Questions and Actual Answers (2025-
2026) Updated Set.
Where do B and T lymphocytes originate? - Answer bone marrow
What characterizes the pre-B-cell stage in B-cell development? - Answer -expression of the
pre-BCR
-rearrangement of light chain genes
-proliferation
What characterizes the pro-B-cell stage in B-cell development? - Answer commitment to the
B-cell lineage
How does allelic exclusion prevent multiple heavy-chain rearrangements from occurring in pre-B
cells? - Answer RAG1 and RAG2 are downregulated, and TdT activity is lost so that no
additional heavy-chain rearrangements may take place
At what stage of development does a B cell begin to express a pre-B-cell receptor? - Answer
late pre-B cell
How long does B-cell maturation from an HSC to a mature B cell take? - Answer 1-2 weeks
All of the following are true regarding B-cell development - Answer -B cells are mostly
developed when they leave the bone marrow
-Self-reactive B cells may be eliminated though apoptosis
-Self-reactive B cells may be rendered unreactive (anergic)
-B cells complete maturation in the spleen
-B cells, unlike like T cells, are not MHC class restricted
V-DJ recombination occurs during which phase of a B cell's development? - Answer pro-B cell
, What is the final step of the V(D)J recombination process? - Answer ligation by DNA ligase IV
and NHEJ proteins
V-J rearrangement occurs in - Answer both B and T cells
Mature naïve B cells express high levels of _____ on their cell surfaces - Answer IgD
You have consumed a salad contaminated with Salmonella enterica, which typically causes a
self-limiting, gastrointestinal disease in humans. Based on this information, which immune
organ is MOST likely to first recognize and mount a response against the pathogen? - Answer
GALT
If a human were unable to produce lymphoid progenitor cells, predict which part of the immune
system would be MOST greatly impacted? - Answer adaptive immunity
Consider the following statement from the text, "Immunologists had to face the fact that there
simply was not enough DNA to encode all the relevant B-cell receptors, using the one-gene,
one-polypeptide chain rule." What does this statement mean? - Answer It would take more
DNA to encode for all the possible B-cell receptors that can be expressed than the amount of
DNA present in the human genome
Do you think the statement that 'all human cells in an individual contain the same genome' is
true or false? - Answer False. Upon completing V(D)J recombination, individual B-cells ready to
respond to antigen contain unique regions within their genomes that, in turn, encode for
unique antibodies.
What introduces single-strand break between V(D)J coding sequence and heptamer RSS? -
Answer RAG 1/2
Deficiency in RAG1 and/or RAG2 can affect the proper development of which of the following
cell types, resulting in decreased numbers of circulating cells of those types? - Answer B cells
and T cells
What does the RAG 1/2 enzyme complex bind to at the start of the V(D)J recombination
process? - Answer RSS