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Immunity: Part IV
Acquired Immunity
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Remember: Types of Immunity
• Innate
• Acquired
– Is the body’s second major kind of defense
– Involves the activity of lymphocytes
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
• A summary of innate and acquired immunity
INNATE IMMUNITY Rapid responses to a
broad range of microbes
ACQUIRED IMMUNITYSlower responses to
specific microbes
External defenses Internal defenses
Skin
Mucous membranes
Secretions
Phagocytic cells
Antimicrobial proteins
Inflammatory response
Natural killer cells
Humoral response(antibodies)
Cell-mediated response(cytotoxic lymphocytes)
Invadingmicrobes
(pathogens)
Notes Handout
Types of Immunity
Properties of Immunity
1.Specificity
2.Versatility
3.Memory
4.Tolerance
Notes Handout
Figure 14.16
Notes Handout
Figure 14.12
T Cells & Cell-Mediated Immunity
• T Cells must be activated by exposure to antigen
• T Cells recognize antigens when they are bound to membrane receptors of other cells
• Antigen membrane receptors are called– MAJOR HISTOCOMPATIBILITY COMPLEX
PROTEINS • Class I MHC • Class II MHC
T Cells & Cell-Mediated Immunity
• MHC Proteins• Class I
– Found on the surface of all nucleated cells– Peptides produced inside the cell are displayed on
the surface by Class I MHC proteins.
• Class II– Found on the surface of lymphocytes & phagocytes
• Called ANTIGEN-PRESENTING CELLS (APCs)
Types of T Cells
1. Cytotoxic T Cells
2. Helper T Cells
3. Memory T Cells
4. Suppressor T Cells
Notes Handout
Helper T Cells• Activated by exposure to antigens presented by
Class II MHC proteins• Activated helper T cells perform two functions:
1. Coordinate specific & nonspecific defenses
2. Stimulate both cell-mediated & antibody-mediated immunity
• Activated helper T cells divide to produce:– More activated helper T cells– Memory T cells
• helper T cells clip
Memory T Cells
• Produced upon initial exposure to antigen, but do not respond to the antigen at that time.
• Provide a no-delay response to any FUTURE exposure to the same antigen– Immediate differentiation into cytotoxic T cells
and helper T cells
Suppressor T Cells
• Activated suppressor T cells dampen the responses of other T cells and B cells– Secrete suppression factors
• Act after the initial immune response
Notes Handout
Sensitization & Activation of B Cells
Sensitization & Activation of B Cells
Sensitization & Activation of B Cells
Sensitization & Activation of B Cells
Notes Handout
Antibody Structure
Antigen-antibody binding
Antibody (IgG) Function
• Neutralization• Agglutination and precipitation• Activation of complement• Attraction of phagocytes• Enhancement of phagocytes• Stimulation of inflammation
Notes Handout
Summary of the Immune Response and Its Relationship to Nonspecific Defenses
Notes Handout
Integration of the Lymphatic System with Other Systems