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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. How is the antigen loaded onto a MHC II?
AR; defect in MT function results in decreased transport and phagocytosis; recurrent pyogenic infections by staphylococci and streptococci - partial albinism - and peripheral neuropathy
Superior mesenteric
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
CGD; Jobs syndrome (defect in Neutrophil chemotactic response)

2. What are the main Cell surface proteins on T cells?
Increases expression of MHC I and MHC II and also activates NK cells
TCR - CD4/8 - CD28 (binds B7) - CD3 (for intracellular transduction) - CD40L
Adaptive uses classic pathway to kill; innate uses alternative pathway to kill
Cyclosporine - OKT3

3. What is chronic mucocutaneous candidiasis d/t?
Pernicious Anemia and Hashimotos
T cell dysfunction
Surrounds the red pulp and begins with PALS and then turns into follicles with B cells/follicles
Anti IF

4. What are the autoantibodies for wegeners granulomatosis?
The patient could become cyanotic in the OR!
Make antibody - allergy type 1 (igE) - Cytotoxic and immunecomplex hypersensitivity type II and III (igG); hyperacute organ rejection is Ab mediated
C - ANCA (antiproteinase); in neutrophil; c= cytoplasmic
The igA found in breast milk

5. what ensure that a memory response is generated?
If there is class switching and plasma cell production (that is when memory cells are produced)
Yes
Fab portion
Antimicrobial also secreted by CD8 and NK cells that induces apoptsosis

6. What is the arthus reaction? What is the difference between arthus and serum sickness? give an example. How do you test for it?
Paracortex
Superficial inguinal
Psoriasis - Ankylosis Spondylitis - IBD - Reiters; all seronegative spondylopathies
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

7. What are the autoantibodies for scleroderma (CREST)? scleroderma diffuse?
Delayed type hypersensitivity
Immunosuppression after kidney transplantation in combination with cyclosporine and corticosteroids
Anticentromere; anti Scl -70 (anti DNA topoisomerase I)
Edema and necrosis in that region

8. give an example of how influenza does a major antigenic shift.
mesenchymal
SP infections
RNA segment reassortment
Sinusitis - otitis media - pneumonia

9. What are MHC Class molecules (ie what macromolecule are they made out of)? what gene are responsible for MHC?
IgA
Glycoproteins; HLA
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)
Psoriasis - Ankylosis Spondylitis - IBD - Reiters; all seronegative spondylopathies

10. What does granzyme do? who secretes it?
Lack of NADPH oxidase results in a lack of respiratory burst in neutrophils; susceptibility to catalase positive organisms (S. aureus - E. Coli - Aspergillus)
Its a serine protease that activates apoptosis; NK and CD8
Adenosine deaminase deficiency (AR) - defective IL 2 receptor (X linked) - and failure to synthesize MHC II; both humoral and cell mediated deficiency
IgA; sinus and lung infections from lack of secretory defense - milk allergies and diarrhea from giardiasis; Anaphylasix on exposure to blood products with igA

11. describe the pathogenesis of delayed type IV hypersensitivity
Lymphocytes
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
T cells react to the angtigen and activate leukocyted (macrophage acitivation)
Immune complex - Arthus reaction and Serum sickness; they are all a result of antibody- antigen complex deposition resulting in complement activation

12. Monomer in circulation - ___ when secreted
dimer
Antiviral by inducing ribonuclease which degrades only viral mRNA (prevents protein synthesis) and activates NK cells to kill virus infected cells
A - B - C; all the D's
Induce differentiation of T cells into Th1 helper cells and activates NK cells also; B cells

13. Which disease is associated with B8?
Glycoproteins; HLA
Internal iliac
Graves
Immune complex - Arthus reaction and Serum sickness; they are all a result of antibody- antigen complex deposition resulting in complement activation

14. What are the cell surface proteins on NK cells?
An anaphylactic immediate reaction; atopy refers to the inherited propensity to develop asthmatic or allergic reactions
MHC I - CD16 - CD56
Secretory component
IL 15; IL 12 - interferon Beta and interferon alpha

15. ________ regulate the cell mediated response.
Humoral
Antihistone
TGF beta and IL 10
Leukocyte adhesion defect; ataxia telangietasia; ataxia telangiectasia; chediak higashi syndrome; IgA def; Digeorge syndrome; Jobs; Chediak Higashi

16. What is MHC II made out of? Where is it found? What does it bind to? What type of antigens does it present?
Axillary
An alpha and beta chain; only on APCs; TCR and CD4; extracellular (phagocytosed by APCs)
Fc
1) susceptibility to encapsulated organisms 2) Howell Jolly Bodies 3) Target cells 4) Thrombocytosis

17. which cells have more complete tolerance - B or T cells?
T
TLR ad nuclear receptors
Its main effect is a defect in Ab opsonization for killing
except hyperacute

18. which antibody activate mast cells - basophils - and eosinophils?
Antihistone
Graves
IgE
HBV - HBC - Kaposis - leukemias - malignant melanoma - hairy cell leukemia and condyluma accuminata

19. What does IL 5 do?
Edema and necrosis in that region
Acts as second signal on B cells to induce class switching to IgA; also stimulates eosinophils
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
Antiviral by inducing ribonuclease which degrades only viral mRNA (prevents protein synthesis) and activates NK cells to kill virus infected cells

20. What are the sinusoids of the spleen? What is the difference between a spleen and a lymph node?
Superior mesenteric
Internal iliac
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
Stimulate the liver to release acute phase reactants

21. What is the pathogenesis of acute transplant rejection? When does it occur?
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)
C3b; coating of a pathogen with molecules that promotes phagocytosis; IgG and CRP
pentamer
Cell mediated due to T cell cytotoxicity reacting to foreign MHCs; few weeks after

22. What cytokines to Th2 secrete?
T
IL 4 - 5 - 10 - 6
Its a serine protease that activates apoptosis; NK and CD8
Scratch test - histamine mediated wheal; radioimmunosorbent assay (detects specific IgEs in serum)

23. Describe the complement independent Type II hypersenstivity reaction. Give an example.
NK cells
The antibodies (igM or IgG) either neutralize the target directly (cytoxic!) or recruit leukocytes (Neutrophils and Macrophages!) to incite tissue damage
Make antibody - allergy type 1 (igE) - Cytotoxic and immunecomplex hypersensitivity type II and III (igG); hyperacute organ rejection is Ab mediated
Hyperacute; presence of preformed antibodies in the recipient ( to blood groups or HLA )

24. Name 5 ways Antibody diversity is generated?
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
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
T cell precursor
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

25. What are the symptoms of serum sickness?
Proteins; IgG - IgM - endotoxin (microbial surfaces in general - nonspecific ones also) - mannose binding Lectin; classic - alternative - MB pathway (resp)
lowest concentration
Fever - urticaria - arthralgias - proteinuria - lymphadenopathy
IgM and IgD

26. What are the autoantibodies for primary biliary cirrhosis?
Opsonize bacteria (for enhanced phagocytosis) - neutralize viruses (igG) - activate complement (igM and igG) - sensitize mast cells (igE)
Anti nuclear Antibodies (ANA); Anti dsDNA - anti Smith
Anti mitochondrial
Its involved in inflammation and results in anaphylaxis and neutrophil chemotaxis.

27. What is immune complex disease? give an example.
Type III hypersensitivity where an internal antigen antibody complexes activate classical complement pathway resulting in C3a neutrophilic chemotaxis and neutrophilic lysosomal death. SLE
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
Stimulate the liver to release acute phase reactants
Type IV

28. What are some sinopulmonary infections?
A - B - C; all the D's
Sinusitis - otitis media - pneumonia
MHC II - B7
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

29. What are the autoantibodies for pernicious anemia?
Trypanosomes with programmed rearrangement (results in recurring fever -- sleeping sickness!)
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
IgG
Anti IF

30. other than C3a - what other complement acts as an anaphyloxin?
Immune complex - Arthus reaction and Serum sickness; they are all a result of antibody- antigen complex deposition resulting in complement activation
Lymphocytes
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
C5a

31. Describe the capsular structure of a lymph node; What are the functions of the LN?
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
Carbohydrate
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
The igA found in breast milk

32. What cytokines do macrophages release? who else can secrete IL 6? IL 12?
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
Nuclear remnants that are usually taken out of RBC before complete maturation by Macrophages
IL 1 - IL 6 - IL 12 - TNF alpha; IL 6- Th2 cells; IL 12- B cells
TGF beta and IL 10

33. which cytokine inhibits TH2 cells? secreted by who?
Interferon gamma; Th1
MHC II/CD4 and B7 (on APC) and CD28 (on Th cell); releases cytokines to kill those extracellular buggers!
Remove encapsulated bacateria
Graves

34. when can graft versus host disease? What is the result?
A - B - C; all the D's
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)
Daclizumab; prevent ACUTE rejection of renal transplant
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

35. Give an example of someone who could get hyperacute transplant rejection.
Previous transfusion; pregnant woman whose fetus had paternal antigens
Anti TSh receptor
neutrophilia!
...

36. Give three examples of bacteria that use antigenic variation and how.
CGD; Jobs syndrome (defect in Neutrophil chemotactic response)
Salmonella - 2 flagellar variants; Borrelia (relapsing fever); and Neisseria gonorrhoaea - pilus protein
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
Cyclosporine - OKT3

37. 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
IL 4
Anti U1 RNP (ribonucleoprotein)
IL 15; IL 12 - interferon Beta and interferon alpha

38. IgM can fix complement but...
cannot cross placenta
Intracellular pathogens (acute and chronic viruses and virally induced cancers)
Histamine; post capillary venules - vasodilation
MHC I - CD16 - CD56

39. The two heavy chains of an antibody contribute to the...
Cross link
IL 1 - IL 6 - IL 12 - TNF alpha; IL 6- Th2 cells; IL 12- B cells
Fab portion
Severe recurrent pyogenic sinus and resp tract And increased susceptibility to type III hypersensitivity like SLE

40. What lymph node drains the rectum (above the pectinate line)?
Chronic granulomatous disease
T
Macrophages - Dendritic cells - B cells
Internal iliac

41. What type of cells do NK cells attack? with What tools? by necrosis or apoptosis?
Defect in BTK a tyrosine kinase gene; failed maturation of B cells; X linked recessive
A B and T cell disorder; defect in DNA repair enzymes; ataxia - telangactasia and IgA def; igA def. and increased AFP
DM type I and RA
Tumor cells and virally infected cells; perforin pore to secrete granzymes through it; apoptosis

42. what prevents NK cells from killing normal cells if their default is to kill?
Periarteriolar lymphatic sheath in the white pulp that surround that dead end of the capillaries in the red pulp - contain T cells
Sinusitis - otitis media - pneumonia
MHC class molecules bind to KIRS or CD94 to prevent killing
Popliteal

43. What is the pathogenesis of IgG AIHA ABO hemolytic disease of a newborn? describe what happens.
Type III hypersensitivity where an internal antigen antibody complexes activate classical complement pathway resulting in C3a neutrophilic chemotaxis and neutrophilic lysosomal death. SLE
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
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
Negative nitroblue tetrazolium reduction test

44. 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)?
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
Recurrent infections to every type of antigen; bone marrow transplant (be weary of GVH disease!)
Acts as second signal on B cells to induce class switching to IgA; also stimulates eosinophils
Anti nuclear Antibodies (ANA); Anti dsDNA - anti Smith

45. What is the pathology in hyperacute transplant rejection?
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
IL 3; supports growth and differentiation of bone marrow stem cells
secondary
Ischemia and necrosis of graft due to occlusion of vessels and fibrinoid necrosis and thrombosis within the vessels

46. What are the two signals required for T cells? what happens after?
Mediates septic shock; activates the endothelium for adhesion and dilation and leukocyte recruitment results in vascular leak
Antibody mediated cytotoxicity; either complement dependent or complement independent
Inferior mesenteric
MHC I/CD8 and IL2/IL 2 Receptor (IL 2 is from Th1!); cytoxicity!

47. What is the difference of IgE AIHA and IgG AIHA if they are both complement dependent type II hypersensitivities?
AR; defect in MT function results in decreased transport and phagocytosis; recurrent pyogenic infections by staphylococci and streptococci - partial albinism - and peripheral neuropathy
Nuclear remnants that are usually taken out of RBC before complete maturation by Macrophages
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
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

48. Which are the only two antiinflammatory cytokines?
TGF beta and IL 10
Nuclear remnants that are usually taken out of RBC before complete maturation by Macrophages
Bind FcG for antibody dependent cellular cytotoxicity
Para aortic

49. IgE has the ___________ in the serum
lowest concentration
Surrounds the red pulp and begins with PALS and then turns into follicles with B cells/follicles
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
Immunosuppression after kidney transplantation

50. which of the IL2 inhibitors produce nephrotoxicity? thrombocytopenia/leukopenia?
T
Fever - urticaria - arthralgias - proteinuria - lymphadenopathy
Cyclosporine and tacrolimus; sirolimus (as well as hyperlipidemia)
Immunoflourescent staining of tissue biopsies