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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. Leukocyte adhesion defect presents with...
In the germinal center of secondary follicles (In the paler center)
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)
From self; from identical twin or clone; from nonidentical individual of same species; from different species; fetus; pig valve
neutrophilia!

2. What is the most common selective Ig deficiency? What is the presentation?
IgA; sinus and lung infections from lack of secretory defense - milk allergies and diarrhea from giardiasis; Anaphylasix on exposure to blood products with igA
Recurrent infections to every type of antigen; bone marrow transplant (be weary of GVH disease!)
Th2; Th1
pathogenesis

3. Complements are...
A j chain
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
An anaphylactic immediate reaction; atopy refers to the inherited propensity to develop asthmatic or allergic reactions
acute phase reactants

4. in which immunodef order do you see a lot of pus? no pus?
CGD; Jobs syndrome (defect in Neutrophil chemotactic response)
Since it is a comp dependent type II hypersensitivity reaction; C3a brings anaphylotoxins that bring in mediators of shock
Interferon gamma and IL 2
Thrombocytopenia

5. What are the autoantibodies for systemic sclerosis?
MHC class molecules bind to KIRS or CD94 to prevent killing
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
Anti topoisomerase
heavy chains

6. What happens in a deficiency of C3?
Severe recurrent pyogenic sinus and resp tract And increased susceptibility to type III hypersensitivity like SLE
CGD; Jobs syndrome (defect in Neutrophil chemotactic response)
heavy chains
Superficial inguinal

7. Give an example of someone who could get hyperacute transplant rejection.
Bind FcG for antibody dependent cellular cytotoxicity
Previous transfusion; pregnant woman whose fetus had paternal antigens
Activates cytotoxic CD 8 T cells as second signal
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

8. Describe the capsular structure of a lymph node; What are the functions of the LN?
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
cannot cross placenta
Anti TSh receptor
Tumor cells and virally infected cells; perforin pore to secrete granzymes through it; apoptosis

9. The ______ in the BM are DN - the DP are in the cortex of thymus
T cell precursor
Hemochromatosis
Not thymus - BM
By transcytosis

10. What is a type I hypersensitivity reaction? What is atopic?
Complement activation (active in both)
An anaphylactic immediate reaction; atopy refers to the inherited propensity to develop asthmatic or allergic reactions
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
RNA segment reassortment

11. What are the autoantibodies for drug induced lupus?
Sinusitis - otitis media - pneumonia
Negative!
Antihistone
IL 3; supports growth and differentiation of bone marrow stem cells

12. DTH (delayed type hypersensitivity) is the ________ of a PPD reaction
Paracortex; viral infection
Paracortex
pathogenesis
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

13. What are the two signals to kill for NK cells?
Superficial inguinal
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
Lack of MHC class I constant region which it binds or a nonspecific activation signal (TLR)
except hyperacute

14. What does it mean if there are igM in the serum at birth?
Previous transfusion; pregnant woman whose fetus had paternal antigens
Influenza; antigenic shift; antigenic drift
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
Since cant cross placenta most likely means that child was forced early to produce due to an infection (most likely CMV)

15. What is epo used for?
encapsulated
Coarse Faces - cold (noninflamed d/t inability to attract neutrophils) staph abscesses - retained primary teeth - high igE - dermatologic problems (eczema)
Cytokine IL 10 secreted by Th2
Anemias (esp due to renal failure)

16. What lymph node drains the lateral side of the dorsum of the foot?
In the germinal center of secondary follicles (In the paler center)
They directly stimulate Macrophages by binding CD14; also the alternative complement pathway binds to these host surfaces and induces MAC complex; also TLRs exist for endotoxins; also IgM though not an opsonin can act as a pentamer and trap the antig
Popliteal
Activate B cells - activate Macrophages - kill viruses directly - delayed cell mediated hypersensitivity - acute and chronic rejection

17. What happens when a T helper cell in the paracortical section encounters an antigen? a cytotoxic t cell? a B cell in the cortical section?
Defect in CD40L results in inability to class switch; a lot of IgM and no IgG - A - E
lowest concentration
secondary
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

18. What lymph node drains the thigh?
Antiviral for uninfected cells (for future protection) and kills virally infected cells (NK activation)
Superficial inguinal
Activates cytotoxic CD 8 T cells as second signal
Influenza; antigenic shift; antigenic drift

19. What does granulysin do?
Antimicrobial also secreted by CD8 and NK cells that induces apoptsosis
Opsonize bacteria (for enhanced phagocytosis) - neutralize viruses (igG) - activate complement (igM and igG) - sensitize mast cells (igE)
Secretory component
Local infection/inflammation; infection of the ln itself; metastasis

20. What is the thymus ? Where is it located? is it encapsulated? How many lobes does it have?
Rheumatic arthritis
The place of T cell diff and maturation; ant mediastinum above heart; yes; 2
Mycobacterium Tuberculosis - Mycobacterium Avium Intracellulare; Toxoplasmosis Gondii
Monoclonal Ab to CD3- blocks cellular transduction and signaling of T cells

21. Give three examples of bacteria that use antigenic variation and how.
Alternative splicing of mRNA
Anti TSh receptor
Cell mediated due to T cell cytotoxicity reacting to foreign MHCs; few weeks after
Salmonella - 2 flagellar variants; Borrelia (relapsing fever); and Neisseria gonorrhoaea - pilus protein

22. The two heavy chains of an antibody contribute to the...
Fab portion
secondary
Cyclosporine and tacrolimus; sirolimus (as well as hyperlipidemia)
Recurrent sinopulmonary bacterial infections after 6 months (d/t mothers igGs transplacental) due to opsonization defect

23. What type of side chains are found on Fc region of an antibody?
Glycoproteins; HLA
Rheumatic arthritis
Intracellular pathogens (acute and chronic viruses and virally induced cancers)
Carbohydrate

24. What are the main cell surface proteins on B cells?
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
Ig - CD19 - CD20 - CD21 - CD40 - MHC II - B7
Bind FcG for antibody dependent cellular cytotoxicity
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

25. What is the pathogenesis of chronic transplant rejection? When does it occur? is it reversible?
Influenza; antigenic shift; antigenic drift
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 :(
Ig - CD19 - CD20 - CD21 - CD40 - MHC II - B7
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

26. What is the presentation of Brutons agammaglobulinemia?
Remove encapsulated bacateria
Recurrent sinopulmonary bacterial infections after 6 months (d/t mothers igGs transplacental) due to opsonization defect
Immunosuppression after kidney transplantation
T

27. What is the monoclonal antibody to IL2 on activated T cells? What is it used for?
Antidesmoglein
Daclizumab; prevent ACUTE rejection of renal transplant
MHC I; from RER with help of the B2 microglobulin
Liver! (they are proteins circulating in the blood)

28. What do multimeric antibodies require for assembly?
A j chain
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
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

29. The secondary follicles have __________; primary follicles are dense
dimer
pale central germinal centers
IgA; sinus and lung infections from lack of secretory defense - milk allergies and diarrhea from giardiasis; Anaphylasix on exposure to blood products with igA
MS - hay fever - SLE - goodpastures

30. What are the labs in brutons agammaglobulinemia?
Normal pro B (CD 19 +) - no mature B cells results in decreased total B cell level - and decreased amount of immunoglobulins in each class
neutrophilia!
S. aureus - E. Coli - aspergillus
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 Celiac disease?
Activates Th1 helper cells; Macrophages
C - ANCA (antiproteinase); in neutrophil; c= cytoplasmic
Antigliadin - antiendomysial (both are IgAs - anti tissue transgluataminase igA)
Antidote for digoxin intoxication

32. What is the defect in hyper IgM syndrome? What are the lab results?
Liver! (they are proteins circulating in the blood)
lowest concentration
Defect in CD40L results in inability to class switch; a lot of IgM and no IgG - A - E
Cross link antigens which increases their phagocytability; activate complement for MAC attack; opsonization; neutralization

33. What is chronic mucocutaneous candidiasis d/t?
T cell dysfunction
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
Cells that stil have weird parts of their membrane that macrophages usually bite off
Interferon gamma and IL 2

34. What are the three immune privileged sites? why are they called that? what happens after infection in these areas?
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
Immunosuppression after kidney transplantation in combination with cyclosporine and corticosteroids
Mycobacterium Tuberculosis - Mycobacterium Avium Intracellulare; Toxoplasmosis Gondii
carboxy terminal

35. Which type of selection of thymic development provides central tolerance?
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
Negative selection
Cytokine IL 10 secreted by Th2
Antiviral by inducing ribonuclease which degrades only viral mRNA (prevents protein synthesis) and activates NK cells to kill virus infected cells

36. Which are the only two antiinflammatory cytokines?
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
Anti glutamate carboxylase and anti insulin
active complement pathway
TGF beta and IL 10

37. what happens in a deficiency of C5- C8? why dont you get recurrent pyogenic infections like in C3 def?
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
Septicemia with neisseria; because at least you have C3 to act like a neutrophilic chemotactic and an acute phase reactant
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
Kill them because they have CD16 on them that recognize the FcG portion

38. What part of the complement system also acts as an opsonin? What is opsonization? can you Name two other opsonins?
C3b; coating of a pathogen with molecules that promotes phagocytosis; IgG and CRP
Hemochromatosis
S. aureus - E. Coli - aspergillus
MHC II - B7

39. when can graft versus host disease? What is the result?
Interferon gamma and IL 2
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
Recurrent sinopulmonary bacterial infections after 6 months (d/t mothers igGs transplacental) due to opsonization defect
Paracortex; viral infection

40. Which disease is associated with B8?
Graves
Immunoflourescent staining of tissue biopsies
Bind FcG for antibody dependent cellular cytotoxicity
TNF alpha and IL1

41. What is the presentation of scid? treatment?
lowest concentration
Recurrent sinopulmonary bacterial infections after 6 months (d/t mothers igGs transplacental) due to opsonization defect
T cell dysfunction
Recurrent infections to every type of antigen; bone marrow transplant (be weary of GVH disease!)

42. What are the sinusoids of the spleen? What is the difference between a spleen and a lymph node?
NK cells
Wiskott Aldrich syndrome
Interferon gamma; Th1
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

43. 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)
Psoriasis - Ankylosis Spondylitis - IBD - Reiters; all seronegative spondylopathies
The place of T cell diff and maturation; ant mediastinum above heart; yes; 2
Previous transfusion; pregnant woman whose fetus had paternal antigens

44. What lymph node drains the anal canal (below the pectinate line)?
Superficial inguinal
When you select for which MHC it will have; take out the lymphs that self react
Local infection/inflammation; infection of the ln itself; metastasis
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 :(

45. Type IV hypersensitivity is i...
not Ab mediated
CRP - C3b - IgM
pentamer
IgA; sinus and lung infections from lack of secretory defense - milk allergies and diarrhea from giardiasis; Anaphylasix on exposure to blood products with igA

46. What cytokines do macrophages release? who else can secrete IL 6? IL 12?
IL 1 - IL 6 - IL 12 - TNF alpha; IL 6- Th2 cells; IL 12- B cells
mesenchymal
TNF alpha and IL1
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

47. Which helper T cells' development is induced by IL 4? IL 12?
Both decrease cd8 tcell prolif but one through mtor and the other through calcineurin (resp)
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
2 heavy chains and two light chains
Th2; Th1

48. A lymph node is a ________ lymphoid organ.
The igA found in breast milk
Lymphocytes
Anti IF
secondary

49. Which diseases are associated with DR2?
MS - hay fever - SLE - goodpastures
Humoral
Fc
IgAs in mothers breast milk!

50. What is the most common example of passive immunity?
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
An alpha and beta chain; only on APCs; TCR and CD4; extracellular (phagocytosed by APCs)
IgAs in mothers breast milk!
Decreased Th1 response; disseminated mycobacterial infections; decreased interferon gamma