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21 Cards in this Set
- Front
- Back
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The adaptive immune response is limited to ___________________? |
jawed vertebrates |
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What is an antigen? |
-any macromolecule that activates B or T lymphocytes -an "antigen" is to the adaptive immune response what a "PAMP" is to the innate immune response |
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What are some differences between B cells and T cells? |
-T cells require antigen presentation by dedicated APCs whereas the BCR directly recognize its cognate antigen -T cells recognize 2D, or linear, antigens whereas B cells recognize 3D antigens |
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What are the 2 forms of adaptive immunity? |
1. Humoral Immunity 2. Cellular Immunity |
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What is Humoral Immunity? |
-type of adaptive immunity -directed against extracellular microbes -mediated by B cells which secrete antibodies that neutralize and eliminate microbes and microbial toxins |
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What is Cellular Immunity? |
-type of adaptive immunity -directed against intracellular microbes -mediated by T cells which activate phagocytosis and lymphocytes or kill infected host cells |
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What are the 5 phases of the adaptive immune response? |
1. Recognition 2. Activation 3. Effector Phase 4. Decline 5. Memory |
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What happens in the activation phase of the adaptive immune response? Does it require anything? |
-lymphocytes differentiate and start clonal expansion -activation requires 2 signals: antigen receptor binds antigen (1) and microbial or innate immune signals (2) |
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What happens in the effector phase of the adaptive immune response? |
differentiated lymphocytes initiate microbial elimination |
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What happens in the decline phase of the adaptive immune response? |
after microbial elimination the signal for lymphocyte activation disappears. Most of the cells activated by antigen die by apoptosis |
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What are B cells activated by? What does their activation result in? |
-by antigens -results in their proliferation (clonal expansion) and differentiation into effector cells that actively secret antibodies |
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What are antibodies? Where do they come from? What do they do? |
-a secreted BCR -released by B cells upon infection -neutralizes microbes and microbial toxins -stops microbes from gaining access to or colonizing host cells |
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What do T cells respond to? |
Respond to antigens BUT require antigen presentation |
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What does a T cell require to assist antigen recognition? |
co-receptors |
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What are the 2 classes of T cells? |
1. CD4+ helper T cells 2. CD8+ cytolytic T cells |
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What do CD4+ T cells do? |
-detect antigens presented by professional APCs -secrete cytokines to activate other components of the immune response (macrophages, B cells, etc.) |
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What do CD8+ T cells do? |
-detect microbial antigens presented by all nucleated cells -destroy the presenting cell |
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What do the Peripheral Lymphoid Organs do? |
concentrate antigens and lymphocytes to optimize interactions (why immune response is so quick) |
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What is the Lymphatic System? What does it do? How is it different than the circulatory system? |
-a network that transports fluids from tissues to the circulatory system -excess interstitial fluid is collected by the lymphatic system and is processed by lymph nodes prior to being returned to the circulatory system -unlike the circulatory system, it is not closed and has no central pump |
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What happens in the lymphatic system (4 things)? |
1) APCs drain from the periphery into lymph nodes 2) T cells enter lymph nodes 3) APCs activate T cells 4) Lymphocytes exit lymph nodes and enter circulation where they mediate microbial destruction |
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What are some differences between the innate and adaptive immune responses? |
-unlike innate, adaptive is not restricted to specific classes of microbial molecules -adaptive immune receptors are not encoded in the germline -adaptive immune responses improve or "adapt" upon repeated exposure to a given foreign or toxin microbe |
