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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 are the autoantibodies for pernicious anemia?
Anti IF
T cell precursor
active complement pathway
carboxy terminal

2. Complements are...
acute phase reactants
active complement pathway
IL 4 - 5 - 10 - 6
Decreased Th1 response; disseminated mycobacterial infections; decreased interferon gamma

3. what cell surface marker is used for NK cells as it is unique to them?
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
IgM and IgD
CD56
pale central germinal centers

4. So antibodies are the effectors for the humoral response. List some of their functions.
Cells that stil have weird parts of their membrane that macrophages usually bite off
IgM and IgG
Cross link antigens which increases their phagocytability; activate complement for MAC attack; opsonization; neutralization
2 heavy chains and two light chains

5. What part of the complement system also acts as an opsonin? What is opsonization? can you Name two other opsonins?
Rheumatic arthritis
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
isotype
C3b; coating of a pathogen with molecules that promotes phagocytosis; IgG and CRP

6. What is the monoclonal antibody to IL2 on activated T cells? What is it used for?
Daclizumab; prevent ACUTE rejection of renal transplant
IL 3; supports growth and differentiation of bone marrow stem cells
Salmonella - 2 flagellar variants; Borrelia (relapsing fever); and Neisseria gonorrhoaea - pilus protein
IgA

7. What is the pathogenesis of a candida skin test?
except hyperacute
Since cant cross placenta most likely means that child was forced early to produce due to an infection (most likely CMV)
Delayed type hypersensitivity
Defect in BTK a tyrosine kinase gene; failed maturation of B cells; X linked recessive

8. Only the _______ contribute to the Fc region
IL 1 and IL 6
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
heavy chains
RNA segment reassortment

9. What is chronic mucocutaneous candidiasis d/t?
Legionella - N. gonorrhea - L. monocytogenes - viruses - protozoa (leismaniasis)
T cell dysfunction
Axillary
Interferon gamma; Th1

10. what cell surface proteins are on all APCs?
Severe recurrent pyogenic sinus and resp tract And increased susceptibility to type III hypersensitivity like SLE
Anti glutamate carboxylase and anti insulin
Anti mitochondrial
MHC II - B7

11. What is the pathology of acute transplant rejection? is it reversible?
Vasculitis of graft vessels with dense interstitial lymphocytic infiltrate; yes! with immunosuppressants
Legionella - N. gonorrhea - L. monocytogenes - viruses - protozoa (leismaniasis)
MHC II - B7
Chronic granulomatous disease

12. Which MHC presents intracellular peptides? how so?
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
Scratch test - histamine mediated wheal; radioimmunosorbent assay (detects specific IgEs in serum)
The igA found in breast milk
MHC I; from RER with help of the B2 microglobulin

13. What lymph node drains the rectum (above the pectinate line)?
Internal iliac
Digeorge syndrome - 22q11 deletion resulting in failure to develop 3rd and 4th pharyngeal pouches; cardiac and great vessel congenital defects - tetany from hypocalcemia - recurrent viral/fungal infections from T cell deficiency; hypoPTH - hypoCa - a
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
Cytokine release syndrome due to initial release from initial binding (fever etc) and hypersensitivity reaction

14. What is the clinical use for sirolimus? what should you combine it with?
Complement activation (active in both)
Anti topoisomerase
Anti U1 RNP (ribonucleoprotein)
Immunosuppression after kidney transplantation in combination with cyclosporine and corticosteroids

15. What is the main function of interferons?
Antiviral for uninfected cells (for future protection) and kills virally infected cells (NK activation)
Fc
RNA segment reassortment
TNF alpha and IL1

16. What is the pathology seen in chronic transplant rejection?
...
dimer
Fibrosis of blood vessels and graft tissue from ischemia; obliterative vascular fibrosis with intimal thickening
Anti IF

17. What is the main function of IL 8?
A chemotactic factor for neutrophils
CD21 on B cells (although there is T cell lymphocytosis in EBV)
Cytokine IL 10 secreted by Th2
Histamine; post capillary venules - vasodilation

18. are Th cells involved in trapping of antigens of endotoxin/LPS?
No because no peptide fragment!
Previous transfusion; pregnant woman whose fetus had paternal antigens
Th1; interferon gamma; IL 2 for cytotoxic T cell activation
TNF alpha and IL1

19. in which immunodef order do you see a lot of pus? no pus?
IL 4
Periarteriolar lymphatic sheath in the white pulp that surround that dead end of the capillaries in the red pulp - contain T cells
CGD; Jobs syndrome (defect in Neutrophil chemotactic response)
Delayed type hypersensitivity

20. What are the mediators that mast cells release?
not Ab mediated
Delayed type hypersensitivity
Edema and necrosis in that region
Histamine (causes vasodilation) - leukotrienes (causes bronchoconstriction) - chemotaxins for eos - and heparin (increased blood flow needs to be anticoagulated!)

21. The alternative pathway is the only constutively...
Yes
active complement pathway
Edema and necrosis in that region
pathogenesis

22. where do NK cells develop?
Not thymus - BM
Tumor cells and virally infected cells; perforin pore to secrete granzymes through it; apoptosis
pale central germinal centers
Fever - urticaria - arthralgias - proteinuria - lymphadenopathy

23. What is the difference of IgE AIHA and IgG AIHA if they are both complement dependent type II hypersensitivities?
Anti U1 RNP (ribonucleoprotein)
When you select for which MHC it will have; take out the lymphs that self react
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 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

24. How is the thymus organized? what happens in each section?
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
Antiviral by inducing ribonuclease which degrades only viral mRNA (prevents protein synthesis) and activates NK cells to kill virus infected cells
Anti topoisomerase
C3b; coating of a pathogen with molecules that promotes phagocytosis; IgG and CRP

25. What do mature naive B lymphocytes express?
MS
Anemias (esp due to renal failure)
Graves
IgM and IgD

26. Which Thelper cell activated Macrophages? by secreting what? what else does Th1 secrete? For what?
Th1; interferon gamma; IL 2 for cytotoxic T cell activation
Decreased Th1 response; disseminated mycobacterial infections; decreased interferon gamma
Superficial inguinal
Anti viral and anti tumor

27. What are the autoantibodies for systemic sclerosis?
Receiving preformed Antibodies
Anti SS- A (anti RO) and Anti SS- B
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
Anti topoisomerase

28. which antibodies can bind complement?
IgAs in mothers breast milk!
The patient could become cyanotic in the OR!
IgM and IgG
IL 4 -5 -6 for B cell class switching - IL 10 to inhibit TH1

29. To what portion of the Antibody do the complements bind?
Fc
T
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
Coarse Faces - cold (noninflamed d/t inability to attract neutrophils) staph abscesses - retained primary teeth - high igE - dermatologic problems (eczema)

30. can igG cross the placenta?
Basophils! THey want IG E class switch!
Yes
pale central germinal centers
Cytokine IL 10 secreted by Th2

31. What cytokines do macrophages release? who else can secrete IL 6? IL 12?
except hyperacute
Superior mesenteric
IL 1 - IL 6 - IL 12 - TNF alpha; IL 6- Th2 cells; IL 12- B cells
Severe pyogenic infections early in life

32. 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)?
Interferon gamma and IL 2
Superficial inguinal
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
Antiviral by inducing ribonuclease which degrades only viral mRNA (prevents protein synthesis) and activates NK cells to kill virus infected cells

33. Which disease is associated with DR3?
MHC II/CD4 and B7 (on APC) and CD28 (on Th cell); releases cytokines to kill those extracellular buggers!
DM type I
carboxy terminal
Surrounds the red pulp and begins with PALS and then turns into follicles with B cells/follicles

34. what happens in a deficiency of C1 esterase inhibitor? DAF?
MHC II - B7 - CD40 and CD14; CD40 and D14 for FcG and C3b resp
Hereditary angioedema; PNH
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
Wiskott Aldrich syndrome

35. What is the presentation of common variable immunodef? and What are the labs?
Type IV
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
Patient has had previous exposure to blood products which result in presence of preformed anti HLA cytotoxic Abs
Anti glutamate carboxylase and anti insulin

36. What is the common variable immunodeficiency ? How is it different from Brutons?
Anti mitochondrial
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
TGF beta and IL 10
pale central germinal centers

37. Give three examples of bacteria that use antigenic variation and how.
Anti smooth muscle
Salmonella - 2 flagellar variants; Borrelia (relapsing fever); and Neisseria gonorrhoaea - pilus protein
DM type I and RA
Activates Th1 helper cells; Macrophages

38. What are the main symptoms of B cell immunodeficiencies?
...
SP infections
Cyclosporine and tacrolimus; sirolimus (as well as hyperlipidemia)
Isotype switching (activated by Th2 cell signals and cytokines) - somatic hypermutation

39. What does IL 5 do?
Acts as second signal on B cells to induce class switching to IgA; also stimulates eosinophils
Th cells fail to produce interferon gamma; a lot of IgE
Proteins; IgG - IgM - endotoxin (microbial surfaces in general - nonspecific ones also) - mannose binding Lectin; classic - alternative - MB pathway (resp)
Intracellular pathogens (acute and chronic viruses and virally induced cancers)

40. Name 5 ways Antibody diversity is generated?
Chronic granulomatous disease
Superior mesenteric
Wiskott Aldrich syndrome
1) VJ light chain random creation 2) VDJ (heavy chain) random creation 3) random combination of light with heavy 4) somatic hypermutation (high frequency mutating that occurs on activation) 5) terminal deoxynucleotidyl transferase (TDT) random additi

41. What is Aldesleukin? What is it used for
C3b; coating of a pathogen with molecules that promotes phagocytosis; IgG and CRP
carboxy terminal
TCR - CD4/8 - CD28 (binds B7) - CD3 (for intracellular transduction) - CD40L
A recomb cytokine of IL 2; RCC and metastatic melanoma

42. To what disease do the autoantibodies to IgG (rheumatoid factor)?
Activates Macrophages and Th1 cells; suppresses Th2 cells; antiviral and antitumor
Rheumatic arthritis
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
Thrombocytopenia

43. What type of fenestrations are found in the red pulp of the spleen?
Anti nuclear Antibodies (ANA); Anti dsDNA - anti Smith
SP infections
Barrel hoop basement membrane fenestrations
Bind FcG for antibody dependent cellular cytotoxicity

44. What is the clinical use for azathioprine?
Its involved in inflammation and results in anaphylaxis and neutrophil chemotaxis.
Recom IL 11; thrombocytopenia
...
Interferon gamma; Th1

45. What are the function of B cells?
Make antibody - allergy type 1 (igE) - Cytotoxic and immunecomplex hypersensitivity type II and III (igG); hyperacute organ rejection is Ab mediated
Induces fever - chemokine secretion to recruit - activates adhesion molecules; macrophages
Stimulate the liver to release acute phase reactants
IL 4

46. How does igA cross the epithelium?
The igA found in breast milk
By transcytosis
Remove encapsulated bacateria
A - B - C; all the D's

47. What part of the lymph node specifically expands during a cellular immune response? when would this occur?
Opsonization (Brutons agammaglobulinemia) - adhesion (Leukocyte adhesion defect) - phagocytosis (chediak higashi syndrome) - respiratory burst (chronic granulomatous disease)
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
Lack of response from lymphocytes when activated; because they are self reactive - this is a form of tolerance
Paracortex; viral infection

48. Which are the only two antiinflammatory cytokines?
IgA
Th1; interferon gamma; IL 2 for cytotoxic T cell activation
Liver! (they are proteins circulating in the blood)
TGF beta and IL 10

49. What is recomb beta interferon used for?
dimer
Interferon gamma; Th1
MS
T cells react to the angtigen and activate leukocyted (macrophage acitivation)

50. All transplant rejections - _____________ are mediated by Type IV hypersensitivity
Stimulate the liver to release acute phase reactants
Mycobacterium Tuberculosis - Mycobacterium Avium Intracellulare; Toxoplasmosis Gondii
Acts as second signal on B cells to induce class switching to IgA; also stimulates eosinophils
except hyperacute