Transcript Ch 12 Adaptive Defense Overview

Pages 410-414
 third
line of defense
 Three important aspects:
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1. It is antigen specific
2. It is systemic
3. It has memory
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 Two
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Humoral immunity  antibody-mediated immunity
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types of immunity:
Provided by antibodies present in body fluids
Cellular immunity  cell-mediated immunity
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Targets virus-infected cells, cancer cells, and cells of foreign
grafts
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 Antigens
(nonself)
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Any substance capable of mobilizing the immune
system and provoking an immune response
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common antigens:
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Foreign proteins (strongest)
Nucleic acids
Large carbohydrates
Some lipids
Pollen grains
Microorganisms
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 Human
cells have many surface proteins that
our immune cells recognize
 This


concept restricts transplant potential
Another human’s cells can trigger an immune
response because they are foreign
Blood type is a great example as agglutination
takes place with a mismatch
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Agglutination Reaction
19-6
Lymphocytes—respond to specific antigens:
1.
B
lymphocytes (B cells)
 T lymphocytes (T cells)
2.
Antigen-presenting cells (APCs)
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Dendritic cells
Macrophages
B lymphocytes
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 Arise
from hemocytoblasts of bone marrow
 Become
immunocompetent before they
encounter the antigens they may attack
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T
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B
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cells
develop immunocompetence in the thymus
oversee cell-mediated immunity
cells
develop immunocompetence in bone marrow
provide humoral immunity
 Both
groups move to lymph nodes to await antigen
encounters
Haspi.org
 Engulf
antigens
 Present fragments of antigen on their own surfaces
T cells recognize these fragments
 T cells become activated
 T cells release chemicals called Cytokines which:
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enhance T cell activation
Stimulate activity of other T cells
Help to activate B cells and cytotoxic T cells
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 Arise
from monocytes in bone marrow
 phagocytize pathogens
 present parts of the antigens on their
surfaces, for recognition by T cells
 remain fixed in the lymphoid organs
 Secrete cytokines
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