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. 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
Since cant cross placenta most likely means that child was forced early to produce due to an infection (most likely CMV)
Adenosine deaminase deficiency (AR) - defective IL 2 receptor (X linked) - and failure to synthesize MHC II; both humoral and cell mediated deficiency
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!

2. Type IV hypersensitivity is i...
Cells that stil have weird parts of their membrane that macrophages usually bite off
not Ab mediated
Since cant cross placenta most likely means that child was forced early to produce due to an infection (most likely CMV)
pathogenesis

3. The lymphocytes are ________ origin
mesenchymal
IgA; sinus and lung infections from lack of secretory defense - milk allergies and diarrhea from giardiasis; Anaphylasix on exposure to blood products with igA
Opsonize bacteria (for enhanced phagocytosis) - neutralize viruses (igG) - activate complement (igM and igG) - sensitize mast cells (igE)
Negative selection

4. What does IL 4 do?
Leukocyte adhesion defect; ataxia telangietasia; ataxia telangiectasia; chediak higashi syndrome; IgA def; Digeorge syndrome; Jobs; Chediak Higashi
Histamine; post capillary venules - vasodilation
Type IV
Acts as second signal on B cells to induce class switching to IgE and IgG

5. which antibodies can bind complement?
Humoral
CD40 (on b cell) CD40 ligand on Th2 cell; and interleukins (4 -5 -6) from Th2 cell; CD40 is actually the second signal
Antiviral by inducing ribonuclease which degrades only viral mRNA (prevents protein synthesis) and activates NK cells to kill virus infected cells
IgM and IgG

6. What are the cell surface proteins on NK cells?
MHC I - CD16 - CD56
The igA found in breast milk
Sinusitis - otitis media - pneumonia
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

7. what else does interferon gamma do other than inducing ribonuclease production - activating NK cells - inducing increased MHC expression?
An anaphylactic immediate reaction; atopy refers to the inherited propensity to develop asthmatic or allergic reactions
Cytokine IL 10 secreted by Th2
Activate macrophages
Axillary

8. other than eat and bite RBCs what else do Macrophages of spleen do>
TNF alpha and IL1
Antimicrobial also secreted by CD8 and NK cells that induces apoptsosis
Remove encapsulated bacateria
Complement activation (active in both)

9. what bacteria are a splenectomy patient most susceptible to? why?
secondary
A B and T cell disorder; defect in DNA repair enzymes; ataxia - telangactasia and IgA def; igA def. and increased AFP
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
All MHC 1/CD8

10. What are the autoantibodies for drug induced lupus?
Cross link
Suppresses immune response (also specifically Th1 cells) and activates Th2; regulatory T cells
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
Antihistone

11. What do multimeric antibodies require for assembly?
Recurrent sinopulmonary bacterial infections after 6 months (d/t mothers igGs transplacental) due to opsonization defect
Recomb cytokine of GCSF (granulocyte macrophage colony stimulating factor; for recovery of bone marrow
A j chain
MHC II - B7 - CD40 and CD14; CD40 and D14 for FcG and C3b resp

12. IgM can exist as a _______ also
Edema and necrosis in that region
An alpha chain and a B2 microglobulin; on all nucleated cells; TCR and CD8; intracellular antigens
pentamer
cannot cross placenta

13. What is the monoclonal antibody to IL2 on activated T cells? What is it used for?
An alpha chain and a B2 microglobulin; on all nucleated cells; TCR and CD8; intracellular antigens
Daclizumab; prevent ACUTE rejection of renal transplant
Not thymus - BM
A B and T cell disorder; defect in DNA repair enzymes; ataxia - telangactasia and IgA def; igA def. and increased AFP

14. What is the pathogenesis of chronic transplant rejection? When does it occur? is it reversible?
Salmonella - 2 flagellar variants; Borrelia (relapsing fever); and Neisseria gonorrhoaea - pilus protein
Complement activation (active in both)
Viral neutralization of igM and IgG!
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 :(

15. What kinds of receptors activate innate immunity?
Cyclosporine and tacrolimus; sirolimus (as well as hyperlipidemia)
CD56
TLR ad nuclear receptors
Anti topoisomerase

16. Which antibody mediates immunity to worms? how?
Septicemia with neisseria; because at least you have C3 to act like a neutrophilic chemotactic and an acute phase reactant
Cell mediated due to T cell cytotoxicity reacting to foreign MHCs; few weeks after
IgE; by activating eosinophils
Internal iliac

17. Which disease is associated with B8?
Stimulate the liver to release acute phase reactants
Activates Macrophages and Th1 cells; suppresses Th2 cells; antiviral and antitumor
Graves
MHC I; from RER with help of the B2 microglobulin

18. What is chronic mucocutaneous candidiasis d/t?
T cell dysfunction
Popliteal
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
TLR ad nuclear receptors

19. What is the presentation of Brutons agammaglobulinemia?
Glycoproteins; HLA
Legionella - N. gonorrhea - L. monocytogenes - viruses - protozoa (leismaniasis)
Recurrent sinopulmonary bacterial infections after 6 months (d/t mothers igGs transplacental) due to opsonization defect
IgE; by activating eosinophils

20. What are the three types of Type III hypersensitivity ? What is the common mechanism between them?
lowest concentration
From self; from identical twin or clone; from nonidentical individual of same species; from different species; fetus; pig valve
Immune complex - Arthus reaction and Serum sickness; they are all a result of antibody- antigen complex deposition resulting in complement activation
TNF alpha and IL1

21. which interleukin receptor is required for NK development? activation?
T cells react to the angtigen and activate leukocyted (macrophage acitivation)
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
Not thymus - BM
IL 15; IL 12 - interferon Beta and interferon alpha

22. What is the main function of interferons?
Antiviral for uninfected cells (for future protection) and kills virally infected cells (NK activation)
No because no peptide fragment!
Recomb cytokine of GCSF (granulocyte macrophage colony stimulating factor; for recovery of bone marrow
Hereditary angioedema; PNH

23. ________ regulate the cell mediated response.
The place of T cell diff and maturation; ant mediastinum above heart; yes; 2
Lymphocytes
Lack of MHC class I constant region which it binds or a nonspecific activation signal (TLR)
Humoral

24. What is recomb gamma interferon used for?
Anticentromere; anti Scl -70 (anti DNA topoisomerase I)
Edema and necrosis in that region
Steroid responsive nephrotic syndrome
Chronic granulomatous disease

25. which cells have more complete tolerance - B or T cells?
T
IL 1 and IL 6
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
MHC I; from RER with help of the B2 microglobulin

26. How does igA cross the epithelium?
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
By transcytosis
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
Pernicious Anemia and Hashimotos

27. Describe complement dependent Type II hypersensitivity. Give an example.
Its main effect is a defect in Ab opsonization for 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
Interferon gamma; Th1
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

28. What is the autoantibody for SLE that is nonspecific? Specific?
Trypanosomes with programmed rearrangement (results in recurring fever -- sleeping sickness!)
Anti nuclear Antibodies (ANA); Anti dsDNA - anti Smith
Antimicrobial also secreted by CD8 and NK cells that induces apoptsosis
Suppresses immune response (also specifically Th1 cells) and activates Th2; regulatory T cells

29. What is the main function of IL 8?
CD40 (on b cell) CD40 ligand on Th2 cell; and interleukins (4 -5 -6) from Th2 cell; CD40 is actually the second signal
CD56
A chemotactic factor for neutrophils
Immunoflourescent staining of tissue biopsies

30. If an antigen lacks a peptide component How does the adaptive immunity attack it? What type of response is this called. give an example of bugs that do this. what implications does this have on splenectomy?
IgM and IgG
Intracellular pathogens (acute and chronic viruses and virally induced cancers)
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
Lack of MHC class I constant region which it binds or a nonspecific activation signal (TLR)

31. what ensure that a memory response is generated?
If there is class switching and plasma cell production (that is when memory cells are produced)
Inferior mesenteric
Antigliadin - antiendomysial (both are IgAs - anti tissue transgluataminase igA)
Induces fever - chemokine secretion to recruit - activates adhesion molecules; macrophages

32. What is the mechanism for sirolimus? what else it known as?
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
Remove encapsulated bacateria
Coarse Faces - cold (noninflamed d/t inability to attract neutrophils) staph abscesses - retained primary teeth - high igE - dermatologic problems (eczema)
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

33. Other than stimulating fever - what else does IL 6 do?
Intracellular pathogens (acute and chronic viruses and virally induced cancers)
IgM and IgA
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
Stimulate the liver to release acute phase reactants

34. Which TCR MHC system is important for viral immunity? neoplastic? donor graft cells?
Interferon gamma; Th1
All MHC 1/CD8
Opsonize bacteria (for enhanced phagocytosis) - neutralize viruses (igG) - activate complement (igM and igG) - sensitize mast cells (igE)
CD56

35. __________ are a part of the innate system.
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
Internal iliac
NK cells
except hyperacute

36. What is an autograft? syngeneic graft? allograft? xenograft? What is an ex of an allograft? xenograft?
From self; from identical twin or clone; from nonidentical individual of same species; from different species; fetus; pig valve
DAF and C1 esterase inhibitor on cells prevent complement activation on their surfaces (microbial surfaces lack this)
Cells that stil have weird parts of their membrane that macrophages usually bite off
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

37. What is the common variable immunodeficiency ? How is it different from Brutons?
C - ANCA (antiproteinase); in neutrophil; c= cytoplasmic
A B and T cell disorder; defect in DNA repair enzymes; ataxia - telangactasia and IgA def; igA def. and increased AFP
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
Cytokine IL 10 secreted by Th2

38. What is the most common example of passive immunity?
IL 4 - 5 - 10 - 6
IgAs in mothers breast milk!
Leukocyte adhesion defect; ataxia telangietasia; ataxia telangiectasia; chediak higashi syndrome; IgA def; Digeorge syndrome; Jobs; Chediak Higashi
Activates Th1 helper cells; Macrophages

39. What are the two signals required for Th1 cells? what happens after then activated?
Fc
Daclizumab; prevent ACUTE rejection of renal transplant
MAC (membrane attack complex) Which is activated by C5b - C9 and results in lysis and cytoxicity by creating pores in the target membrane; encapsulated organisms (S. pnuemonia - H.influenzae - B perfussis for example) and other organisms with non pep
MHC II/CD4 and B7 (on APC) and CD28 (on Th cell); releases cytokines to kill those extracellular buggers!

40. The ______ in the BM are DN - the DP are in the cortex of thymus
NK cells
T cell precursor
Cells that stil have weird parts of their membrane that macrophages usually bite off
Negative!

41. What are the autoantibodies for Mixed connective tissue disease?
Immune complex - Arthus reaction and Serum sickness; they are all a result of antibody- antigen complex deposition resulting in complement activation
Viral neutralization of igM and IgG!
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
Anti U1 RNP (ribonucleoprotein)

42. describe the pathogenesis of delayed type IV hypersensitivity
All MHC 1/CD8
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
T cells react to the angtigen and activate leukocyted (macrophage acitivation)
S. aureus - E. Coli - aspergillus

43. Which diseases are associated with DR5?
C5a
Superficial inguinal
HBV - HBC - Kaposis - leukemias - malignant melanoma - hairy cell leukemia and condyluma accuminata
Pernicious Anemia and Hashimotos

44. What is the presentation of common variable immunodef? and What are the labs?
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
Suppresses immune response (also specifically Th1 cells) and activates Th2; regulatory T cells
HBV - HBC - Kaposis - leukemias - malignant melanoma - hairy cell leukemia and condyluma accuminata
Tetanus - Botulinum - HBV - Rabies

45. For which toxins are preformed antibodies (passive) given?
Tetanus - Botulinum - HBV - Rabies
An alpha and beta chain; only on APCs; TCR and CD4; extracellular (phagocytosed by APCs)
TGF beta and IL 10
Salmonella - 2 flagellar variants; Borrelia (relapsing fever); and Neisseria gonorrhoaea - pilus protein

46. after C3 spontaneously hydrolyzes to C3b and C3a - what happens to C3a?
neutrophilia!
Cyclosporine and tacrolimus; sirolimus (as well as hyperlipidemia)
Its involved in inflammation and results in anaphylaxis and neutrophil chemotaxis.
Vasculitis of graft vessels with dense interstitial lymphocytic infiltrate; yes! with immunosuppressants

47. 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
Antihistone
NK cells

48. Name three things that IL 1 does as a cytokine. other than the liver - who secretes IL 1
Patient has had previous exposure to blood products which result in presence of preformed anti HLA cytotoxic Abs
Bind FcG for antibody dependent cellular cytotoxicity
Induces fever - chemokine secretion to recruit - activates adhesion molecules; macrophages
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

49. Which diseases are associated with DR4?
DM type I and RA
Nuclear remnants that are usually taken out of RBC before complete maturation by Macrophages
Paracortex
Th cells fail to produce interferon gamma; a lot of IgE

50. What are the autoantibodies for Celiac disease?
Antigliadin - antiendomysial (both are IgAs - anti tissue transgluataminase igA)
encapsulated
When you select for which MHC it will have; take out the lymphs that self react
Anti mitochondrial