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 does granzyme do? who secretes it?
Activates Th1 helper cells; Macrophages
Its a serine protease that activates apoptosis; NK and CD8
TGF beta and IL 10
Induces fever - chemokine secretion to recruit - activates adhesion molecules; macrophages

2. __________ are a part of the innate system.
Hereditary angioedema; PNH
NK cells
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
CD40 (on b cell) CD40 ligand on Th2 cell; and interleukins (4 -5 -6) from Th2 cell; CD40 is actually the second signal

3. What is the clinical use for azathioprine?
Cross link
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
Intracellular pathogens (acute and chronic viruses and virally induced cancers)
...

4. What are C1 - C2 - C3 - C4 important for?
Viral neutralization of igM and IgG!
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
IgM and IgD
Acts as second signal on B cells to induce class switching to IgA; also stimulates eosinophils

5. What lymph node drains the testes?
Salmonella - 2 flagellar variants; Borrelia (relapsing fever); and Neisseria gonorrhoaea - pilus protein
Immunosuppression after kidney transplantation
Para aortic
A recomb cytokine of IL 2; RCC and metastatic melanoma

6. What lymph node drains the sigmoid colon?
Delayed type hypersensitivity
Adaptive uses classic pathway to kill; innate uses alternative pathway to kill
Activate B cells - activate Macrophages - kill viruses directly - delayed cell mediated hypersensitivity - acute and chronic rejection
Inferior mesenteric

7. All transplant rejections - _____________ are mediated by Type IV hypersensitivity
except hyperacute
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
cannot cross placenta
Edema and necrosis in that region

8. explain the process from beginning (ie phagocytosis of the peptide) to end of how Abs are formed in Goodpasteurs.
Activates Macrophages and Th1 cells; suppresses Th2 cells; antiviral and antitumor
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
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
Sinusitis - otitis media - pneumonia

9. What are the autoantibodies for hashimotos?
Antimicrosomal and antithyroglobulin
Alternative splicing of mRNA
Cyclosporine and tacrolimus; sirolimus (as well as hyperlipidemia)
Interferon gamma and IL 2

10. What is epo used for?
False! B cell class switching requires a second signal
...
Negative selection
Anemias (esp due to renal failure)

11. which cytokine inhibits TH2 cells? secreted by who?
Interferon gamma; Th1
Anti SS- A (anti RO) and Anti SS- B
Fever - urticaria - arthralgias - proteinuria - lymphadenopathy
Anti alpha subunit 3 of collagen on type IV bm

12. What is the main cytokine that activates eosinophils?
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
Histamine; post capillary venules - vasodilation
A chemotactic factor for neutrophils
IL 5

13. What is an autograft? syngeneic graft? allograft? xenograft? What is an ex of an allograft? xenograft?
pathogenesis
Activates Macrophages and Th1 cells; suppresses Th2 cells; antiviral and antitumor
SP infections
From self; from identical twin or clone; from nonidentical individual of same species; from different species; fetus; pig valve

14. What two ways do you test for a type 1 hypersensitivity reaction? what will you see?
Scratch test - histamine mediated wheal; radioimmunosorbent assay (detects specific IgEs in serum)
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
Ischemia and necrosis of graft due to occlusion of vessels and fibrinoid necrosis and thrombosis within the vessels
A chemotactic factor for neutrophils

15. What is the main cytokine released by T cells? What does it do
IL 3; supports growth and differentiation of bone marrow stem cells
Humoral
Septicemia with neisseria; because at least you have C3 to act like a neutrophilic chemotactic and an acute phase reactant
IgM

16. Name the three opsonins
CRP - C3b - IgM
Anti Ach receptor
Lack of NADPH oxidase results in a lack of respiratory burst in neutrophils; susceptibility to catalase positive organisms (S. aureus - E. Coli - Aspergillus)
Proteins; IgG - IgM - endotoxin (microbial surfaces in general - nonspecific ones also) - mannose binding Lectin; classic - alternative - MB pathway (resp)

17. What is colostrum?
Anti TSh receptor
The igA found in breast milk
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
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

18. How is i Th1 helper cell inhibited?
Graves
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
Cytokine IL 10 secreted by Th2
Anti glutamate carboxylase and anti insulin

19. 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?
Its involved in inflammation and results in anaphylaxis and neutrophil chemotaxis.
Leukocyte adhesion defect; ataxia telangietasia; ataxia telangiectasia; chediak higashi syndrome; IgA def; Digeorge syndrome; Jobs; Chediak Higashi
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
Cytokine release syndrome due to initial release from initial binding (fever etc) and hypersensitivity reaction

20. What is recomb gamma interferon used for?
Pernicious Anemia and Hashimotos
False! B cell class switching requires a second signal
Chronic granulomatous disease
...

21. Which diseases are associated with DR2?
Edema and necrosis in that region
Cross link antigens which increases their phagocytability; activate complement for MAC attack; opsonization; neutralization
DM type I
MS - hay fever - SLE - goodpastures

22. what cell surface marker is used for NK cells as it is unique to them?
Activates cytotoxic CD 8 T cells as second signal
IL 15; IL 12 - interferon Beta and interferon alpha
CD56
Defect in CD40L results in inability to class switch; a lot of IgM and no IgG - A - E

23. How do we use thymus dependent antigens to prevent infection from organisms that lack a peptide component?
Superficial inguinal
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
except hyperacute
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

24. What are the cell surface proteins for Macrophages? which two are for opsonins?
Popliteal
pentamer
T
MHC II - B7 - CD40 and CD14; CD40 and D14 for FcG and C3b resp

25. after C3 spontaneously hydrolyzes to C3b and C3a - what happens to C3a?
Acts as second signal on B cells to induce class switching to IgA; also stimulates eosinophils
Its involved in inflammation and results in anaphylaxis and neutrophil chemotaxis.
Lack of response from lymphocytes when activated; because they are self reactive - this is a form of tolerance
Coarse Faces - cold (noninflamed d/t inability to attract neutrophils) staph abscesses - retained primary teeth - high igE - dermatologic problems (eczema)

26. What are the autoantibodies for Mixed connective tissue disease?
AR; defect in MT function results in decreased transport and phagocytosis; recurrent pyogenic infections by staphylococci and streptococci - partial albinism - and peripheral neuropathy
Anti alpha subunit 3 of collagen on type IV bm
Anti U1 RNP (ribonucleoprotein)
Scratch test - histamine mediated wheal; radioimmunosorbent assay (detects specific IgEs in serum)

27. What are the mediators that mast cells release?
Hyperacute; presence of preformed antibodies in the recipient ( to blood groups or HLA )
IL 4
Histamine (causes vasodilation) - leukotrienes (causes bronchoconstriction) - chemotaxins for eos - and heparin (increased blood flow needs to be anticoagulated!)
Type III hypersensitivity where an internal antigen antibody complexes activate classical complement pathway resulting in C3a neutrophilic chemotaxis and neutrophilic lysosomal death. SLE

28. What are the two signals to kill for NK cells?
By transcytosis
Its a serine protease that activates apoptosis; NK and CD8
Lack of MHC class I constant region which it binds or a nonspecific activation signal (TLR)
No because no peptide fragment!

29. What is the pathogenesis of chronic granulomatous disease; What is the presentation? What is the labs?
IgE; by activating eosinophils
Lack of NADPH oxidase results in a lack of respiratory burst in neutrophils; susceptibility to catalase positive organisms (S. aureus - E. Coli - Aspergillus)
acute phase reactants
Antiviral for uninfected cells (for future protection) and kills virally infected cells (NK activation)

30. What is the symptoms involved in graft versus host disease? it What transplant cases does it usually occur? give an example
Internal iliac
Remove encapsulated bacateria
Cytokine IL 10 secreted by Th2
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

31. What are the autoantibodies for wegeners granulomatosis?
2 heavy chains and two light chains
A B and T cell disorder; defect in DNA repair enzymes; ataxia - telangactasia and IgA def; igA def. and increased AFP
Defect in CD40L results in inability to class switch; a lot of IgM and no IgG - A - E
C - ANCA (antiproteinase); in neutrophil; c= cytoplasmic

32. Which disease is associated with DR3?
DM type I
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
Negative!
Cell mediated due to T cell cytotoxicity reacting to foreign MHCs; few weeks after

33. Describe the interstitial tissue of a spleen including the sinuses. What type of cells are found in the four structures (cortex - paracortex - medulla and sinuses)?
Basophils! THey want IG E class switch!
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
Immune complex - Arthus reaction and Serum sickness; they are all a result of antibody- antigen complex deposition resulting in complement activation
Anti Jo -1

34. which type of immunity is slow but long lasting? as opposed to...
Psoriasis - Ankylosis Spondylitis - IBD - Reiters; all seronegative spondylopathies
Activates cytotoxic CD 8 T cells as second signal
Active; passive - fast but short half life (3 weeks!)
Fab portion

35. which of the IL2 inhibitors produce nephrotoxicity? thrombocytopenia/leukopenia?
Not thymus - BM
opsonizes
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
Cyclosporine and tacrolimus; sirolimus (as well as hyperlipidemia)

36. What does it mean if there are igM in the serum at birth?
From self; from identical twin or clone; from nonidentical individual of same species; from different species; fetus; pig valve
heavy chains
Since cant cross placenta most likely means that child was forced early to produce due to an infection (most likely CMV)
Lack of MHC class I constant region which it binds or a nonspecific activation signal (TLR)

37. What is the antimetabolite precursor of 6 mercaptopurine? What is the result?
Th cells fail to produce interferon gamma; a lot of IgE
...
Activates cytotoxic CD 8 T cells as second signal
Patient has had previous exposure to blood products which result in presence of preformed anti HLA cytotoxic Abs

38. How does complement link innate and adaptive?
N. meningitidis - H. influenzae - S. pneumonia - Salmonella d/t lack of C3b opsonization for MAC d/t lack of complement activation d/t lack of IgM; MAC is needed by encapsulated avoid by humoral and cell mediated through their capsule
Activates cytotoxic CD 8 T cells as second signal
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
Adaptive uses classic pathway to kill; innate uses alternative pathway to kill

39. what results in symptoms of shock in an acute hemolytic transfusion reaction?
Since it is a comp dependent type II hypersensitivity reaction; C3a brings anaphylotoxins that bring in mediators of shock
Fab portion
Its main effect is a defect in Ab opsonization for killing
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

40. are Th cells involved in trapping of antigens of endotoxin/LPS?
No because no peptide fragment!
Superficial inguinal
secondary
Its a serine protease that activates apoptosis; NK and CD8

41. What is the late phase reaction of anaphylaxis allergy? what mediates it?
Recurrent sinopulmonary bacterial infections after 6 months (d/t mothers igGs transplacental) due to opsonization defect
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)
Hyperacute; presence of preformed antibodies in the recipient ( to blood groups or HLA )
Graves

42. Which is the main antibody in the delayed or secondary response to an antigen?
IgG
Immunosuppression after kidney transplantation in combination with cyclosporine and corticosteroids
Anti smooth muscle
Opsonization (Brutons agammaglobulinemia) - adhesion (Leukocyte adhesion defect) - phagocytosis (chediak higashi syndrome) - respiratory burst (chronic granulomatous disease)

43. What does IgA pick up from epithelial cells before being secreted?
Secretory component
Anti mitochondrial
Not thymus - BM
In the germinal center of secondary follicles (In the paler center)

44. The idiotype; the Fc portion determines the...
MHC I - CD16 - CD56
All MHC 1/CD8
Surrounds the red pulp and begins with PALS and then turns into follicles with B cells/follicles
isotype

45. What does IL 4 do?
Cross link antigens which increases their phagocytability; activate complement for MAC attack; opsonization; neutralization
Increases expression of MHC I and MHC II and also activates NK cells
Acts as second signal on B cells to induce class switching to IgE and IgG
IL 1 - IL 6 - IL 12 - TNF alpha; IL 6- Th2 cells; IL 12- B cells

46. what bacteria are a splenectomy patient most susceptible to? why?
Para aortic
N. meningitidis - H. influenzae - S. pneumonia - Salmonella d/t lack of C3b opsonization for MAC d/t lack of complement activation d/t lack of IgM; MAC is needed by encapsulated avoid by humoral and cell mediated through their capsule
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
Macrophages - Dendritic cells - B cells

47. when can graft versus host disease? What is the result?
lowest concentration
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
Barrel hoop basement membrane fenestrations
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

48. A lymph node is a ________ lymphoid organ.
The place of T cell diff and maturation; ant mediastinum above heart; yes; 2
Normal pro B (CD 19 +) - no mature B cells results in decreased total B cell level - and decreased amount of immunoglobulins in each class
Anti smooth muscle
secondary

49. To what portion of the Antibody do the complements bind?
Fc
Ischemia and necrosis of graft due to occlusion of vessels and fibrinoid necrosis and thrombosis within the vessels
When you select for which MHC it will have; take out the lymphs that self react
Celiac

50. Which is the main antibody that provides passive immunity to infants?
Recom IL 11; thrombocytopenia
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
Antimicrosomal and antithyroglobulin
IgG