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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 chronic mucocutaneous candidiasis d/t?
IL 1 - IL 6 - IL 12 - TNF alpha; IL 6- Th2 cells; IL 12- B cells
T cell dysfunction
Pernicious Anemia and Hashimotos
A B and T cell disorder; defect in DNA repair enzymes; ataxia - telangactasia and IgA def; igA def. and increased AFP

2. What is the thymus ? Where is it located? is it encapsulated? How many lobes does it have?
The place of T cell diff and maturation; ant mediastinum above heart; yes; 2
Antigliadin - antiendomysial (both are IgAs - anti tissue transgluataminase igA)
Salmonella - 2 flagellar variants; Borrelia (relapsing fever); and Neisseria gonorrhoaea - pilus protein
Psoriasis - Ankylosis Spondylitis - IBD - Reiters; all seronegative spondylopathies

3. which of the IL2 inhibitors produce nephrotoxicity? thrombocytopenia/leukopenia?
Severe recurrent pyogenic sinus and resp tract And increased susceptibility to type III hypersensitivity like SLE
A j chain
Cyclosporine and tacrolimus; sirolimus (as well as hyperlipidemia)
Anti viral and anti tumor

4. Complements are...
acute phase reactants
Anti smooth muscle
Local infection/inflammation; infection of the ln itself; metastasis
DM type I and RA

5. What are the two signals required for Th1 cells? what happens after then activated?
Rheumatic arthritis
Yes
MHC II/CD4 and B7 (on APC) and CD28 (on Th cell); releases cytokines to kill those extracellular buggers!
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

6. What is the defect in hyper IgM syndrome? What are the lab results?
Coarse Faces - cold (noninflamed d/t inability to attract neutrophils) staph abscesses - retained primary teeth - high igE - dermatologic problems (eczema)
1) susceptibility to encapsulated organisms 2) Howell Jolly Bodies 3) Target cells 4) Thrombocytosis
Yes
Defect in CD40L results in inability to class switch; a lot of IgM and no IgG - A - E

7. The Fc region is found on the...
Anti IF
carboxy terminal
pathogenesis
Ig - CD19 - CD20 - CD21 - CD40 - MHC II - B7

8. DTH (delayed type hypersensitivity) is the ________ of a PPD reaction
Axillary
pathogenesis
Patient has had previous exposure to blood products which result in presence of preformed anti HLA cytotoxic Abs
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

9. Which HLA's are included in MHC I? MHC II?

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10. What is a factor that is a predictor for a bad transplantation?
Anti Ach receptor
S. aureus - E. Coli - aspergillus
Patient has had previous exposure to blood products which result in presence of preformed anti HLA cytotoxic Abs
Opsonize bacteria (for enhanced phagocytosis) - neutralize viruses (igG) - activate complement (igM and igG) - sensitize mast cells (igE)

11. What is the main function of IL 8?
A chemotactic factor for neutrophils
cannot cross placenta
A B and T cell disorder; defect in DNA repair enzymes; ataxia - telangactasia and IgA def; igA def. and increased AFP
Hemochromatosis

12. What lymph node drains the testes?
DM type I
Negative selection
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
Para aortic

13. after C3 spontaneously hydrolyzes to C3b and C3a - what happens to C3a?
No because no peptide fragment!
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
Defect in BTK a tyrosine kinase gene; failed maturation of B cells; X linked recessive
Its involved in inflammation and results in anaphylaxis and neutrophil chemotaxis.

14. where do NK cells develop?
Not thymus - BM
Immunoflourescent staining of tissue biopsies
pale central germinal centers
SP infections

15. Describe the capsular structure of a lymph node; What are the functions of the LN?
Para aortic
Active; passive - fast but short half life (3 weeks!)
Intracellular pathogens (acute and chronic viruses and virally induced cancers)
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

16. can igG cross the placenta?
Trypanosomes with programmed rearrangement (results in recurring fever -- sleeping sickness!)
Mycobacterium Tuberculosis - Mycobacterium Avium Intracellulare; Toxoplasmosis Gondii
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
Yes

17. What are the main cell surface proteins on B cells?
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
Ig - CD19 - CD20 - CD21 - CD40 - MHC II - B7
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 :(
opsonizes

18. What do macrophages secrete that activate Th1 cells to secrete interferon gamma?
Antidote for digoxin intoxication
Secretory component
TNF alpha and IL1
cannot cross placenta

19. In general What are T cells good for?
Negative!
Para aortic
Anti viral and anti tumor
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

20. Which is the main antibody that provides passive immunity to infants?
IgG
TGF beta and IL 10
Antidote for digoxin intoxication
Leukocyte adhesion defect; ataxia telangietasia; ataxia telangiectasia; chediak higashi syndrome; IgA def; Digeorge syndrome; Jobs; Chediak Higashi

21. other than mediating shock - what else does TNF alpha do? who releases it mainly?
...
Activates Th1 helper cells; Macrophages
Normal pro B (CD 19 +) - no mature B cells results in decreased total B cell level - and decreased amount of immunoglobulins in each class
TGF beta and IL 10

22. What is the toxicity of azathioprine?
...
Interferon gamma and IL 2
Th2; Th1
Receiving preformed Antibodies

23. Which disease is associated with DR7?
Pernicious Anemia and Hashimotos
Paracortex
Steroid responsive nephrotic syndrome
Liver! (they are proteins circulating in the blood)

24. What are the autoantibodies for pernicious anemia?
Normal pro B (CD 19 +) - no mature B cells results in decreased total B cell level - and decreased amount of immunoglobulins in each class
IL 4 -5 -6 for B cell class switching - IL 10 to inhibit TH1
Antiviral for uninfected cells (for future protection) and kills virally infected cells (NK activation)
Anti IF

25. Which is the most abundant antibody in blood?
Recurrent sinopulmonary bacterial infections after 6 months (d/t mothers igGs transplacental) due to opsonization defect
IgG
pathogenesis
Severe pyogenic infections early in life

26. What is passive immunity?
Antiviral for uninfected cells (for future protection) and kills virally infected cells (NK activation)
Receiving preformed Antibodies
carboxy terminal
Both decrease cd8 tcell prolif but one through mtor and the other through calcineurin (resp)

27. What are the four steps in phagocytosis? What are the four disease that correspond to each step?
type four
dimer
Opsonization (Brutons agammaglobulinemia) - adhesion (Leukocyte adhesion defect) - phagocytosis (chediak higashi syndrome) - respiratory burst (chronic granulomatous disease)
IgG and IgM bind to pathogens activating C1 convertase and leads to C2 and C4 and then C3 convertase activated

28. What are some sinopulmonary infections?
Sinusitis - otitis media - pneumonia
Hemochromatosis
Antibody mediated cytotoxicity; either complement dependent or complement independent
Chronic granulomatous disease

29. All transplant rejections - _____________ are mediated by Type IV hypersensitivity
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
type four
Ig - CD19 - CD20 - CD21 - CD40 - MHC II - B7
except hyperacute

30. what cell surface proteins are on all APCs?
If there is class switching and plasma cell production (that is when memory cells are produced)
MHC II - B7
Anti smooth muscle
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

31. 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).
opsonizes
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!
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
Adaptive uses classic pathway to kill; innate uses alternative pathway to kill

32. which antibody activate mast cells - basophils - and eosinophils?
Tetanus - Botulinum - HBV - Rabies
pentamer
IgE
S. aureus - E. Coli - aspergillus

33. which of the hypersensitivity reactions is not Ab mediated?
From self; from identical twin or clone; from nonidentical individual of same species; from different species; fetus; pig valve
Daclizumab; prevent ACUTE rejection of renal transplant
The antibodies (igM or IgG) either neutralize the target directly (cytoxic!) or recruit leukocytes (Neutrophils and Macrophages!) to incite tissue damage
Type IV

34. What is oprelevkin? and What is it used for?
heavy chains
Recom IL 11; thrombocytopenia
Paracortex; viral infection
Mycobacterium Tuberculosis - Mycobacterium Avium Intracellulare; Toxoplasmosis Gondii

35. What is muromonab - CD3 (OKT3)
Opsonization (Brutons agammaglobulinemia) - adhesion (Leukocyte adhesion defect) - phagocytosis (chediak higashi syndrome) - respiratory burst (chronic granulomatous disease)
A - B - C; all the D's
opsonizes
Monoclonal Ab to CD3- blocks cellular transduction and signaling of T cells

36. The idiotype; the Fc portion determines the...
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
isotype
IL 4
IgM

37. which of the transplant rejections is antibody mediated? why does it occur?
Hyperacute; presence of preformed antibodies in the recipient ( to blood groups or HLA )
Cyclosporine - OKT3
type four
Opsonize bacteria (for enhanced phagocytosis) - neutralize viruses (igG) - activate complement (igM and igG) - sensitize mast cells (igE)

38. What does interferon gamma do to be antiviral?
not Ab mediated
Lack of MHC class I constant region which it binds or a nonspecific activation signal (TLR)
SP infections
Increases expression of MHC I and MHC II and also activates NK cells

39. Leukocyte adhesion defect presents with...
neutrophilia!
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
Tetanus - Botulinum - HBV - Rabies
CD21 on B cells (although there is T cell lymphocytosis in EBV)

40. What happens in a deficiency of C3?
MHC I - CD16 - CD56
CD40 (on b cell) CD40 ligand on Th2 cell; and interleukins (4 -5 -6) from Th2 cell; CD40 is actually the second signal
Severe recurrent pyogenic sinus and resp tract And increased susceptibility to type III hypersensitivity like SLE
Antidote for digoxin intoxication

41. What are the main symptoms of T cell immunodeficiencies?
Negative!
Axillary
Intracellular pathogens (acute and chronic viruses and virally induced cancers)
Activate macrophages

42. What are the mediators that mast cells release?
Anemias (esp due to renal failure)
Superficial inguinal
Histamine (causes vasodilation) - leukotrienes (causes bronchoconstriction) - chemotaxins for eos - and heparin (increased blood flow needs to be anticoagulated!)
An alpha chain and a B2 microglobulin; on all nucleated cells; TCR and CD8; intracellular antigens

43. What lymph node drains the duodenum - jejunum?
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
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
Superior mesenteric
TCR - CD4/8 - CD28 (binds B7) - CD3 (for intracellular transduction) - CD40L

44. What lymph node drains the thigh?
AR; defect in MT function results in decreased transport and phagocytosis; recurrent pyogenic infections by staphylococci and streptococci - partial albinism - and peripheral neuropathy
Immunosuppression after kidney transplantation
Influenza; antigenic shift; antigenic drift
Superficial inguinal

45. describe the pathogenesis of delayed type IV hypersensitivity
Anti viral and anti tumor
By transcytosis
T cells react to the angtigen and activate leukocyted (macrophage acitivation)
An alpha and beta chain; only on APCs; TCR and CD4; extracellular (phagocytosed by APCs)

46. What are the autoantibodies for myasthenia gravis?
Anti Ach receptor
Recurrent sinopulmonary bacterial infections after 6 months (d/t mothers igGs transplacental) due to opsonization defect
MHC II/CD4 and B7 (on APC) and CD28 (on Th cell); releases cytokines to kill those extracellular buggers!
S. aureus - E. Coli - aspergillus

47. give an example of how influenza does a major antigenic shift.
dimer
Isotype switching (activated by Th2 cell signals and cytokines) - somatic hypermutation
RNA segment reassortment
IL 1 and IL 6

48. What are C1 - C2 - C3 - C4 important for?
Pernicious Anemia and Hashimotos
Fab portion
Viral neutralization of igM and IgG!
Suppresses immune response (also specifically Th1 cells) and activates Th2; regulatory T cells

49. What are the autoantibodies for sjorgens syndrome?
Cyclosporine - OKT3
Anti SS- A (anti RO) and Anti SS- B
In the germinal center of secondary follicles (In the paler center)
Internal iliac

50. What is hereditary angioedema? What are the C3 levels?
IgA
Anti smooth muscle
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
Type IV