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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 the main function of TNF alpha? How does it do this?
Immunosuppression after kidney transplantation
CD56
Active; passive - fast but short half life (3 weeks!)
Mediates septic shock; activates the endothelium for adhesion and dilation and leukocyte recruitment results in vascular leak

2. which antibodies can bind complement?
Viral neutralization of igM and IgG!
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
IgAs in mothers breast milk!
IgM and IgG

3. What are the autoantibodies for goodpastures syndrome?
TCR - CD4/8 - CD28 (binds B7) - CD3 (for intracellular transduction) - CD40L
Patient has had previous exposure to blood products which result in presence of preformed anti HLA cytotoxic Abs
Paracortex
Anti alpha subunit 3 of collagen on type IV bm

4. What is the most common selective Ig deficiency? What is the presentation?
Carbohydrate
IgA; sinus and lung infections from lack of secretory defense - milk allergies and diarrhea from giardiasis; Anaphylasix on exposure to blood products with igA
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

5. What lymph node drains the lateral side of the dorsum of the foot?
C5a
In the germinal center of secondary follicles (In the paler center)
Popliteal
A recomb cytokine of IL 2; RCC and metastatic melanoma

6. The idiotype; the Fc portion determines the...
mesenchymal
Rheumatic arthritis
Cell mediated due to T cell cytotoxicity reacting to foreign MHCs; few weeks after
isotype

7. What is passive immunity?
mesenchymal
Receiving preformed Antibodies
Cross link antigens which increases their phagocytability; activate complement for MAC attack; opsonization; neutralization
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

8. 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)
secondary
Th1; interferon gamma; IL 2 for cytotoxic T cell activation
C - ANCA (antiproteinase); in neutrophil; c= cytoplasmic

9. hat is the presentation of Jobs syndrome or Hyper IgE?
Lymphocytes
Coarse Faces - cold (noninflamed d/t inability to attract neutrophils) staph abscesses - retained primary teeth - high igE - dermatologic problems (eczema)
Anemias (esp due to renal failure)
Lack of NADPH oxidase results in a lack of respiratory burst in neutrophils; susceptibility to catalase positive organisms (S. aureus - E. Coli - Aspergillus)

10. What is the presentation of scid? treatment?
Recurrent infections to every type of antigen; bone marrow transplant (be weary of GVH disease!)
Since cant cross placenta most likely means that child was forced early to produce due to an infection (most likely CMV)
Activates cytotoxic CD 8 T cells as second signal
A recomb cytokine of IL 2; RCC and metastatic melanoma

11. what happens in a deficiency of C1 esterase inhibitor? DAF?
Hereditary angioedema; PNH
TLR ad nuclear receptors
Cell mediated due to T cell cytotoxicity reacting to foreign MHCs; few weeks after
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

12. IgG...
opsonizes
IgG and IgM bind to pathogens activating C1 convertase and leads to C2 and C4 and then C3 convertase activated
...
Anti IF

13. What are the autoantibodies for drug induced lupus?
Antihistone
Paracortex
Hyperacute; presence of preformed antibodies in the recipient ( to blood groups or HLA )
Celiac

14. What is the thymus ? Where is it located? is it encapsulated? How many lobes does it have?
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
Fever - urticaria - arthralgias - proteinuria - lymphadenopathy
Kill them because they have CD16 on them that recognize the FcG portion
The place of T cell diff and maturation; ant mediastinum above heart; yes; 2

15. What is the clinical use of Muromonab?
Immunosuppression after kidney transplantation
active complement pathway
Pernicious Anemia and Hashimotos
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

16. A lymph node is a ________ lymphoid organ.
secondary
Recomb cytokine of GCSF (granulocyte macrophage colony stimulating factor; for recovery of bone marrow
carboxy terminal
Anti IF

17. What is the monoclonal antibody to IL2 on activated T cells? What is it used for?
Fibrosis of blood vessels and graft tissue from ischemia; obliterative vascular fibrosis with intimal thickening
In the germinal center of secondary follicles (In the paler center)
Daclizumab; prevent ACUTE rejection of renal transplant
Graves

18. What lymph node drains the upper limb?
Cytokine IL 10 secreted by Th2
Sinusitis - otitis media - pneumonia
Axillary
Hyperacute; presence of preformed antibodies in the recipient ( to blood groups or HLA )

19. What are the major functions of Antibodies?
Anti alpha subunit 3 of collagen on type IV bm
Opsonize bacteria (for enhanced phagocytosis) - neutralize viruses (igG) - activate complement (igM and igG) - sensitize mast cells (igE)
Histamine (causes vasodilation) - leukotrienes (causes bronchoconstriction) - chemotaxins for eos - and heparin (increased blood flow needs to be anticoagulated!)
Activates cytotoxic CD 8 T cells as second signal

20. What is the symptoms involved in graft versus host disease? it What transplant cases does it usually occur? give an example
pale central germinal centers
Intracellular pathogens (acute and chronic viruses and virally induced cancers)
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
Axillary

21. with failed maturation of B cells in Brutons agammaglobulinemia - What is its effect on immune pathways and why?
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
Its main effect is a defect in Ab opsonization for killing
IgG
IgG

22. What are some sinopulmonary infections?
Superficial inguinal
Bind FcG for antibody dependent cellular cytotoxicity
Cross link
Sinusitis - otitis media - pneumonia

23. Which are the only two antiinflammatory cytokines?
Type IV
TGF beta and IL 10
HBV - HBC - Kaposis - leukemias - malignant melanoma - hairy cell leukemia and condyluma accuminata
...

24. What lymph node drains the rectum (above the pectinate line)?
A j chain
IL 4 - 5 - 10 - 6
Internal iliac
Fab portion

25. what secretes IL 4?
Basophils! THey want IG E class switch!
Anti glutamate carboxylase and anti insulin
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
pale central germinal centers

26. What are the three types of APCs?
The patient could become cyanotic in the OR!
Macrophages - Dendritic cells - B cells
No because no peptide fragment!
carboxy terminal

27. Give an example of someone who could get hyperacute transplant rejection.
Previous transfusion; pregnant woman whose fetus had paternal antigens
IL 3; supports growth and differentiation of bone marrow stem cells
MHC I - CD16 - CD56
Anti Jo -1

28. Only the _______ contribute to the Fc region
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
MHC II/CD4 and B7 (on APC) and CD28 (on Th cell); releases cytokines to kill those extracellular buggers!
lowest concentration
heavy chains

29. DTH (delayed type hypersensitivity) is the ________ of a PPD reaction
acute phase reactants
Lack of NADPH oxidase results in a lack of respiratory burst in neutrophils; susceptibility to catalase positive organisms (S. aureus - E. Coli - Aspergillus)
dimer
pathogenesis

30. What cytokines do macrophages release? who else can secrete IL 6? IL 12?
IgE
IL 1 - IL 6 - IL 12 - TNF alpha; IL 6- Th2 cells; IL 12- B cells
Make antibody - allergy type 1 (igE) - Cytotoxic and immunecomplex hypersensitivity type II and III (igG); hyperacute organ rejection is Ab mediated
MHC class molecules bind to KIRS or CD94 to prevent killing

31. What kinds of receptors activate innate immunity?
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
IL 1 - IL 6 - IL 12 - TNF alpha; IL 6- Th2 cells; IL 12- B cells
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
TLR ad nuclear receptors

32. Which disease is associated with B8?
Graves
Proteins; IgG - IgM - endotoxin (microbial surfaces in general - nonspecific ones also) - mannose binding Lectin; classic - alternative - MB pathway (resp)
Type III hypersensitivity where an internal antigen antibody complexes activate classical complement pathway resulting in C3a neutrophilic chemotaxis and neutrophilic lysosomal death. SLE
Carbohydrate

33. What cytokines to Th2 secrete?
A recomb cytokine of IL 2; RCC and metastatic melanoma
IL 4 - 5 - 10 - 6
DM type I and RA
Induce differentiation of T cells into Th1 helper cells and activates NK cells also; B cells

34. what else does interferon gamma do other than inducing ribonuclease production - activating NK cells - inducing increased MHC expression?
pentamer
2 heavy chains and two light chains
CD56
Activate macrophages

35. Which is the most abundant antibody in blood?
Immune complex - Arthus reaction and Serum sickness; they are all a result of antibody- antigen complex deposition resulting in complement activation
IgG
Anti topoisomerase
Induces fever - chemokine secretion to recruit - activates adhesion molecules; macrophages

36. after C3 spontaneously hydrolyzes to C3b and C3a - what happens to C3a?
carboxy terminal
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
Axillary
Its involved in inflammation and results in anaphylaxis and neutrophil chemotaxis.

37. What are target cells?
Th2; Th1
T cell dysfunction
Cells that stil have weird parts of their membrane that macrophages usually bite off
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

38. How is sirolimus different from tacrolimus?
T cell precursor
Both decrease cd8 tcell prolif but one through mtor and the other through calcineurin (resp)
Hemochromatosis
Cyclosporine and tacrolimus; sirolimus (as well as hyperlipidemia)

39. What is serum sickness? give an example.
Since it is a comp dependent type II hypersensitivity reaction; C3a brings anaphylotoxins that bring in mediators of shock
Antiviral for uninfected cells (for future protection) and kills virally infected cells (NK activation)
T cell precursor
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

40. Complements are...
...
acute phase reactants
Activate macrophages
Graves

41. What is the defect in Leukocyte adhesion defect? What is the presentation? What are the labs?
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
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
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
Recurrent infections to every type of antigen; bone marrow transplant (be weary of GVH disease!)

42. Name the three opsonins
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
CRP - C3b - IgM
Anti mitochondrial
IL 1 and IL 6

43. All transplant rejections - _____________ are mediated by Type IV hypersensitivity
Chronic granulomatous disease
except hyperacute
IL 1 - IL 6 - IL 12 - TNF alpha; IL 6- Th2 cells; IL 12- B cells
CD21 on B cells (although there is T cell lymphocytosis in EBV)

44. What is colostrum?
Normal pro B (CD 19 +) - no mature B cells results in decreased total B cell level - and decreased amount of immunoglobulins in each class
The igA found in breast milk
Activates Macrophages and Th1 cells; suppresses Th2 cells; antiviral and antitumor
Lack of MHC class I constant region which it binds or a nonspecific activation signal (TLR)

45. What does Interferon alpha and beta do? how?
MS - hay fever - SLE - goodpastures
Anti topoisomerase
Activates cytotoxic CD 8 T cells as second signal
Antiviral by inducing ribonuclease which degrades only viral mRNA (prevents protein synthesis) and activates NK cells to kill virus infected cells

46. where do NK cells develop?
Acts as second signal on B cells to induce class switching to IgE and IgG
Not thymus - BM
Complement activation (active in both)
Antihistone

47. describe the classic complement pathway.
pathogenesis
Suppresses immune response (also specifically Th1 cells) and activates Th2; regulatory T cells
Histamine (causes vasodilation) - leukotrienes (causes bronchoconstriction) - chemotaxins for eos - and heparin (increased blood flow needs to be anticoagulated!)
IgG and IgM bind to pathogens activating C1 convertase and leads to C2 and C4 and then C3 convertase activated

48. when can graft versus host disease? What is the result?
Hereditary angioedema; PNH
Intracellular pathogens (acute and chronic viruses and virally induced cancers)
Cross link antigens which increases their phagocytability; activate complement for MAC attack; opsonization; neutralization
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

49. Name three things that IL 1 does as a cytokine. other than the liver - who secretes IL 1
Macrophages - Dendritic cells - B cells
Induces fever - chemokine secretion to recruit - activates adhesion molecules; macrophages
Vasculitis of graft vessels with dense interstitial lymphocytic infiltrate; yes! with immunosuppressants
Th cells fail to produce interferon gamma; a lot of IgE

50. What does CD16 on NK cells do?
False! B cell class switching requires a second signal
Both decrease cd8 tcell prolif but one through mtor and the other through calcineurin (resp)
Bind FcG for antibody dependent cellular cytotoxicity
If there is class switching and plasma cell production (that is when memory cells are produced)