Bio exam module 3 and 4

What finding of Heidelberger and Avery helped determine that antibodies are proteins? 

The antibody component of the precipitate contained nitrogen 

True or false: If you receive an antiserum for a pathogen from an immunized individual, you are immune to the pathogen for life.

False

Fill in the blank: Antibodies are ____.

Gamma-globulins

What ratio of IgH and IgL results from disulfide bond reduction?

1:1

What two proteins are associated with surface IgG that have ITAMs on their cytoplasmic tails?

Igα ,Igβ 

True or false: The light chain contains the transmembrane region anchoring a BCR into the cell membrane.

False

Which domain(s) make up the antigen-binding region?

Variable light domain and Variable heavy domain

Which of the following portions of an antibody recognizes antigen?

CDR

Which of the following is not an antibody effector function? I. Activating NK cell ADCC II. Enhancing eosinophil phagocytosis III. Toxin neutralization

II only

Which would you expect to have higher avidity for antigen: IgM expressed as a BCR, or IgM in soluble form?

IgM in soluble form

What most influences the binding strength between a BCR and its ligand?

Receptor valency

What antibody characteristic allows antibody-bound molecules to be precipitated out of solution?

Their multivalency 

How are polyclonal antibodies generated?

By normal in vivo immune responses 

Why were Susumu Tonegawa’s experiments so significant?

They showed that B cells recombined their DNA to form their antigen receptor 

All of the following statements regarding antibody heavy and light chains are true except:

CDR3 regions are found in the constant region

Both contain variable and constant regions 

The heavy chain variable region contains V, D, and J gene segments 

Constant regions are made of one of only a few gene sequences

CDR3 regions are found in the constant region

What is the purpose of the heavy chain constant region? 

Determines antibody effector function 

The CDR3 region is made of: 

The joint between gene segments of the heavy and light chains 

Which of the following are mechanisms contributing to the diversity of the naive B cell repertoire?
    I. Each heavy chain can pair with a different light chain, and vice versa

   II. Multiple gene segments at heavy and light chain constant region loci 

  III. Templated nucleotide addition during V(D)J recombination

I only

Which of the following are functions of RSSs? 

I. Flank Ig gene segments for recognition by RAG proteins

II. Assist Ku70/80 proteins in cutting intervening regions of DNA

III. Aid Artemis in ligating the coding ends together

I only

What would be a consequence of a TdT gene mutation that renders the enzyme non-functional?

A lack of diversity would be seen in the V regions of BCRs

Which of the following statements regarding coding joints is true?

Coding joints are excised during recombination

Coding joints are inverted during recombination

Coding joints are found only in the heavy chain

Coding joints are where TdT adds N-nucleotides

Coding joints are where TdT adds N-nucleotides

Exonuclease trimming at V(D)J joints can result in an unproductive rearrangement. Why?

It can cause loss of the correct transcriptional reading frame

Where does embryonic B cell development occur? 

Fetal liver 

Which Ig gene rearrangements occur first during B cell development? 

V_H-D_H

D_H-J_H

V_H-J_H

V_L-J_L

D_H-J_H

The surrogate light chain of the pre-BCR is composed of: 

VpreB and 𝛌5

Why does successful pre-BCR signaling induce down-regulation of RAG1/2?

To prevent further heavy-chain recombination from occurring

What occurs following initial membrane IgM expression on a developing B cell? 

B cell is tested for self-reactivity via negative selection 

True or false: In general, the CDR2 region of a TCR makes the most contact with peptide bound to MHC.

False

Which of the following is true?

γδ TCRs directly transduce signals  into the cell
γδ TCRs directly transduce signals  into the cell

TCRs undergo isotype switching 

TCRs are made of immunoglobulin domains

TCRs are made of immunoglobulin domains

Which of the following is NOT part of the CD3 signaling complex?

CD3 zeta

CD3 alpha 

CD3 delta

CD3 epsilon 

CD3 alpha 

Presence of which of the following allows TCR and BCR signaling proteins to transduce signals into the cell?

ITAMs

True or false: Unlike BCRs and antibodies, TCRs only have one antigen binding site.

True

Which TCR genes are located within the TCRα loci? 

δ 

True or false: V-D-J gene segments recombine to form the TCRβ chain and V-J gene segments recombine to form the TCRα chain.

True

Polygenic refers to: 

Genes that code for proteins with the same function, but possess different structures

Which of the following could directly induce conversion of a normal proteasome to an immunoproteasome? 

Cytokines like IFN-γ or TNF

Lack of HLA-DM would result in: 

Low affinity peptides binding to MHC II

Which process results in endogenous (intracellular) antigen presentation on MHC class I? 

Macroautophagy

Chaperone-mediated autophagy

Cross-presentation

None of the above 

None of the above 

What role do CD4 and CD8 proteins play in the immune response?

They bind MHC to enhance TCR:MHC interactions

What is the key signal for common lymphoid progenitors to commit to the T cell lineage

Notch

At what stage of T cell development is the pre-TCRa expressed?

DN3

Which cells do T cells interact with to test recognition of MHC during positive selection?

cTEC

Which model of lineage commitment most likely is correct?

Kinetic signaling model

During negative selection, what are the possible fates of T cells that recognize antigen/MHC on mTECs too strongly?

Proliferation

Apoptosis

Natural treg generation

Both B and C