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Cards In This Set
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15.01 Describe how the 3rd line of defense differs from the other lines of defense?
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Specificity and Memory
When host barriers and nonspecific defenses fail to control an infectious agent, a person with a normally functioning immune system has a mechaism to resist the pathogen- this 3rd, SPECIFIC line of immunity.
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15.02 List the 4 stages of a specific immune response?
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1. Lymphocyte development
2. Presentation of antigens
3. Activation of lymphocytes/clonal expansion
4. Antibody production/cell-mediated immunity
B cells: antibody production
T cells: cell-mediated immunity
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15.04 Describe the major histocompatibily complex (MHC) in 2 sentences.
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The MHC is a set of genes that codes for human cell receptors that give rise to a series of glycoproteins (found on all cells except red blood cells). This marker complex plays a vital role in recognition of "self" by the immune system, and in rejection of foreign tissues.
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15.05 Contrast the way T cells recognize antigen with the way B cells do?
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Both B and T cells have protein receptors that bind to antigen.
B cells: can combine with the antigen directly
T cells: cannot recognize antigen unless coupled with a "self" marker
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15.07 Explain how our bodies are equipped with lymphocytes capable of responding to nearly any antigen imaginable?
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Lymphocytes are thought to use 500 gene segments to produce a vast array of specific antigen receptors. Early lymphocytes undergo a series of divisions and genetic changes that generate hundreds of millions of different B and T cells (each carrying specific receptor regions). By the time B and T cells enter the lymphoid tissues, each is equipped to respond to a single, unique antigen.
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15.08 Outline the processes of clonal selection and expansion?
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When a foreign antigen enters the immune surveilance system, it encounters specific lymphocytes ready to recognize it. This contact stimulates that "clone" to undergo mitotic divisions to create more antigen-specific clones.
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15.09 Describe the B cell receptor and the T cell receptor.
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B cell receptor is an immunoglobulin (Ig) molecule, large glycoprotein molecules with 4 polypeptide chains in a forked shape.
T cell receptors are relatively small, and is never secreted.
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15.10 Compare the terms antigen, immunogen, and epitope?
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Antigen/Immunogen: any cell, particle, or chemical that induces a specific immune response by B or T cells
Epitope: the precise molecular group of an antigen that defines its specificity and triggers the immune response
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15.12 List the types of cells that can act as antigen-presenting cells?
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APC's antigen-presenting cells
1. Macrophages
2. B cells
3. Dendritic cells
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15.18 List the 3 major types of cells that T cells can differentiate into after stimulation?
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Helper T cells
Regulatory T cells
Cytotoxic T cells
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15.19 Describe the main functions of the 3 types of T cells?
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Helper T cells- activate macrophages, assist B cell processes, and activate cytotoxic T cells
Regulatory T cells- control the T cell response (dampens immune response)
Cytotoxic T cells- lead to teh destruction of infected host cells and other foreign cells
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15.20 Explain how TC cells kill other cells.
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Usually bears a CD8 cell, that once activated, the Tc cell recognizes the infected "self" and perforins punch holes in the cell membrane and granzymes enters infected cell inducing death.
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