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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. describe the classic complement pathway.
P - ANCA (antimyeloperoxidase); in neutrophil; p= perinuclear
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
IgG and IgM bind to pathogens activating C1 convertase and leads to C2 and C4 and then C3 convertase activated
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

2. What are some sinopulmonary infections?
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
Activate macrophages
Sinusitis - otitis media - pneumonia
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

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

4. What are the two signals to kill for NK cells?
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
Lack of MHC class I constant region which it binds or a nonspecific activation signal (TLR)
opsonizes
IgM and IgA

5. How do you test for chronic granulomatous disease?
Negative nitroblue tetrazolium reduction test
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
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
TNF alpha and IL1

6. What lymph node drains the breast?
Axillary
An alpha and beta chain; only on APCs; TCR and CD4; extracellular (phagocytosed by APCs)
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
Antiviral for uninfected cells (for future protection) and kills virally infected cells (NK activation)

7. after C3 spontaneously hydrolyzes to C3b and C3a - what happens to C3a?
Its involved in inflammation and results in anaphylaxis and neutrophil chemotaxis.
Inferior mesenteric
Anti U1 RNP (ribonucleoprotein)
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

8. What is the pathogenesis of a candida skin test?
Local infection/inflammation; infection of the ln itself; metastasis
A B and T cell disorder; defect in DNA repair enzymes; ataxia - telangactasia and IgA def; igA def. and increased AFP
Delayed type hypersensitivity
Anti nuclear Antibodies (ANA); Anti dsDNA - anti Smith

9. What type of side chains are found on Fc region of an antibody?
TLR ad nuclear receptors
Carbohydrate
...
Superior mesenteric

10. What is hereditary angioedema? What are the C3 levels?
Recomb cytokine of GCSF (granulocyte macrophage colony stimulating factor; for recovery of bone marrow
Antigliadin - antiendomysial (both are IgAs - anti tissue transgluataminase igA)
Thrombocytopenia
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

11. What is the most common selective Ig deficiency? What is the presentation?
Mycobacterium Tuberculosis - Mycobacterium Avium Intracellulare; Toxoplasmosis Gondii
Daclizumab; prevent ACUTE rejection of renal transplant
IgA; sinus and lung infections from lack of secretory defense - milk allergies and diarrhea from giardiasis; Anaphylasix on exposure to blood products with igA
C - ANCA (antiproteinase); in neutrophil; c= cytoplasmic

12. Which disease is associated with DR3?
Not thymus - BM
Coarse Faces - cold (noninflamed d/t inability to attract neutrophils) staph abscesses - retained primary teeth - high igE - dermatologic problems (eczema)
Anti Jo -1
DM type I

13. What are the autoantibodies for hashimotos?
Axillary
TLR ad nuclear receptors
Recurrent sinopulmonary bacterial infections after 6 months (d/t mothers igGs transplacental) due to opsonization defect
Antimicrosomal and antithyroglobulin

14. What is digoxin immune Fab used for?
Antidote for digoxin intoxication
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
Salmonella - 2 flagellar variants; Borrelia (relapsing fever); and Neisseria gonorrhoaea - pilus protein
Coarse Faces - cold (noninflamed d/t inability to attract neutrophils) staph abscesses - retained primary teeth - high igE - dermatologic problems (eczema)

15. What is the marginal zone of the spleen? what happens there?
IL 4 -5 -6 for B cell class switching - IL 10 to inhibit TH1
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
pale central germinal centers
SP infections

16. what else does interferon gamma do other than inducing ribonuclease production - activating NK cells - inducing increased MHC expression?
Activate macrophages
TLR ad nuclear receptors
Activates Th1 helper cells; Macrophages
Glycoproteins; HLA

17. Which antibodies can be multimeric?
IgM and IgA
CD40 (on b cell) CD40 ligand on Th2 cell; and interleukins (4 -5 -6) from Th2 cell; CD40 is actually the second signal
Axillary
T cells react to the angtigen and activate leukocyted (macrophage acitivation)

18. From where do cytokines come from?
Remove encapsulated bacateria
Lymphocytes
Anti Jo -1
Anti nuclear Antibodies (ANA); Anti dsDNA - anti Smith

19. Which are the only two antiinflammatory cytokines?
Graves
Active; passive - fast but short half life (3 weeks!)
TGF beta and IL 10
Antiviral for uninfected cells (for future protection) and kills virally infected cells (NK activation)

20. What is the treatment of acute transplant rejection?
IgG
Cyclosporine - OKT3
Histamine (causes vasodilation) - leukotrienes (causes bronchoconstriction) - chemotaxins for eos - and heparin (increased blood flow needs to be anticoagulated!)
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

21. What is the clinical use for azathioprine?
DAF and C1 esterase inhibitor on cells prevent complement activation on their surfaces (microbial surfaces lack this)
...
Previous transfusion; pregnant woman whose fetus had paternal antigens
Antimicrosomal and antithyroglobulin

22. What is the main function of interferons?
lowest concentration
IL 1 and IL 6
2 heavy chains and two light chains
Antiviral for uninfected cells (for future protection) and kills virally infected cells (NK activation)

23. What is the main function of IL 12? other than macrophages who else can release IL 12?
Secretory component
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
except hyperacute
Induce differentiation of T cells into Th1 helper cells and activates NK cells also; B cells

24. What is the arthus reaction? What is the difference between arthus and serum sickness? give an example. How do you test for it?
Immune complex - Arthus reaction and Serum sickness; they are all a result of antibody- antigen complex deposition resulting in complement activation
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
Fc
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

25. What does IL 10 do? who is secreted by?
Complement activation (active in both)
All MHC 1/CD8
Suppresses immune response (also specifically Th1 cells) and activates Th2; regulatory T cells
Opsonization (Brutons agammaglobulinemia) - adhesion (Leukocyte adhesion defect) - phagocytosis (chediak higashi syndrome) - respiratory burst (chronic granulomatous disease)

26. What is chronic mucocutaneous candidiasis d/t?
T cell dysfunction
Superficial inguinal
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
type four

27. What are the major functions of Antibodies?
Fibrosis of blood vessels and graft tissue from ischemia; obliterative vascular fibrosis with intimal thickening
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
Opsonize bacteria (for enhanced phagocytosis) - neutralize viruses (igG) - activate complement (igM and igG) - sensitize mast cells (igE)
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)

28. Monomer in circulation - ___ when secreted
Antihistone
Fibrosis of blood vessels and graft tissue from ischemia; obliterative vascular fibrosis with intimal thickening
dimer
Nuclear remnants that are usually taken out of RBC before complete maturation by Macrophages

29. What is the presentation of Brutons agammaglobulinemia?
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
heavy chains
Recurrent sinopulmonary bacterial infections after 6 months (d/t mothers igGs transplacental) due to opsonization defect
Nuclear remnants that are usually taken out of RBC before complete maturation by Macrophages

30. What are target cells?
pale central germinal centers
Cells that stil have weird parts of their membrane that macrophages usually bite off
Immune complex - Arthus reaction and Serum sickness; they are all a result of antibody- antigen complex deposition resulting in complement activation
NK cells

31. What is the pathogenesis of HyperIgE syndrome? What are the labs?
MHC I - CD16 - CD56
Th cells fail to produce interferon gamma; a lot of IgE
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
From self; from identical twin or clone; from nonidentical individual of same species; from different species; fetus; pig valve

32. which B and T cell disorder presents with specifically low IgM?
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
Wiskott Aldrich syndrome
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
IgG and IgM bind to pathogens activating C1 convertase and leads to C2 and C4 and then C3 convertase activated

33. What are MHC's necessary for? By themselves?
TCR - CD4/8 - CD28 (binds B7) - CD3 (for intracellular transduction) - CD40L
T cell activation; no with CD 4 or CD 8
Fab portion
Paracortex; viral infection

34. Which helper T cells' development is induced by IL 4? IL 12?
Stimulate the liver to release acute phase reactants
Th2; Th1
acute phase reactants
encapsulated

35. What are the autoantibodies for other vasculitides?
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
DM type I
P - ANCA (antimyeloperoxidase); in neutrophil; p= perinuclear
T cells react to the angtigen and activate leukocyted (macrophage acitivation)

36. The lymphocytes are ________ origin
Periarteriolar lymphatic sheath in the white pulp that surround that dead end of the capillaries in the red pulp - contain T cells
Lack of response from lymphocytes when activated; because they are self reactive - this is a form of tolerance
mesenchymal
The antibodies (igM or IgG) either neutralize the target directly (cytoxic!) or recruit leukocytes (Neutrophils and Macrophages!) to incite tissue damage

37. which cells have more complete tolerance - B or T cells?
Psoriasis - Ankylosis Spondylitis - IBD - Reiters; all seronegative spondylopathies
Hemochromatosis
T
Leukocyte adhesion defect; ataxia telangietasia; ataxia telangiectasia; chediak higashi syndrome; IgA def; Digeorge syndrome; Jobs; Chediak Higashi

38. What is epo used for?
Anemias (esp due to renal failure)
Activates Macrophages and Th1 cells; suppresses Th2 cells; antiviral and antitumor
Its main effect is a defect in Ab opsonization for killing
Increases expression of MHC I and MHC II and also activates NK cells

39. 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; defect in DNA repair enzymes; ataxia - telangactasia and IgA def; igA def. and increased AFP
Legionella - N. gonorrhea - L. monocytogenes - viruses - protozoa (leismaniasis)
IgE; by activating eosinophils
Humoral

40. What lymph node drains the sigmoid colon?
IgG
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
Inferior mesenteric
Acts as second signal on B cells to induce class switching to IgA; also stimulates eosinophils

41. How do you test for type III hypersensitivity?
Cells that stil have weird parts of their membrane that macrophages usually bite off
Immunoflourescent staining of tissue biopsies
Daclizumab; prevent ACUTE rejection of renal transplant
secondary

42. Which is the main antibody in the delayed or secondary response to an antigen?
IgG
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
Carbohydrate
Anti Jo -1

43. What are the autoantibodies for primary biliary cirrhosis?
Anti mitochondrial
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
IgE; by activating eosinophils
1) susceptibility to encapsulated organisms 2) Howell Jolly Bodies 3) Target cells 4) Thrombocytosis

44. What are the two signals required for T cells? what happens after?
Lack of NADPH oxidase results in a lack of respiratory burst in neutrophils; susceptibility to catalase positive organisms (S. aureus - E. Coli - Aspergillus)
Anti viral and anti tumor
MHC I/CD8 and IL2/IL 2 Receptor (IL 2 is from Th1!); cytoxicity!
Axillary

45. What lymph node drains the anal canal (below the pectinate line)?
Superficial inguinal
...
Since cant cross placenta most likely means that child was forced early to produce due to an infection (most likely CMV)
1) susceptibility to encapsulated organisms 2) Howell Jolly Bodies 3) Target cells 4) Thrombocytosis

46. What is oprelevkin? and What is it used for?
CRP - C3b - IgM
Recom IL 11; thrombocytopenia
heavy chains
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

47. What are the four steps in phagocytosis? What are the four disease that correspond to each step?
Opsonization (Brutons agammaglobulinemia) - adhesion (Leukocyte adhesion defect) - phagocytosis (chediak higashi syndrome) - respiratory burst (chronic granulomatous disease)
Antiviral by inducing ribonuclease which degrades only viral mRNA (prevents protein synthesis) and activates NK cells to kill virus infected cells
Receiving preformed Antibodies
MHC II - B7 - CD40 and CD14; CD40 and D14 for FcG and C3b resp

48. What does Interferon alpha and beta do? how?
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
Antiviral by inducing ribonuclease which degrades only viral mRNA (prevents protein synthesis) and activates NK cells to kill virus infected cells
The igA found in breast milk
Local infection/inflammation; infection of the ln itself; metastasis

49. Which diseases are associated with DR5?
MHC I/CD8 and IL2/IL 2 Receptor (IL 2 is from Th1!); cytoxicity!
Since it is a comp dependent type II hypersensitivity reaction; C3a brings anaphylotoxins that bring in mediators of shock
Pernicious Anemia and Hashimotos
HBV - HBC - Kaposis - leukemias - malignant melanoma - hairy cell leukemia and condyluma accuminata

50. Which is the main antibody that provides passive immunity to infants?
IgG
Septicemia with neisseria; because at least you have C3 to act like a neutrophilic chemotactic and an acute phase reactant
An anaphylactic immediate reaction; atopy refers to the inherited propensity to develop asthmatic or allergic reactions
Lack of MHC class I constant region which it binds or a nonspecific activation signal (TLR)