Lecture 9: Oncology Flashcards
What must B and T cells be able to recognize?
a wide variety of antigens (diversity)
What allows for even more diversity in B and T cells?
Somatic mutation
How are surface immunoglobulin and T-cell receptors structurally similar?
Heterodimer proteins, disulfide bonds, have variable (V) and constant (C) regions
How are surface immunoglobulin and T-cell receptors genetically similar?
Have large number of exons DNA recombination to functional receptor
Surface Immunoglobulin and T-cell receptors are involved in what process?
antigen recognition (by normal B & T-cells)
For DNA recombination in B and T cells what are the segments that can be transcribed and translated to millions of antigen receptors?
V, D, J, and C
What can increase the sensitivity of T cells to peptide antigen MHC complexes by ~100 fold?
CD4 and CD8
What are gene rearrangements?
normal events, can occur in lymphocytes
What are the classes of immunoglobulins?
IgG, IgD, IgA, IgM, and IgE respectively
What are the immunoglobulin light chain genes?
k, λ (kappa and lambda)
What are immunoglobulin light chain genes encodes by?
immunoglobulin kappa and lamnda
Does rearrangement in each cells occur independently? or dependently?
independently
What genes rearrange?
T-cell receptor genes (α, β, γ, δ) rearrange
What defines the classes of immunoglobulins?
Antibody genes immunoglobulin heavy chain genes IgH (γ, δ, α, μ, ε)
What is the variable domain of heavy chain made of?
three segments (V, D, & J)
What residues does VH genes encodes?
residues 1-94
What residues does JK encode?
residues 98-113
What residues does D gene encode?
residues 95-97
51 V x 27 D x 6 J =8262 ???
Heavy chain??? idk about this one
Sarahboo it’s 8262 different combinations silly
What do heavy and light Ig chains undergo?
random gene rearrangement
TCR rearrangement vs. Ig rearrangement
they are VERY similar
What are the 7 means of generating antibody diversity?
- Multiple germ-line gene segments
- Combinatorial V-(D)-J- joining
- Junctional flexibility
- P-region nucleotide addition (P-addition)
- N-region nucleotide addition (N-addition)
- Somatic hypermutation
- Combinatorial association of light and
heavy chains
Population of cells with similar characteristics that are all derived from a single precursor cell
clonality
Normal lymphocyte populations are ____ with respect to Ig and TCR genes
polyclonal
Leukemia or lymphoma is ______ with regard to Ig or TCR rearranged genes
monoclonal
Neoplastic transformation of B and T lymphocytes occurs at different stages of B-cells and T-cell development at which the disordered lymphoid cells ______ in the normal differentiation scheme
arrested
B lymphocyte: Benign (Clonality of Lymphoid Proliferation Disorder)
Ig Light Chain, Heterogeneity
Plasma Cells: Benign (Clonality of Lymphoid Proliferation Disorder)
Heterogeneous Ig Electrophoresis
T Lymphocyte: Benign (Clonality of Lymphoid Proliferation Disorder)
Heterogeneous Variable Regions
B lymphocyte: Malignant (Clonality of Lymphoid Proliferation Disorder)
Ig Kappa or Lambda Only
Plasma Cells: Malignant (Clonality of Lymphoid Proliferation Disorder)
Monoclonal Ig Spike
T Lymphocyte: Malignant (Clonality of Lymphoid Proliferation Disorder)
Homogeneous Variable Regions
What is tumor cell clonality caused by?
gene rearrangement
Are rearrangements unique in each cell?
yes
What do rearrangements display?
allelic exlusion
Techniques for Clonality Determination
Morphology
Immunopathology
Cytogenetics
Molecular genetics
What is Morphology?
Monomorphous cell population
What is Immunopathology?
Monotypic Sig
What is Cytogenetics?
Recurrent chromosomal alteration (e.g., translocation)
What is Molecular genetics?
Clonal B- or T-cell gene rearrangements methods
What are all the clonal B- or T-cell gene rearrangements methods?
-Hybridization, blotting
-Standard PCR, RT-PCR, electrophoresis
-PCR with heteroduplex analysis, SSCP
-Real-time PCR with gene or patient-specific probes
What is an increasingly popular method to evaluate for the presence of B- or T cell clonality?
Polymerase Chain Reaction