Exam Two Flashcards
Which type of mature B cell responds to a protein antigen?
B-2 B cells and MZ B cells
V-D-J rearrangement occurs in___________
B cells and T cells
True or False: Kappa and lambda light genes are located on the same chromosome.
FALSE
Which TCR gene variable regions possess a “J” segment?
alpha, beta, and gamma
If you stain DCs with TAP1 antibody, which intracellular compartment would exhibit positive?
Rough Endoplasmic Reticulum, or Rough ER
Which of the following cell types would be LEAST likely to express MHC class II? A. Mast cells B. B cells C. Dendritic cells D. Macrophages
Mast cells
True or False: MHC polymorphisms occur in the peptide-binding groove
TRUE
Activated membrane-bound IgM or secreted IgM is determined by _____
alternative splicing of pre-mRNA
What happens when HSC is cultured in the presence of Notch ligand?
The HSC differentiates into T cells rather than B cells.
BCR and TCR VDJ recombination is an event occurring at what level?
the DNA level
True or False: Anchor residues at both ends of the peptides on MHC class I molecules
TRUE
What kind of diversity do mature B-1 cells show in their V-region?
High or low, depending on the active infection
Where do T-lymphocyte progenitors originate?
Bone marrow
What is only expressed in the loci of Ig heavy chain?
D (diverse)
If you have an HLA a/b MHC haplotype and 2 siblings, your chances of having the identical haplotype as your sibling are
1:4
What kind of signal do cells need to survive during positive selection?
intermediate signal
Where are B lymphocytes generated in? Where do they further mature?
Bone marrow | spleen
True or False: T cells can recognize MHC molecules
TRUE
What happens to autoreactive cells that escape the thymus?
They attack self-tissues
What is the most developed type of B cell?
Pro-B cell
When thymocytes interact with MHC II to generate a continuous signal, what cell type is then generated?
CD4+ T cells
Which TCR gene variable region possesses a “D” segment?
δ
Which is the most abundant light chain of an antibody in mice?
Kappa
What is T cell self-MHC restriction?
This is when a T-cell clone only recognizes foreign peptides when presented by self-MHC
True or False: B cells, like T cells, are MHC class restricted.
FALSE
What is the function of a CD1 cell?
display lipid antigens
What is the function of a CD3 cell?
T cell coreceptor complex
What is the function of a MHC class I cell?
binds to CD8 TCR
What is the function of a MHC class II cell?
binds to CD4 TCR
What is the function of a Treg cell?
regulate APC cell antigen presentation
Which MHC has peptide-binding domain alpha1/beta1?
MHC II
Which MHC has peptide-binding domain alpha1/alpha2
MHC I
Positive selection…
…results in self-MHC restriction
Negative selection…
…ensures self-tolerance
TNF family cytokines are found in…
MHC III
Allelic exclusion
the mechanism that ensures only one heavy-and-light-chain allele are transcribed and translated from a B cell
Professional APCs
These antigen-presenting cells are specifically MHC class II-expressing cells, including DCs, macrophages, and B cells.
Clonal anergy
A method of self-tolerance where autoreactive T cells are inactivated through negative selection
Receptor editing
the reactivation of recombination machinery on autoreactive receptors in light chains
mRNA splicing
the cause of IgM and IgD antibodies being expressed by mature B cells. Controls whether membrane-bound or secreted IgM is produced by removing the intervening spacer between the VDJ and C regions
Cross-presentation
The presentation of exogenous antigens on MHC Class I molecules (mainly DCs) to CD8 T cells.
Homozygous
having the same alleles at a particular gene locus on homologous chromosomes
RSS “12/23 Rule”
The rule that a 12 bp recombination signal sequence (RSS) must pair with a 23 bp RSS for V(D)J recombination to occur
Self-tolerance
The ability for the immune system to recognize and allow for self-produced antigens while avoiding autoimmune diseases from developing. Examples include clonal deletion, arrest, anergy, and editing.
Describe the five mechanisms that generate BCR diversity in naïve B cells.
- Multiple gene segments that can vary in order
- Templated P nucleotide addition between joints from asymmetrical cleaving of hairpin structures
- Exonuclease trimming that results in losing nucleotides and changing reading frames
- Non-templated N nucleotide addition that adds in random nucleotides between joints
- Diversity generated with the way in which heavy chains pair with varying light chains
Describe the major steps of class I Endogenous pathway presentation.
Peptides, generated by proteasomes, are transported from the cytosol to the rough endoplasmic reticulum (RER) where TAP molecules move the fragments. At this point, MHC class I molecules from RER ribosomes anchor in the RER membrane after their translation.
Describe the models that may regulate T cell lineage (SP T cell) commitment.
Instructive model: The co-engagement of TCR/CD4 and TCR/CD8 generate signals that instruct T cells which lineage to fully commit to
Stochastic model: Positively-selected thymocytes randomly down-regulate CD4/CD8 with only those with the “correct” coreceptor receiving the signal to continue development
Kinetic signaling model: This model has two branches: Cells committing to the CD4 lineage if they receive a continuous signal, or committing to CD8 lineage of the stimulation signal is interrupted
