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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. Leukocyte adhesion defect presents with...
Histamine (causes vasodilation) - leukotrienes (causes bronchoconstriction) - chemotaxins for eos - and heparin (increased blood flow needs to be anticoagulated!)
Tetanus - Botulinum - HBV - Rabies
acute phase reactants
neutrophilia!

2. where do NK cells develop?
Immune complex - Arthus reaction and Serum sickness; they are all a result of antibody- antigen complex deposition resulting in complement activation
Fab portion
Immunoflourescent staining of tissue biopsies
Not thymus - BM

3. which antibody is involved in the primary response or immediate response to an antigen?
cannot cross placenta
Antidote for digoxin intoxication
...
IgM

4. What are the main cell surface proteins on B cells?
Ig - CD19 - CD20 - CD21 - CD40 - MHC II - B7
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
Immune complex - Arthus reaction and Serum sickness; they are all a result of antibody- antigen complex deposition resulting in complement activation
Adenosine deaminase deficiency (AR) - defective IL 2 receptor (X linked) - and failure to synthesize MHC II; both humoral and cell mediated deficiency

5. How does complement link innate and adaptive?
Adaptive uses classic pathway to kill; innate uses alternative pathway to kill
Interferon gamma and IL 2
Acts as second signal on B cells to induce class switching to IgE and IgG
Active; passive - fast but short half life (3 weeks!)

6. What are the autoantibodies for other vasculitides?
Anti U1 RNP (ribonucleoprotein)
secondary
Edema and necrosis in that region
P - ANCA (antimyeloperoxidase); in neutrophil; p= perinuclear

7. Which disease is associated withB B27?
Psoriasis - Ankylosis Spondylitis - IBD - Reiters; all seronegative spondylopathies
Edema and necrosis in that region
Anti U1 RNP (ribonucleoprotein)
...

8. What is the two fates of the RBCs that go through the spleen? what happens eventually to all of them>
Activates Th1 helper cells; Macrophages
IgM
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
Immunoflourescent staining of tissue biopsies

9. What are howell jolly bodies?
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
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 IV
Nuclear remnants that are usually taken out of RBC before complete maturation by Macrophages

10. What is the arthus reaction? What is the difference between arthus and serum sickness? give an example. How do you test for it?
Paracortex; viral infection
Mediates septic shock; activates the endothelium for adhesion and dilation and leukocyte recruitment results in vascular leak
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
Interferon gamma; Th1

11. other than eat and bite RBCs what else do Macrophages of spleen do>
Graves
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
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
Remove encapsulated bacateria

12. In thymic development - What is the positive selection? negative selections?
acute phase reactants
When you select for which MHC it will have; take out the lymphs that self react
Antigliadin - antiendomysial (both are IgAs - anti tissue transgluataminase igA)
Edema and necrosis in that region

13. How is i Th1 helper cell inhibited?
Cytokine IL 10 secreted by Th2
IgG
Histamine; post capillary venules - vasodilation
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

14. What does IgA pick up from epithelial cells before being secreted?
Opsonize bacteria (for enhanced phagocytosis) - neutralize viruses (igG) - activate complement (igM and igG) - sensitize mast cells (igE)
Secretory component
Intracellular pathogens (acute and chronic viruses and virally induced cancers)
Cells that stil have weird parts of their membrane that macrophages usually bite off

15. 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)
An alpha chain and a B2 microglobulin; on all nucleated cells; TCR and CD8; intracellular antigens
Hemochromatosis
MHC class molecules bind to KIRS or CD94 to prevent killing

16. The ______ in the BM are DN - the DP are in the cortex of thymus
Inferior mesenteric
T cell precursor
Ig - CD19 - CD20 - CD21 - CD40 - MHC II - B7
Cytokine IL 10 secreted by Th2

17. what will NK cells do to cells covered in IgG Ab? why?
Recurrent sinopulmonary bacterial infections after 6 months (d/t mothers igGs transplacental) due to opsonization defect
Immunosuppression after kidney transplantation in combination with cyclosporine and corticosteroids
Superficial inguinal
Kill them because they have CD16 on them that recognize the FcG portion

18. Which diseases are associated with DR5?
The igA found in breast milk
Pernicious Anemia and Hashimotos
IgG and IgM bind to pathogens activating C1 convertase and leads to C2 and C4 and then C3 convertase activated
Anti IF

19. What are MHC's necessary for? By themselves?
A B and T cell disorder; defect in DNA repair enzymes; ataxia - telangactasia and IgA def; igA def. and increased AFP
Paracortex; viral infection
IgE; by activating eosinophils
T cell activation; no with CD 4 or CD 8

20. which interleukin receptor is required for NK development? activation?
Edema and necrosis in that region
Stimulate the liver to release acute phase reactants
IL 15; IL 12 - interferon Beta and interferon alpha
AR; defect in MT function results in decreased transport and phagocytosis; recurrent pyogenic infections by staphylococci and streptococci - partial albinism - and peripheral neuropathy

21. what cytokine does basophils secrete?
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
Severe pyogenic infections early in life
IL 4
TLR ad nuclear receptors

22. What is muromonab - CD3 (OKT3)
Axillary
Monoclonal Ab to CD3- blocks cellular transduction and signaling of T cells
...
Antibody mediated cytotoxicity; either complement dependent or complement independent

23. What is colostrum?
Previous transfusion; pregnant woman whose fetus had paternal antigens
Anti topoisomerase
The igA found in breast milk
Antidesmoglein

24. What is the difference of IgE AIHA and IgG AIHA if they are both complement dependent type II hypersensitivities?
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
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
Glycoproteins; HLA
Activates Macrophages and Th1 cells; suppresses Th2 cells; antiviral and antitumor

25. What are the autoantibodies for pemphigus bulgaris?
Active; passive - fast but short half life (3 weeks!)
Antidesmoglein
acute phase reactants
MHC class molecules bind to KIRS or CD94 to prevent killing

26. What is Aldesleukin? What is it used for
A recomb cytokine of IL 2; RCC and metastatic melanoma
Interferon gamma and IL 2
Surrounds the red pulp and begins with PALS and then turns into follicles with B cells/follicles
Glycoproteins; HLA

27. What is the pathogenesis of HyperIgE syndrome? What are the labs?
An alpha and beta chain; only on APCs; TCR and CD4; extracellular (phagocytosed by APCs)
TNF alpha and IL1
Th cells fail to produce interferon gamma; a lot of IgE
...

28. Complements are...
An alpha and beta chain; only on APCs; TCR and CD4; extracellular (phagocytosed by APCs)
acute phase reactants
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
Fever - urticaria - arthralgias - proteinuria - lymphadenopathy

29. In general What are T cells good for?
Anti viral and anti tumor
IL 1 and IL 6
A j chain
C3b; coating of a pathogen with molecules that promotes phagocytosis; IgG and CRP

30. Name the three opsonins
Cell mediated due to T cell cytotoxicity reacting to foreign MHCs; few weeks after
CRP - C3b - IgM
From self; from identical twin or clone; from nonidentical individual of same species; from different species; fetus; pig valve
carboxy terminal

31. What are four results of a splenectomy?
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
Wiskott Aldrich syndrome
1) susceptibility to encapsulated organisms 2) Howell Jolly Bodies 3) Target cells 4) Thrombocytosis
Graves

32. Often bacteria are associated with being killed by humoral immunity. Name some bugs that require cell mediated immunity because they evade humoral response
Legionella - N. gonorrhea - L. monocytogenes - viruses - protozoa (leismaniasis)
IgM and IgA
Increases expression of MHC I and MHC II and also activates NK cells
Hyperacute; presence of preformed antibodies in the recipient ( to blood groups or HLA )

33. What is the pathogenesis of chronic granulomatous disease; What is the presentation? What is the labs?
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
Lack of NADPH oxidase results in a lack of respiratory burst in neutrophils; susceptibility to catalase positive organisms (S. aureus - E. Coli - Aspergillus)
Anti topoisomerase
...

34. What are the three types of lymphocytes?
Anti topoisomerase
B - T - and NK cells
MHC I/CD8 and IL2/IL 2 Receptor (IL 2 is from Th1!); cytoxicity!
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

35. What does IL 4 do?
Tetanus - Botulinum - HBV - Rabies
Anti U1 RNP (ribonucleoprotein)
carboxy terminal
Acts as second signal on B cells to induce class switching to IgE and IgG

36. What is the late phase reaction of anaphylaxis allergy? what mediates it?
Bind FcG for antibody dependent cellular cytotoxicity
Histamine; post capillary venules - vasodilation
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)
IgG

37. What does IL 5 do?
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 :(
Acts as second signal on B cells to induce class switching to IgA; also stimulates eosinophils
DAF and C1 esterase inhibitor on cells prevent complement activation on their surfaces (microbial surfaces lack this)
CGD; Jobs syndrome (defect in Neutrophil chemotactic response)

38. Name two endogenous pyrogens
An anaphylactic immediate reaction; atopy refers to the inherited propensity to develop asthmatic or allergic reactions
IL 1 and IL 6
Mediates septic shock; activates the endothelium for adhesion and dilation and leukocyte recruitment results in vascular leak
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

39. What is digoxin immune Fab used for?
Fibrosis of blood vessels and graft tissue from ischemia; obliterative vascular fibrosis with intimal thickening
secondary
Antidote for digoxin intoxication
Humoral

40. where are complements produced?
Liver! (they are proteins circulating in the blood)
If there is class switching and plasma cell production (that is when memory cells are produced)
Monoclonal Ab to CD3- blocks cellular transduction and signaling of T cells
Activates Th1 helper cells; Macrophages

41. How is the antigen loaded onto a MHC II?
Antigliadin - antiendomysial (both are IgAs - anti tissue transgluataminase igA)
MHC II - B7
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
secondary

42. What is the clinical use of Muromonab?
An anaphylactic immediate reaction; atopy refers to the inherited propensity to develop asthmatic or allergic reactions
Salmonella - 2 flagellar variants; Borrelia (relapsing fever); and Neisseria gonorrhoaea - pilus protein
Activates cytotoxic CD 8 T cells as second signal
Immunosuppression after kidney transplantation

43. Which disease is associated with DR3?
DM type I
A - B - C; all the D's
An anaphylactic immediate reaction; atopy refers to the inherited propensity to develop asthmatic or allergic reactions
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

44. What kinds of receptors activate innate immunity?
Hereditary angioedema; PNH
Cell mediated due to T cell cytotoxicity reacting to foreign MHCs; few weeks after
TLR ad nuclear receptors
Anti Jo -1

45. What is MHC I made out of? Where is it found? What does it bind to? What type of antigens does it present?
An alpha chain and a B2 microglobulin; on all nucleated cells; TCR and CD8; intracellular antigens
Salmonella - 2 flagellar variants; Borrelia (relapsing fever); and Neisseria gonorrhoaea - pilus protein
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
Proteins; IgG - IgM - endotoxin (microbial surfaces in general - nonspecific ones also) - mannose binding Lectin; classic - alternative - MB pathway (resp)

46. To what disease do the autoantibodies to IgG (rheumatoid factor)?
Fever - urticaria - arthralgias - proteinuria - lymphadenopathy
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
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
Rheumatic arthritis

47. what happens in a deficiency of C5- C8? why dont you get recurrent pyogenic infections like in C3 def?
...
Septicemia with neisseria; because at least you have C3 to act like a neutrophilic chemotactic and an acute phase reactant
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
Local infection/inflammation; infection of the ln itself; metastasis

48. What is the main cytokine released by T cells? What does it do
A - B - C; all the D's
lowest concentration
The antibodies (igM or IgG) either neutralize the target directly (cytoxic!) or recruit leukocytes (Neutrophils and Macrophages!) to incite tissue damage
IL 3; supports growth and differentiation of bone marrow stem cells

49. What is the treatment of acute transplant rejection?
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
MHC II - B7 - CD40 and CD14; CD40 and D14 for FcG and C3b resp
Proteins; IgG - IgM - endotoxin (microbial surfaces in general - nonspecific ones also) - mannose binding Lectin; classic - alternative - MB pathway (resp)
Cyclosporine - OKT3

50. From where do cytokines come from?
Lymphocytes
Anti Ach receptor
Anti alpha subunit 3 of collagen on type IV bm
IL 3; supports growth and differentiation of bone marrow stem cells