Test your basic knowledge |

USMLE Step 1 Immunology

Subjects : health-sciences, usmle-step-1

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
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 are the four steps in phagocytosis? What are the four disease that correspond to each step?
Chronic granulomatous disease
Opsonization (Brutons agammaglobulinemia) - adhesion (Leukocyte adhesion defect) - phagocytosis (chediak higashi syndrome) - respiratory burst (chronic granulomatous disease)
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
Remove encapsulated bacateria

2. What are the two signals required for B cell class switching? Which is the second signal?
except hyperacute
CD40 (on b cell) CD40 ligand on Th2 cell; and interleukins (4 -5 -6) from Th2 cell; CD40 is actually the second signal
Antimicrosomal and antithyroglobulin
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

3. What is the white pulp of the spleen?
IgE; by activating eosinophils
Negative!
Surrounds the red pulp and begins with PALS and then turns into follicles with B cells/follicles
Liver! (they are proteins circulating in the blood)

4. What lymph node drains the stomach?
CD56
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
Superficial inguinal
Celiac

5. What is recomb alpha interferon used for?
encapsulated
Lack of NADPH oxidase results in a lack of respiratory burst in neutrophils; susceptibility to catalase positive organisms (S. aureus - E. Coli - Aspergillus)
HBV - HBC - Kaposis - leukemias - malignant melanoma - hairy cell leukemia and condyluma accuminata
Monoclonal Ab to CD3- blocks cellular transduction and signaling of T cells

6. What is the pathology of acute transplant rejection? is it reversible?
Cyclosporine - OKT3
Anti smooth muscle
Vasculitis of graft vessels with dense interstitial lymphocytic infiltrate; yes! with immunosuppressants
Celiac

7. What is three common causes of severe combined immunodef? What is the result of all three?
Adenosine deaminase deficiency (AR) - defective IL 2 receptor (X linked) - and failure to synthesize MHC II; both humoral and cell mediated deficiency
MHC II/CD4 and B7 (on APC) and CD28 (on Th cell); releases cytokines to kill those extracellular buggers!
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
Interferon gamma; Th1

8. which antibodies can bind complement?
dimer
MHC I - CD16 - CD56
IgM and IgG
Anti smooth muscle

9. What are the autoantibodies for other vasculitides?
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 :(
P - ANCA (antimyeloperoxidase); in neutrophil; p= perinuclear
C - ANCA (antiproteinase); in neutrophil; c= cytoplasmic
Previous transfusion; pregnant woman whose fetus had paternal antigens

10. What are the autoantibodies for primary biliary cirrhosis?
Anti mitochondrial
Salmonella - 2 flagellar variants; Borrelia (relapsing fever); and Neisseria gonorrhoaea - pilus protein
When you select for which MHC it will have; take out the lymphs that self react
The antibodies (igM or IgG) either neutralize the target directly (cytoxic!) or recruit leukocytes (Neutrophils and Macrophages!) to incite tissue damage

11. The ______ in the BM are DN - the DP are in the cortex of thymus
T cell precursor
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
Th2; Th1
A recomb cytokine of IL 2; RCC and metastatic melanoma

12. What lymph node drains the breast?
Axillary
DM type I and RA
C5a
Active; passive - fast but short half life (3 weeks!)

13. What type of cells do NK cells attack? with What tools? by necrosis or apoptosis?
Tumor cells and virally infected cells; perforin pore to secrete granzymes through it; apoptosis
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
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
pathogenesis

14. How is sirolimus different from tacrolimus?
except hyperacute
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
Both decrease cd8 tcell prolif but one through mtor and the other through calcineurin (resp)
Graves

15. What are the autoantibodies for pernicious anemia?
Intracellular pathogens (acute and chronic viruses and virally induced cancers)
Delayed type hypersensitivity
Anti TSh receptor
Anti IF

16. What cytokines are released by Th1 cells?
Interferon gamma and IL 2
IL 5
RNA segment reassortment
IL 4

17. What cytokines to Th2 secrete?
IL 4 - 5 - 10 - 6
Anti topoisomerase
opsonizes
If there is class switching and plasma cell production (that is when memory cells are produced)

18. Describe the complement independent Type II hypersenstivity reaction. Give an example.
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
Anti smooth muscle
Make antibody - allergy type 1 (igE) - Cytotoxic and immunecomplex hypersensitivity type II and III (igG); hyperacute organ rejection is Ab mediated
The antibodies (igM or IgG) either neutralize the target directly (cytoxic!) or recruit leukocytes (Neutrophils and Macrophages!) to incite tissue damage

19. What is Aldesleukin? What is it used for
TLR ad nuclear receptors
...
The antibodies (igM or IgG) either neutralize the target directly (cytoxic!) or recruit leukocytes (Neutrophils and Macrophages!) to incite tissue damage
A recomb cytokine of IL 2; RCC and metastatic melanoma

20. What are the autoantibodies for type I diabetes mellitus?
Internal iliac
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
Anti glutamate carboxylase and anti insulin
Lack of NADPH oxidase results in a lack of respiratory burst in neutrophils; susceptibility to catalase positive organisms (S. aureus - E. Coli - Aspergillus)

21. What cytokines do macrophages release? who else can secrete IL 6? IL 12?
pale central germinal centers
Graves
IgA; sinus and lung infections from lack of secretory defense - milk allergies and diarrhea from giardiasis; Anaphylasix on exposure to blood products with igA
IL 1 - IL 6 - IL 12 - TNF alpha; IL 6- Th2 cells; IL 12- B cells

22. What lymph node drains the upper limb?
IL 15; IL 12 - interferon Beta and interferon alpha
MAC (membrane attack complex) Which is activated by C5b - C9 and results in lysis and cytoxicity by creating pores in the target membrane; encapsulated organisms (S. pnuemonia - H.influenzae - B perfussis for example) and other organisms with non pep
Glycoproteins; HLA
Axillary

23. How does the alternative pathway lead to MAC activation?
Immunosuppression after kidney transplantation in combination with cyclosporine and corticosteroids
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
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
Anti IF

24. What is the toxicity of azathioprine?
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
Activate macrophages
...
Lack of response from lymphocytes when activated; because they are self reactive - this is a form of tolerance

25. What is digoxin immune Fab used for?
Bind FcG for antibody dependent cellular cytotoxicity
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
Antidote for digoxin intoxication
By transcytosis

26. What is the toxicity of muromonab?
Cytokine release syndrome due to initial release from initial binding (fever etc) and hypersensitivity reaction
IL 4 -5 -6 for B cell class switching - IL 10 to inhibit TH1
IL 4
Secretory component

27. If the alternative pathway is constitively active - how come normal cells don't get attacked with MAC?
IL 5
DAF and C1 esterase inhibitor on cells prevent complement activation on their surfaces (microbial surfaces lack this)
Recomb cytokine of GCSF (granulocyte macrophage colony stimulating factor; for recovery of bone marrow
Carbohydrate

28. What are C1 - C2 - C3 - C4 important for?
CGD; Jobs syndrome (defect in Neutrophil chemotactic response)
Stimulate the liver to release acute phase reactants
Viral neutralization of igM and IgG!
MS - hay fever - SLE - goodpastures

29. What is epo used for?
The igA found in breast milk
Antigliadin - antiendomysial (both are IgAs - anti tissue transgluataminase igA)
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
Anemias (esp due to renal failure)

30. What is the two fates of the RBCs that go through the spleen? what happens eventually to all of them>
IgM and IgA
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
Cross link antigens which increases their phagocytability; activate complement for MAC attack; opsonization; neutralization
IL 1 - IL 6 - IL 12 - TNF alpha; IL 6- Th2 cells; IL 12- B cells

31. What portion of the lymph node is not well developed in DiGeorge Syndrome?
pale central germinal centers
Paracortex
Anti glutamate carboxylase and anti insulin
Graves

32. What are target cells?
Cells that stil have weird parts of their membrane that macrophages usually bite off
HBV - HBC - Kaposis - leukemias - malignant melanoma - hairy cell leukemia and condyluma accuminata
Increases expression of MHC I and MHC II and also activates NK cells
Antihistone

33. ________ regulate the cell mediated response.
Mycobacterium Tuberculosis - Mycobacterium Avium Intracellulare; Toxoplasmosis Gondii
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 :(
Humoral
Remove encapsulated bacateria

34. Give three examples of bacteria that use antigenic variation and how.
Defect in CD40L results in inability to class switch; a lot of IgM and no IgG - A - E
Mycobacterium Tuberculosis - Mycobacterium Avium Intracellulare; Toxoplasmosis Gondii
Induce differentiation of T cells into Th1 helper cells and activates NK cells also; B cells
Salmonella - 2 flagellar variants; Borrelia (relapsing fever); and Neisseria gonorrhoaea - pilus protein

35. From where do cytokines come from?
pathogenesis
Para aortic
Acts as second signal on B cells to induce class switching to IgA; also stimulates eosinophils
Lymphocytes

36. What are the autoantibodies for graves?
Anti TSh receptor
MHC class molecules bind to KIRS or CD94 to prevent killing
Ischemia and necrosis of graft due to occlusion of vessels and fibrinoid necrosis and thrombosis within the vessels
TNF alpha and IL1

37. What is the main function of IL 8?
A chemotactic factor for neutrophils
Activate B cells - activate Macrophages - kill viruses directly - delayed cell mediated hypersensitivity - acute and chronic rejection
Fab portion
Anti smooth muscle

38. what secretes IL 4?
Influenza; antigenic shift; antigenic drift
Basophils! THey want IG E class switch!
IgM and IgD
The place of T cell diff and maturation; ant mediastinum above heart; yes; 2

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
opsonizes
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
Anti Jo -1

40. What are the autoantibodies for drug induced lupus?
Th1; interferon gamma; IL 2 for cytotoxic T cell activation
Legionella - N. gonorrhea - L. monocytogenes - viruses - protozoa (leismaniasis)
Antihistone
Nuclear remnants that are usually taken out of RBC before complete maturation by Macrophages

41. Which helper T cells' development is induced by IL 4? IL 12?
Th2; Th1
Activate macrophages
Monoclonal Ab to CD3- blocks cellular transduction and signaling of T cells
Anemias (esp due to renal failure)

42. What is the defect in Leukocyte adhesion defect? What is the presentation? What are the labs?
IL 5
MS - hay fever - SLE - goodpastures
Legionella - N. gonorrhea - L. monocytogenes - viruses - protozoa (leismaniasis)
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

43. DTH (delayed type hypersensitivity) is the ________ of a PPD reaction
pathogenesis
Th1; interferon gamma; IL 2 for cytotoxic T cell activation
Alternative splicing of mRNA
Its involved in inflammation and results in anaphylaxis and neutrophil chemotaxis.

44. Complements are...
NK cells
acute phase reactants
IL 4 -5 -6 for B cell class switching - IL 10 to inhibit TH1
Antihistone

45. What are the T cell functions?
Antiviral for uninfected cells (for future protection) and kills virally infected cells (NK activation)
Active; passive - fast but short half life (3 weeks!)
Activate B cells - activate Macrophages - kill viruses directly - delayed cell mediated hypersensitivity - acute and chronic rejection
Anti Ach receptor

46. What bugs can actually infect the lymph node itself?
Leukocyte adhesion defect; ataxia telangietasia; ataxia telangiectasia; chediak higashi syndrome; IgA def; Digeorge syndrome; Jobs; Chediak Higashi
CD40 (on b cell) CD40 ligand on Th2 cell; and interleukins (4 -5 -6) from Th2 cell; CD40 is actually the second signal
Mycobacterium Tuberculosis - Mycobacterium Avium Intracellulare; Toxoplasmosis Gondii
Antimicrosomal and antithyroglobulin

47. In order to produce Antibodies - does the antigen have to be phagocytosed? give an example with a bug and an autoimmune (type II hypersensitivity for example).
False! B cell class switching requires a second signal
No! That is why they are different from T cells - they can recognize antigens in free solution; if a bug has a peptide fragment that a mature naive B cell recognizes it will bind to it and cause activation - it then gets activated into a plasma cell!
Patient has had previous exposure to blood products which result in presence of preformed anti HLA cytotoxic Abs
Internal iliac

48. What are the autoantibodies for hashimotos?
encapsulated
Suppresses immune response (also specifically Th1 cells) and activates Th2; regulatory T cells
Barrel hoop basement membrane fenestrations
Antimicrosomal and antithyroglobulin

49. Give an example of someone who could get hyperacute transplant rejection.
Activates Th1 helper cells; Macrophages
Histamine (causes vasodilation) - leukotrienes (causes bronchoconstriction) - chemotaxins for eos - and heparin (increased blood flow needs to be anticoagulated!)
Intracellular pathogens (acute and chronic viruses and virally induced cancers)
Previous transfusion; pregnant woman whose fetus had paternal antigens

50. what cytokine does basophils secrete?
Antimicrosomal and antithyroglobulin
IL 4
IL 4 - 5 - 10 - 6
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