immuno practice exam 1

The release of type-1 IFN by a cell can result in stimulation of IFNAR on the same cell. This is best described as which of the following 

a. autocrine signaling 

b. paracrine signaling

 c.endocrine signaling 

d. juxtacrine signaling

a. autocrine signaling 

Class I cytokines (hematopoietins, IL-2 family) use which family of tyrosine kinases to influence cell survival and proliferation

A. NFkappaB

B. JAK

C. Syk

D. TBK1

B. JAK

JAK/STAT signaling by cytokine receptors is often short-lived. What mechanism ensures this self-limitation?

a) Feedforward amplification via IRF7

b) Negative feedback via SOCS

c) Ligand scavenging via atypical receptors

d) Alteration of receptor subunit composition

b) Negative feedback via SOCS

Interferons are powerful antiviral cytokines. They are categorized as which class of cytokines?

a) Class I

b) Class Il

c) Chemokines

d) IL-1 family

b) Class Il

Type III interferon is molecularly most convergent with which of the following?

a) Type I IFN

b) Type II IFN

c) Hematopoietins

d) Chemokines

a) Type I IFN

The interferon-induced "antiviral state" depends on ISG effector functions. Which is a key mechanism of this state?

a) mRNA degradation

b) NF-KB activation

c) IL-1 secretion

d) Cytoskeletal reorganization

a) mRNA degradation

Chemokine families are divided into 4 distinct groups. What feature defines these families?

a) Spacing of N-terminal cysteines

b) JAK/STAT composition

c) Localization in distinct cellular compartments

d) Ability to activate G proteins

a) Spacing of N-terminal cysteines

Which of the following is NOT a chemokine receptor?

a) XCR1

b) CCR2

c) CXCRS

d) CLR1

d) CLR1

RIG-I like receptors (RLRs) are cytoplasmic sensors. What type of PAMP do they detect?

a) Viral RNA

b) Carbohydrates

c) Flagellin

d) Cytosolic DNA

a) Viral RNA

After detecting viral RNA, RLRs transmit signals through which adaptor molecule?

a) MAVS

b) MyD88

c) TRIF 

d) cGAMP

a) MAVS

Which of the following is a mechanical barrier that prevents microbial colonization of host tissues?

a) Lysozyme 

b) Tight junctions

c) Defensins 

d) Microbiome

b) Tight junctions

Defensins contribute to innate defense by:

a) Degrading bacterial peptidoglycans 

b) Blocking paracellular diffusion 

c) Disrupting microbial membranes

d) Outcompeting pathogenic flora 

c) Disrupting microbial membranes

The lectin pathway of complement is triggered by:

a) Antibody binding 

b) Carbohydrate binding 

c) Spontaneous activation 

d) C3 cleavage

b) Carbohydrate binding 

Which complement pathway begins spontaneously and can amplify the others?

a) Classical 

b) lectin

c) All of the above 

d)Alternative 

d)Alternative 

C3b plays an essential role in macrophage activation because it:

a) Functions as an opsonin

b) Forms pores in membranes 

c) Acts as an anaphylatoxin 

d) Signals through GPCRs 

a) Functions as an opsonin

The membrane attack complex (MAC) kills pathogens by:

a) Opsonization

b)Osmotic lysis 

c) Degranulation

d) Phagocytosis

b)Osmotic lysis 

Which complement fragments act as anaphylatoxins?

a) C3b, C5b 

b)C3a, C4a, C5a

c) C2a, C4b 

d) C7, C8, C9 

b)C3a, C4a, C5a

Phagocytosis links innate and adaptive immunity primarily through:

a) Granule release 

b) Antigen presentation

c) DAMP release

d) Complement activation

b) Antigen presentation

Which type of cell death is non-lytic and maintains membrane integrity?

a) Necrosis 

b) Apoptosis

c) Necroptosis

d) Pyroptosis

b) Apoptosis

Necroptotic cell death contributes to immunity by:

a) Bleb formation

b) DAMP release

c) Antigen presentation

d) Lysosomal fusion

b) DAMP release

Which property most clearly distinguishes adaptive immunity from innate immunity?

a) Fixed specificity

b) Rapid response

c) Somatic recombination

d) Barrier defense

c) Somatic recombination

Which best describes the relationship between antigens and antibodies?

a) Antigens are proteins produced by B cells 

b) Antigens are pathogen-derived targets for antibodies

c) Antibodies are pieces of pathogens recognized by T cells

d) Antibodies are used to present antigens to T cells

b) Antigens are pathogen-derived targets for antibodies

Which statement is TRUE regarding MHC-I and MHC-II expression?

a) MHC-I is found only on professional APCs

b) MHC-I is on all nucleated cells

c) MHC-II is found on all nucleated cells

d) MHC-II is absent from professional APCs

b) MHC-I is on all nucleated cells

Which T cell subset is activated by antigen presented via MHC-I?

a) CD4 helper T cells 

b) CD8 cytotoxic T cells

c) B cells

d) NK cells 

b) CD8 cytotoxic T cells

25. What is the primary effector function of CD8 T cells?

a) Antibody production 

b) Cytotoxic killing

c) Cytokine secretion

d) Antigen presentation 

b) Cytotoxic killing

26. Which cell type is the most potent antigen-presenting cell?

a) Neutrophil

b) Dendritic cell

c) NK cell

d) Plasma cell

b) Dendritic cell

27. Which granulocyte is most abundant in blood and specialized for phagocytosis?

a) Neutrophil

b) Eosinophil

c) Basophil

d) Mast cell

a) Neutrophil

28. Which cells can differentiate from monocytes after entering tissues?

a) Dendritic cells and macrophages

b) NK cells and B cells

c) Plasma cells and eosinophils

d) Mast cells and basophils

a) Dendritic cells and macrophages

29. In which tissue do naïve lymphocytes first encounter antigens that have drained from the interstitial fluid?

a) Thymus

b) Bone marrow

c) Lymph node

d) Peyer's patch

c) Lymph node

What feature is unique to the spleen as a secondary lymphoid organ?

a) It screens lymphatic fluid

b) It screens blood-borne antigens 

C It is a site of T cell development

d) It is a site of B cell development 

b) It screens blood-borne antigens 

Which of the following best distinguishes an antibody from a B cell receptor (BCR)?

a) Antibodies contain both heavy and light chains, while BCRs contain only heavy chains.

b) Antibodies are secreted, while BCRs are membrane-bound forms of the same molecule.

c) Antibodies bind antigen via covalent bonds, while BCRs use noncovalent interactions.

d) Antibodies are expressed only by naïve B cells, while BCRs are expressed by plasma cells.

b) Antibodies are secreted, while BCRs are membrane-bound forms of the same molecule.

32. Which immunoglobulin class is most rare in human serum?

a) IgE

b) IgG

c) IgA

d) IgD

a) IgE

33. IgM cannot do which of the following:

a) Bind Fcmu receptors

b) Initiate the classical complement pathway

g) Be expressed by naïve B cells

d) Cross epithelial barriers via the poly-Ig receptor

d) Cross epithelial barriers via the poly-Ig receptor

34. CD8 binds to which molecule?

a) MHC-llα chain

b) MHC-lα chain

c) ß2-microglobulin 

d) CD3zeta chain

b) MHC-lα chain

35. During BCR signaling, phosphorylated ITAMs on Iga and Igß recruit:

a) ZAP-70 

b) BLNK

c) Lyn

d) Syk

d) Syk

Which protein serves as a hub for TCR signalosome assembly?

a) LAT

b) BLNK

c) Lyn

d) Lck

a) LAT

37. Which feature increases the avidity of an antibody for its antigen?

a) The number of noncovalent bonds in each binding site

b) The total number of antigen-binding sites per antibody molecule

c) The complementarity of the variable regions

d) The presence of disulfide bonds linking heavy chains

b) The total number of antigen-binding sites per antibody molecule

38. Which immunoglobulin is most involved in promoting mucosal immune responses?

a) IgE

b) IgM

C) IgA

d) IgD

C) IgA

39. Which of the following correctly matches receptor and kinase in lymphocyte activation?

a) BCR - ZAP-70

b)TCR - Lyk

c) BCR - LAT

d) TCR - Syk

b)TCR - Lyk

40. Which region of an antibody determines its class (isotype)?

a) Variable region of the light chain

b) Constant region of the heavy chain 

c) Hinge region between Fab and Fc

d) CDR3 of the heavy chain

b) Constant region of the heavy chain 

41. The Fab portion of an antibody is most directly involved in:

a) Antigen recognition

b) Signal transduction within the B cell

c) Binding to Fc receptors on immune cells

d) Inducing class switch recombination

a) Antigen recognition

42. The protein BLNK is functionally most similar to which of the following?

a) TLR3

b) ZAP-70

c) MAVS

d) Lck

b) ZAP-70

43. How many types of light chains can a single immunoglobulin molecule contain?

a) One k and one lambda

b) Either k or lambda, but not both

c) One α and one beta

d) Either α or beta, but not both

b) Either k or lambda, but not both

44. Theoretical combinatorial diversity of human immunoglobulins is approximately:

a) 10^3

b) 10^6

c) 10^13

d) 10^15

c) 10^{13}

45. Which segments are present in heavy chains but not in light chains?

a) V segments

b) J segments

C) D segments

d) C segments

C) D segments

46. Which of the following products of somatic recombination does not contribute to junctional diversity?

a) Signal Joint

b) Coding joint

c) Random P nucleotides 

đ) Random N nucleotides

a) Signal Joint

47. P nucleotides are generated by:

a) AID-mediated deamination

b) TdT-mediated addition of random bases

c) Artemis-mediated hairpin opening

d) Exonuclease trimming

c) Artemis-mediated hairpin opening

N nucleotide addition is mediated by which enzyme?

a) RAG

b) TaT

c) Artemis

d) DNA ligase IV

b) TaT

49. Differential splicing of the u and & constant regions allows coexpression of:

a) IgA and IgG

b) IgE and IgA

C) IgM and IgD

d) IgM and Ige

C) IgM and IgD

50. Class switch recombination differs from alternative splicing because it:

a) Occurs at the RNA level

b) Permanently alters DNA

c) Occurs in naïve B cells

d) Does not affect constant regions

b) Permanently alters DNA

51. Which of the following permits TCRs to exhibit a higher degree of junctional diversity than Ig?

a) Decreased quantity of N nucleotides per junction

b) Increased TdT expression during recombination

c) Decreased chromatin condensation at the V segment

d) Increased degree of allelic exclusion

b) Increased TdT expression during recombination

52. Which heavy chain constant region is located immediately downstream of the VDJ segments?

a) gamma

b) mew

c) alpha

d) delta

b) mew

53. The a chain of the TCR resembles which part of the immunoglobulin?

a) Heavy chain

b) Light chain

c) Fc region

d) Constant domain

b) Light chain

54. Which process ensures that each B cell expresses receptors with a single antigen specificity?

a) Differential splicing

b) Allelic exclusion

c) Class switch recombination

d) Negative feedback inhibition

b) Allelic exclusion

55. Which statement about TCR a chains is TRUE?

a) TdT expression is high during a chain recombination.

b) T cells can sometimes express two distinct a chains.

c) The a chain contains D segments.

d) The a chain rearranges before the ß chain.

b) T cells can sometimes express two distinct a chains.

56. Junctional diversity affects protein structure in which of the following regions:

a) CDR1 in Ig; CDR1 in TCR

b) CDR1 in Ig; CDR3 in TCR

c) CDR3 in Ig; CDR1 in TCR

d) CDR3 in Ig; CDR3 in TCR

d) CDR3 in Ig; CDR3 in TCR

57. Which of the following statements about class switch recombination (CSR) is correct?

a) It affects the variable region of the antibody.

b) It alters antigen specificity.

c) It changes the Ig constant region to modify effector function.

d) It is reversible after cell division.

c) It changes the Ig constant region to modify effector function.

58. What molecular event initiates DNA double-stranded breaks in switch regions during CSR?

a) AID converts cytidine to uracil

b) TdT adds random nucleotides

C) RAG cleaves RSS sequences

d) Artemis opens hairpin loops

a) AID converts cytidine to uracil

59. How do cytokines influence B cell class switching?

a) They promote transcription at the switch region of the target isotype

b) They induce recombination of VDJ segments

c) They enhance allelic exclusion

d) They enhance expression of TdT

a) They promote transcription at the switch region of the target isotype

Which of the following immunoglobulin regions induce effector functions?

a) Variable region

b) Fab region

c) Fc region

d) N terminus

c) Fc region

61. Which of the following determines whether an immunoglobulin transcript becomes a secreted antibody or a B cell receptor?

a) Differential mRNA splicing

b) Class switch recombination

c) Somatic hypermutation

d) Antigen specificity

a) Differential mRNA splicing

62. Which of the following determines overall strength of interaction between immunoglobulin and target antigens?

a) Affinity and stability

b) Affinity and avidity 

c) Specificity and stability

d) Specificity and avidity

b) Affinity and avidity 

63. Which of the following is the correct order for recombination of the TCR alpha chain?

a) V and J segments are combined, then constant region

b) V and J segments are combined, then D segment, then constant region

c)D and J segments are combined, then constant region

d)D and J segments are combined, then V segment, then constant region

a) V and J segments are combined, then constant region

64. Which of the following antibody isotypes can serve as opsonins to induce phagocytosis?

a) IgG and IgA

b) IgG and IgM

8) IgM and IgD

d) All isotypes

a) IgG and IgA

65. Which of the following antibody isotypes can initiate the classical complement pathway?

a) IgG and IgA

b) IgG and IgM

c) IgM and Igb

d) All isotypes

b) IgG and IgM

​​66. Which of the following immunoglobulin isotypes is made during a Type 2 response to parasitic infection?

a) IgM

b) IgG 

C)IgE

d) IgA

c) IgE

67. Which of the following reflects the subunit structure of MНC-1?

a) Va, Ca, VB, CB

b) a1, a2, a3, B2-microglobulin

c) al, a2, B1, B2

d) VH, CH1, CH2, CH3

b) a1, a2, a3, B2-microglobulin

68. Which of the following does not constitute part of a possible immunological synapse?

a) MHC-I, TCR, CD3

b) MHC-I, TCR, CD8

c) MHC-II, TCR, CD3

d) MHC-II, TCR, CD8

d) MHC-II, TCR, CD8

69. Which of the following proteins is responsible for phosphorylation of ITAMs on the B cell receptor complex?

a) Lyn

b) Lck

c) Syk

d) ZAP-70

a) Lyn

70. Which of the following proteins is a Syk family kinase involved in T cell signal transduction?

a) Lyn

b) Lck

c) Syk

d) ZAP-70

d) ZAP-70

71. Which of the following is an adaptor protein involved in B cell signal transduction?

a) Lyn

b) Syk

C)BLNK

d) LAT

C)BLNK

Which of the following proteins does not have intrinsic catalytic activity?

a) Lyn

b) LCK

c) ZAP-70

d) LAT

d) LAT

73. Which of the following roles are directly performed by Src family kinases?

a) Antigen recognition

b) Phosphorylation of ITAMs

c) Phosphory lation of Syk family kinases

d) Formation of signalosomes

b) Phosphorylation of ITAMs

74. Which of the following is the correct order of genetic events resulting in the formation and expression of immunoglobulin genes from germline DNA?

a) Transcription, splicing, translation, somatic recombination

b) Transcription, somatic recombination, splicing, translation

c) Somatic recombination, transcription, splicing, translation

d) Splicing, somatic recombination, transcription, translation

c) Somatic recombination, transcription, splicing, translation

75. Ig variable domains are encoded by discrete gene segments. Ig light chains are encoded by ___ segments and Ig heavy chains are encoded by ___ segments.

a) V and J; V and J

b)V and J; V, D, and J

c) V, D, and J; V and J 

d) V, D, and J; V, D, and J

b)V and J; V, D, and J

76. Which of the following is the correct order for recombination of the Ig heavy chain?

a)V and J segments are combined, then constant region

b) V and J segments are combined, then D segment, then constant region

C)D and J segments are combined, then constant region and 

d) D and J segments are combined, then V segment, then constant region

d) D and J segments are combined, then V segment, then constant region

77. Which of the following proteins facilitates synapsis and cleavage of gene segments during somatic recombination?

a) DNA-PK

b) Artemis

C) RAG

d) TdT

C) RAG