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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 polymyositis and dermatomyositis?
IL 4 - 5 - 10 - 6
Tumor cells and virally infected cells; perforin pore to secrete granzymes through it; apoptosis
IL 1 - IL 6 - IL 12 - TNF alpha; IL 6- Th2 cells; IL 12- B cells
Anti Jo -1

2. What does IL 5 do?
Glycoproteins; HLA
Acts as second signal on B cells to induce class switching to IgA; also stimulates eosinophils
secondary
IgAs in mothers breast milk!

3. with failed maturation of B cells in Brutons agammaglobulinemia - What is its effect on immune pathways and why?
Hemochromatosis
Histamine (causes vasodilation) - leukotrienes (causes bronchoconstriction) - chemotaxins for eos - and heparin (increased blood flow needs to be anticoagulated!)
Its main effect is a defect in Ab opsonization for killing
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

4. What lymph node drains the breast?
Daclizumab; prevent ACUTE rejection of renal transplant
Axillary
heavy chains
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

5. What is the presentation of Brutons agammaglobulinemia?
Cyclosporine and tacrolimus; sirolimus (as well as hyperlipidemia)
Recurrent sinopulmonary bacterial infections after 6 months (d/t mothers igGs transplacental) due to opsonization defect
RNA segment reassortment
IgE; by activating eosinophils

6. what happens in a deficiency of C5- C8? why dont you get recurrent pyogenic infections like in C3 def?
Immunoflourescent staining of tissue biopsies
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
Septicemia with neisseria; because at least you have C3 to act like a neutrophilic chemotactic and an acute phase reactant
Para aortic

7. give an example of how influenza does a major antigenic shift.
RNA segment reassortment
not Ab mediated
Proteins; IgG - IgM - endotoxin (microbial surfaces in general - nonspecific ones also) - mannose binding Lectin; classic - alternative - MB pathway (resp)
NK cells

8. where do somatic hypermutation and class switching occur?
Anti viral and anti tumor
Cross link antigens which increases their phagocytability; activate complement for MAC attack; opsonization; neutralization
In the germinal center of secondary follicles (In the paler center)
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

9. What are four results of a splenectomy?
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
Anti glutamate carboxylase and anti insulin
1) susceptibility to encapsulated organisms 2) Howell Jolly Bodies 3) Target cells 4) Thrombocytosis
pale central germinal centers

10. which immunodeficiency presents with delayed separation of the umbilicus? ataxia? telangiectasia?albinism? anaphylaxis on exposure to blood products with IgA? tetany?retained primary teeth? peripheral neuropathy?
cannot cross placenta
Make antibody - allergy type 1 (igE) - Cytotoxic and immunecomplex hypersensitivity type II and III (igG); hyperacute organ rejection is Ab mediated
A - B - C; all the D's
Leukocyte adhesion defect; ataxia telangietasia; ataxia telangiectasia; chediak higashi syndrome; IgA def; Digeorge syndrome; Jobs; Chediak Higashi

11. What is the mechanism for sirolimus? what else it known as?
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
Macrophages - Dendritic cells - B cells
Local infection/inflammation; infection of the ln itself; metastasis
Its main effect is a defect in Ab opsonization for killing

12. Type Iv hypersensitivity is...
Immunoflourescent staining of tissue biopsies
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
delayed!
Anti topoisomerase

13. What are some sinopulmonary infections?
Activates cytotoxic CD 8 T cells as second signal
Sinusitis - otitis media - pneumonia
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
Negative nitroblue tetrazolium reduction test

14. Which is the main antibody in the delayed or secondary response to an antigen?
...
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
IgG
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!

15. The MALT/GALT are not...
IL 1 and IL 6
IL 4 - 5 - 10 - 6
A - B - C; all the D's
encapsulated

16. DTH (delayed type hypersensitivity) is the ________ of a PPD reaction
Isotype switching (activated by Th2 cell signals and cytokines) - somatic hypermutation
Yes
CD40 (on b cell) CD40 ligand on Th2 cell; and interleukins (4 -5 -6) from Th2 cell; CD40 is actually the second signal
pathogenesis

17. which of the IL2 inhibitors produce nephrotoxicity? thrombocytopenia/leukopenia?
IL 1 and IL 6
Cyclosporine and tacrolimus; sirolimus (as well as hyperlipidemia)
IgG
MHC II - B7 - CD40 and CD14; CD40 and D14 for FcG and C3b resp

18. 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
Nuclear remnants that are usually taken out of RBC before complete maturation by Macrophages
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
Ischemia and necrosis of graft due to occlusion of vessels and fibrinoid necrosis and thrombosis within the vessels

19. can igG cross the placenta?
Proteins; IgG - IgM - endotoxin (microbial surfaces in general - nonspecific ones also) - mannose binding Lectin; classic - alternative - MB pathway (resp)
Yes
Inferior mesenteric
Anti alpha subunit 3 of collagen on type IV bm

20. when can graft versus host disease? What is the result?
TLR ad nuclear receptors
DM type I
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
MS - hay fever - SLE - goodpastures

21. What is the treatment of acute transplant rejection?
acute phase reactants
IL 4 -5 -6 for B cell class switching - IL 10 to inhibit TH1
Immunosuppression after kidney transplantation
Cyclosporine - OKT3

22. which of the transplant rejections is antibody mediated? why does it occur?
cannot cross placenta
Immunosuppression after kidney transplantation in combination with cyclosporine and corticosteroids
Histamine (causes vasodilation) - leukotrienes (causes bronchoconstriction) - chemotaxins for eos - and heparin (increased blood flow needs to be anticoagulated!)
Hyperacute; presence of preformed antibodies in the recipient ( to blood groups or HLA )

23. What are howell jolly bodies?
IgM and IgA
Nuclear remnants that are usually taken out of RBC before complete maturation by Macrophages
Trypanosomes with programmed rearrangement (results in recurring fever -- sleeping sickness!)
Bind FcG for antibody dependent cellular cytotoxicity

24. What is the result of an IL 12 deficiency? What is the presentation? What are the labs?
acute phase reactants
Decreased Th1 response; disseminated mycobacterial infections; decreased interferon gamma
Tumor cells and virally infected cells; perforin pore to secrete granzymes through it; apoptosis
Lack of response from lymphocytes when activated; because they are self reactive - this is a form of tolerance

25. What is the cause of thymic aplasia? What is its presentation? What are the labs?
Superficial inguinal
Recomb cytokine of GCSF (granulocyte macrophage colony stimulating factor; for recovery of bone marrow
C - ANCA (antiproteinase); in neutrophil; c= cytoplasmic
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

26. What is recomb alpha interferon used for?
HBV - HBC - Kaposis - leukemias - malignant melanoma - hairy cell leukemia and condyluma accuminata
Mediates septic shock; activates the endothelium for adhesion and dilation and leukocyte recruitment results in vascular leak
TLR ad nuclear receptors
The place of T cell diff and maturation; ant mediastinum above heart; yes; 2

27. How do you test for type III hypersensitivity?
Lymphocytes
Immunoflourescent staining of tissue biopsies
Chronic granulomatous disease
Previous transfusion; pregnant woman whose fetus had paternal antigens

28. What does IgE do on the surface of the mast cell to induce inflammatory mediator release?
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
Suppresses immune response (also specifically Th1 cells) and activates Th2; regulatory T cells
Cross link
DM type I and RA

29. Name three things that IL 1 does as a cytokine. other than the liver - who secretes IL 1
From self; from identical twin or clone; from nonidentical individual of same species; from different species; fetus; pig valve
Recomb cytokine of GCSF (granulocyte macrophage colony stimulating factor; for recovery of bone marrow
Induces fever - chemokine secretion to recruit - activates adhesion molecules; macrophages
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

30. Which diseases are associated with DR2?
Viral neutralization of igM and IgG!
MS - hay fever - SLE - goodpastures
Opsonize bacteria (for enhanced phagocytosis) - neutralize viruses (igG) - activate complement (igM and igG) - sensitize mast cells (igE)
Acts as second signal on B cells to induce class switching to IgA; also stimulates eosinophils

31. Which antibodies can be multimeric?
IgM and IgA
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
Superior mesenteric
Ig - CD19 - CD20 - CD21 - CD40 - MHC II - B7

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

33. What lymph node drains the scrotum?
Interferon gamma; Th1
Opsonization (Brutons agammaglobulinemia) - adhesion (Leukocyte adhesion defect) - phagocytosis (chediak higashi syndrome) - respiratory burst (chronic granulomatous disease)
Superficial inguinal
Receiving preformed Antibodies

34. are Th cells involved in trapping of antigens of endotoxin/LPS?
pathogenesis
No because no peptide fragment!
Anti alpha subunit 3 of collagen on type IV bm
AR; defect in MT function results in decreased transport and phagocytosis; recurrent pyogenic infections by staphylococci and streptococci - partial albinism - and peripheral neuropathy

35. What lymph node drains the testes?
Hereditary angioedema; PNH
Para aortic
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
P - ANCA (antimyeloperoxidase); in neutrophil; p= perinuclear

36. How is the antigen loaded onto a MHC II?
Rheumatic arthritis
Isotype switching (activated by Th2 cell signals and cytokines) - somatic hypermutation
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
Periarteriolar lymphatic sheath in the white pulp that surround that dead end of the capillaries in the red pulp - contain T cells

37. What is the main cytokine that activates eosinophils?
IL 4 -5 -6 for B cell class switching - IL 10 to inhibit TH1
IL 5
Antihistone
MHC II - B7 - CD40 and CD14; CD40 and D14 for FcG and C3b resp

38. What is epo used for?
Anemias (esp due to renal failure)
Stimulate the liver to release acute phase reactants
Cells that stil have weird parts of their membrane that macrophages usually bite off
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

39. 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
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
Antimicrosomal and antithyroglobulin
Nuclear remnants that are usually taken out of RBC before complete maturation by Macrophages

40. What cytokines are released by Th1 cells?
Interferon gamma and IL 2
Make antibody - allergy type 1 (igE) - Cytotoxic and immunecomplex hypersensitivity type II and III (igG); hyperacute organ rejection is Ab mediated
Anti alpha subunit 3 of collagen on type IV bm
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

41. What are the three immune privileged sites? why are they called that? what happens after infection in these areas?
IL 4 -5 -6 for B cell class switching - IL 10 to inhibit TH1
Lymphocytes
B - T - and NK 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

42. Other than stimulating fever - what else does IL 6 do?
Stimulate the liver to release acute phase reactants
Immune complex - Arthus reaction and Serum sickness; they are all a result of antibody- antigen complex deposition resulting in complement activation
IL 5
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 :(

43. What lymph node drains the upper limb?
Defect in CD40L results in inability to class switch; a lot of IgM and no IgG - A - E
Cell mediated due to T cell cytotoxicity reacting to foreign MHCs; few weeks after
Axillary
A - B - C; all the D's

44. Name two endogenous pyrogens
Decreased Th1 response; disseminated mycobacterial infections; decreased interferon gamma
Immunosuppression after kidney transplantation
MHC I - CD16 - CD56
IL 1 and IL 6

45. What happens in a deficiency of C3?
Anti IF
Pernicious Anemia and Hashimotos
Severe recurrent pyogenic sinus and resp tract And increased susceptibility to type III hypersensitivity like SLE
C5a

46. What is the defect in Leukocyte adhesion defect? What is the presentation? What are the labs?
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
Negative selection
Recom IL 11; thrombocytopenia
Local infection/inflammation; infection of the ln itself; metastasis

47. What part of the complement system also acts as an opsonin? What is opsonization? can you Name two other opsonins?
Interferon gamma and IL 2
HBV - HBC - Kaposis - leukemias - malignant melanoma - hairy cell leukemia and condyluma accuminata
C3b; coating of a pathogen with molecules that promotes phagocytosis; IgG and CRP
...

48. Which diseases are associated with DR4?
DM type I and RA
Pernicious Anemia and Hashimotos
Antidote for digoxin intoxication
Immune complex - Arthus reaction and Serum sickness; they are all a result of antibody- antigen complex deposition resulting in complement activation

49. What is an autograft? syngeneic graft? allograft? xenograft? What is an ex of an allograft? xenograft?
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
An alpha chain and a B2 microglobulin; on all nucleated cells; TCR and CD8; intracellular antigens
Cytokine release syndrome due to initial release from initial binding (fever etc) and hypersensitivity reaction
From self; from identical twin or clone; from nonidentical individual of same species; from different species; fetus; pig valve

50. What lymph node drains the anal canal (below the pectinate line)?
MS - hay fever - SLE - goodpastures
Trypanosomes with programmed rearrangement (results in recurring fever -- sleeping sickness!)
HBV - HBC - Kaposis - leukemias - malignant melanoma - hairy cell leukemia and condyluma accuminata
Superficial inguinal