacterium Tuberculosis - Mycobacterium Avium Intracellulare; Toxoplasmosis Gondii

38. What cytokines do macrophages release? who else can secrete IL 6? IL 12?
IL 1 - IL 6 - IL 12 - TNF alpha; IL 6- Th2 cells; IL 12- B cells
Fever - urticaria - arthralgias - proteinuria - lymphadenopathy
Kill them because they have CD16 on them that recognize the FcG portion
Intracellular pathogens (acute and chronic viruses and virally induced cancers)

39. What lymph node drains the rectum (above the pectinate line)?
TNF alpha and IL1
IL 15; IL 12 - interferon Beta and interferon alpha
Glycoproteins; HLA
Internal iliac

40. What are the autoantibodies for Celiac disease?
IgM and IgD
Antigliadin - antiendomysial (both are IgAs - anti tissue transgluataminase igA)
pentamer
Immunoflourescent staining of tissue biopsies

41. which antibodies prevent antigens from binding mucosal surfaces?
Liver! (they are proteins circulating in the blood)
carboxy terminal
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
IgA

42. What is MHC II made out of? Where is it found? What does it bind to? What type of antigens does it present?
Opsonization (Brutons agammaglobulinemia) - adhesion (Leukocyte adhesion defect) - phagocytosis (chediak higashi syndrome) - respiratory burst (chronic granulomatous disease)
Antiviral for uninfected cells (for future protection) and kills virally infected cells (NK activation)
SP infections
An alpha and beta chain; only on APCs; TCR and CD4; extracellular (phagocytosed by APCs)

43. What is the mode of inheritance of Chediak Higashi syndrome? What is the disease d/t? What does it result in? What is the presentation?
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
AR; defect in MT function results in decreased transport and phagocytosis; recurrent pyogenic infections by staphylococci and streptococci - partial albinism - and peripheral neuropathy
Kill them because they have CD16 on them that recognize the FcG portion
Viral neutralization of igM and IgG!

44. What is the autoantibody for SLE that is nonspecific? Specific?
Both decrease cd8 tcell prolif but one through mtor and the other through calcineurin (resp)
encapsulated
Anti nuclear Antibodies (ANA); Anti dsDNA - anti Smith
type four

45. What is the most common example of passive immunity?
IgAs in mothers breast milk!
Suppresses immune response (also specifically Th1 cells) and activates Th2; regulatory T cells
Induces fever - chemokine secretion to recruit - activates adhesion molecules; macrophages
Opsonize bacteria (for enhanced phagocytosis) - neutralize viruses (igG) - activate complement (igM and igG) - sensitize mast cells (igE)

46. what will NK cells do to cells covered in IgG Ab? why?
MHC class molecules bind to KIRS or CD94 to prevent killing
Anticentromere; anti Scl -70 (anti DNA topoisomerase I)
isotype
Kill them because they have CD16 on them that recognize the FcG portion

47. What does IgA pick up from epithelial cells before being secreted?
Interferon gamma and IL 2
Secretory component
MHC class molecules bind to KIRS or CD94 to prevent killing
Bind FcG for antibody dependent cellular cytotoxicity

48. What do multimeric antibodies require for assembly?
MHC II - B7 - CD40 and CD14; CD40 and D14 for FcG and C3b resp
Anti mitochondrial
A j chain
Histamine; post capillary venules - vasodilation

49. What is the white pulp of the spleen?
Surrounds the red pulp and begins with PALS and then turns into follicles with B cells/follicles
Type IV
IgG
By transcytosis

50. What type of fenestrations are found in the red pulp of the spleen?
Barrel hoop basement membrane fenestrations
Antiviral for uninfected cells (for future protection) and kills virally infected cells (NK activation)
Superficial inguinal
...