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28 Cards in this Set
- Front
- Back
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What is the main difference between the humoral and cellular immune responses? |
The humoral response is when B cells, etc. target to eliminate free-floating antigens in the blood/plasma; the cellular immune response is when infected host cells are targeted for destruction |
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Describe the main difference between the primary and secondary immune responses. |
The secondary immune response, i.e. when the body is exposed to the same antigen for the second time, releases almost double the amount of antibodies upon second-time exposure to the antigen than it did the first time it was exposed to the antigen. |
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A incredibly large diversity of B cell lymphocytes exists, and each is equipped with its own antigen-specific receptor. What happens if an antigen engages a receptor that it fits? |
The lymphocyte will expand clonally to overwhelm and target the antigen |
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The basic molecule of the immune system's humoral response is the... |
Antibody |
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What secretes antibodies? |
Stimulated B cells |
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T/F: Antibodies are also produced as a membrane-bound form on unstimulated B cells. |
True |
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What is the most common form of secreted antibody? Describe its structure and where the antigen binds on it. |
IgG; two heavy and two light chains, and the antigen binding site is comprised of portions from both chains |
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Describe IgG real quick, and its processions by papain. |
Light chains on top (Vl and then Cl), and Heavy chains on bottom (VH, CH1-3 on each side). Papain splits before the V of the Y, leaving CH2 and CH3 on each heavy chain alone |
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What chain changes in different types of antibodies? |
The Heavy chain |
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Function of Ig... A? |
Tears, sweat, and mother's milk |
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Function of Ig... E? |
Allergies |
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Function of Ig... M? |
First antigen to respond |
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Function of Ig... G? |
Most common, only Ig to cross the placenta
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Common Ig fold? |
4 and 3-stranded antiparallel beta pleated sheets |
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Common antigen binding site on Ig? |
CDR1-3, found on the H and L chain variable regions |
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T/F: The conformation in the antibody hypervariable loops are the segments most different between antibody molecules. |
True
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What are the 2 theories explaining the diversity of antibody responses? |
Germline (many genes expressed as needed upon antigen exposure) Somatic (recombination - antibody diversity generated by recombination; mutation " " by Ig gene mutation during B cell differentiation) |
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Formation of the light chain involves recombination of what segments in DNA? Then brought to the ER by what? |
V and J segments; brought to ER by (L) leader peptide |
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What DNA structure aids in the recombination of V and J genes for light chain diversity? What other genes help this? |
The cruciform DNA conformation, HLHl RAG1 and RAG2 (recombination-activating genes) also aid in this |
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T/F: VJ recombination is not precise which leads to another form of diversity. |
True |
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Name the 4 ways in which VJ recombination is different in forming heavy chains. |
There is another element, D Many exons N regions are randomly added bps between recombination junctions D/J goes first, then V/DJ |
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What must be present in the DNA in order for all of this rearrangment to occur? |
RSS (recombination signal sequence) |
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Describe the composition of gene-flanking RSSs. |
Heptamer, 12bp spacer, nonamer ------(intervening DNA)----- nonamer, 23bp spacer, heptamer |
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T/F: The conversion of IgM from a membrane-bound to asoluble form occurs via analternative splicing eventperformed at the RNA level. |
True |
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T/F: Like Light and Heavy Chain Diversity, Class Switching Is alsoMediated by DNA Recombination. |
True |
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How are T cells different from B cells, even though they have V and C domains and benefit from the diversity brought about by VDJ recombination events? |
They are specific for certain presented antigens AND the MHC proteins that bind and deliver these antigens to the cell |
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What is the difference between MHC I and II, both part of the Ig superfamily? |
I brings antigens to killer T cells, II brings antigens to helper T cells |
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What do killer and helper T cells express differently? How does this relate to HIV's MoA? |
Killer - CD8 Helper - CD4 HIV recognizes CD4 and blocks its ability to initiate cellular immune responses |
