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19 Cards in this Set
- Front
- Back
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Host Defense: Acquired, specific
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Third line of defense. * B & T lymphocytes, antibodies, cytotoxicity - This includes specific host defenses that must be developed uniquely for each microbe through the action of specialized white blood cells. This form of immunity is marked by its activity toward specific pathogens and development of memory. |
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White Blood Cells: Lymphoid >> Lymphoblasts |
Agranulocytes T & B Lymphocytes: primary cells involved in specific immune reactions to foreign material.
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T cells
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Perform a number of specific immune responses such as assisting B cells and cell-mediated immunity. |
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B cells
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Differentiate into plasma cells and form antibodies (humoral immunity)
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Natural Killer (NK) cells
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Related to T cells but displaying no specificity; active against cancerous and virally infected cells.
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Specific Immunity: Adaptive Line of Defense *** Third line of defense acquired for long term protection. - Dual system of T & B lymphocytes. |
* developed through infections, vaccinations, fetal development.
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Immunocompetence |
During fetal development, lymphocytes undergo a selective process that prepares them for reacting only to one specific antigen. *** Immunocompetence: during this time, there is the ability of the body to react with a wide spectrum of foreign substances begins to develop. *** An infant is born with the theoretical potential to produce an immune response to millions of different foreign molecules and antigens. Immunocompetence takes years to complete, extending into puberty. **** Every time exposed, there is a response - refines till end of life. |
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Antigen
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Any molecule that can stimulate a response by T and B cells. * Proteins, polysaccharides, and other compounds from cells and viruses, as well as environmental chemicals - actually, any exposed or released substances is potentially an antigen -- even those from our own cells. |
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Two features that characterize specific immunity and differentiate it from the innate immunity:
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* Specificity - Antibodies produced, function only against the antigen that they were produced in response to * Memory - lymphocytes are programmed to "recall" their first encounter with antigen and respond rapidly to subsequent encounters. |
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*** pg 457! 1) Development of Lymphocyte System: |
Lymphocytes arise from the same stem cells but differentiate into two distinct cell types early on. B cells mature in specialized bone marrow sites, and T cells mature in the thymus gland. Mature cells settle in lymphoid organs and serve as a constant attack force for infectious agents.
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- continued- Lymphocyte stem cell maturation |
B cell line: special bone marrow sites T-cell Line: Thymus * Migration to and establishment of B and T cells in lymphoid organs such as lymph nodes, spleen and MALT. (Mucosal affiliated Lymphoid Tissue) |
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2) Contact with Antigen and 3) Presentation by Antigen presenting Cells (APC's)
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Foreign cells bear molecules (antigens) that are recognized and engulfed by APC's such as dendritic cells. For most responses, T helper cells first receive the processed antigen from the APC and go on to activate B and other T cells. |
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2) Antigen contact
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Most B-cells require activation by helper T cells.
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3) Dendritic cell displays antigen and presents it to T helper cell
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T helper cells activates most of B cells. ** In this case complex antigen is process by the phagocytic cell, the dendritic cell. |
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4A) B-cell responses.
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* A B-cell activated by T helper cells undergoes a spurt of cell division, producing memory cells that provide a rapid recall of antigen, and plasma cells that secrete proteins called antibodies. |
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4A) Activated B cell
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activates memory B-cells and Plasma cells |
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4B) Humoral Immunity
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Antibodies circulated in fluids (blood, ECF (extracellular fluid), and lymph) providing humoral immunity . The antibodies react specifically with antigen and mark it for an enhanced response. * Memory B-cells and Plasma cells secrete antibodies into bloodstream Humoral Immunity |
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Cell Mediated Immunity 5A) Activation of T Cells (to naive T cell) |
Activated T cell > Memory T-cells Or Activated T-cells release Cytokines > Develop receptors that differentiate them into * Helper T-cells or * Cytotoxic T-cells |
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Cell mediated Immunity 5B) T-cell Responses |
Activated T-cells release Cytokines > Develop receptors that differentiate them into * Helper T-cells or * Cytotoxic T-cells |
