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12 Cards in this Set
- Front
- Back
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Define B-lymphocytes
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B-lymphocytes are responsible for the humoral immune response.
-Mature in Bone marrow -They interact with antigens encountered in the circulation. |
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Define T-lymphocytes
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T-lymphocytes are responsible for cell-mediated response.
-Mature in the Thymus -They interact with antigens presented by other cells |
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What is an epitope?
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An epitope is the molecular shape of foreign molecules that are recognizable by the immune system
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What is an antigen?
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An antigen (antibody generator) is a substance that can elicit an immune response.
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What are Immunoglobulins?
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IG's are circulating antibody molecules secreted by the B-lymphocytes.
IG's make up about 20% of the proteins in the blood plasma. |
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Describe the clonal-selection theory for production of specific antibodies.
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1.Many B-cell receptors already exist in the cell.
2.Some of the millions of B-lymphocyte types will recognize Epitopes of the antigen 3.The few that recognize it will divide to produce many more to aid in fighting the antigen. Also many will be placed in reservoirs in the lymph nodes so they can quickly come back |
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Describe the formation of a light chain polypeptide.
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-Recombinase links one V segment and one J segment, eliminating the long stretch of DNA between them.
-Transcription results in the formation of the functional gene. (V3-J5-Intron-C region) -RNA processing removes the intron. -It is then translated into the variable and constant region (V-C) found on Ig's |
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What is the difference between the primary immune response and secondary immune response?
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-The primary immune response is the reaction from the body to a particular antigen it has never been exposed to before. (10-17 days response time)
-The secondary immune response is the reaction to an antigen the body has already seen. (2-7days) |
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What are the 3 major classes of Ig's in the notes.
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IgM-(10% of Ig's) Tend to be involved with agglutination.
IgG-(75%) Do the major work of humoral immunity IgE-(<1%) Stem binds to surface of mast cells causing release of histamine. |
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Explain the steps of the Humoral immune response.
-Helper T cell -Macrophage -Class II MHC -B cell |
1. A macrophage engulfs and degrades a bacterium. It displays the bacteria's antigen w/ a class II MHC.
-The helper T cell that recognizes it is ACTIVATED and replicates. 2. This T cell will bind to a B cell that has taken up the same bacterium. This ACTIVATES the B cell 3. The B cells then differentiate into memory B cells and the others secrete the harmful bacterium. |
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Explain the killing action of cytotoxic T cells.
-Cytotoxic T cells -Class I MHC CD8 -Granzymes -Apoptosis (kill itself) |
1. A cytotoxic T cell binds to a class I MHC-antigen complex on a target cell w/ the aid of CD8.
2. The activated T cell releases molecules, which form pores in the target cell membrane. 3. The granzymes released by the T cell initiate apoptosis in the target cell. Which causes it to die. |
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What is the basis for infection of HIV.
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The major HIV envelope glycoprotein, GP-120, specifically recognizes and binds to the CD4 surface molecule, the molecular trademark of helper T cells and makes them useless.
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