B11-5-02 Immune Response
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Transcript B11-5-02 Immune Response
3rd Line – Immune
Response
B11-5-02 – Body’s response to viruses/bacteria
Immune System Video
The 3 Lines of Defense
The 1st line of
Defense
Barriers
The 2nd line of
Defense
Inflammatory response
The 3rd line of
Defense
Immune response
Immune system distinguishes “self” from
“non-self”
Do not react with our own cells
Generates specific response to specific
invaders
Builds up resistance against Pathogens
Antigen
Tailored to an individual threat
Most effective
Memory component
Improves response time
Immune Response
Two types of specific immune response
Antibody-mediated
Cell-mediated
Antibody-Mediated
Immunity
Antibody-Mediated Immunity
Production of antibodies specific to a given
antigen
Antibodies bind to the antigens on invaders
and kill or inactivate them
Antigens are molecules that cause antibody
production
Response provided by B cells
(lymphocytes derived from bone marrow)
Lymphocyste Video
In Response to Infection
A few days after an infection
Antigens cause the production of large
amount of the antibody capable of interacting
with it
Specific antibodies bind specific antigens
Antibodies
Antibodies bind antigens in a lock-and-key
fashion
Forming antigen-antibody complex
Type of protein
Immunoglobulin
Y shaped molecules with
Two heavy chains
Two light chains
Antibodies Cont.
Identify Antigens as either
Self
Nonself
Bind non-self antigens clumping them
together making them inactive
Antibodies Cont.
Body only has antibodies for pathogens
that a host has encountered
When a new pathogen invades the body,
B-cells “learn” about new antigens and
develop appropriate antibodies
The B-Cells then circulate though the
body, releasing antibodies that bind to new
antigen
Antibodies Video 1
Antibodies Video 2
Antigens
Protein or polysaccharide that is present
on the plasma membrane
Cell-Mediated Immunity
Cell-mediated Immunity
Require direct physical contact with
antigens
Does not involve the production of
antibodies
Response provided by T-Cells
(lymphocytes derived from the thymus)
Four types
1. Cytotoxic (Killer) T-Cells
Defend the body by destroying
Foreign cells
Infected cells
Cancerous cells
Recognizes viral antigens on plasma
membrane of host cell
Attaches to plasma membrane of host cell
Secrete enzymes that digest host plasma
membrane
Punching holes
Infected cell’s cytoplasm leaks out and the
cell dies
The dead cell and its contents are
removed by phagocytes
2. Helper T-Cells
Regulate immune response by …
Secreting messenger proteins
Direct contact with other cells
Helps Killer T-Cells and B-Cells to perform
their function
Are destroyed by the HIV virus in patients
with Acquired Immune Deficiency
Syndrome (AIDS)
3. Suppressor T Cells
Reduce the immune response of B cells
and T cells to keep them in check
4. Memory T Cells
Remain in the body awaiting the
reintroduction of the antigen
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13.3 INDUCED IMMUNITY
Active Immunity (250)
Passive Immunity (251)