Acquired Immunity: Humoral Response • Distinction of Humoral versus Cell-Mediated Acquired Immunity • Antigens and Antigenic Determinants: Non- self and MHC proteins • Cell Types of the Humoral Response and How they Develop • B and T cell receptors and immunglobulins (antibodies) • Antibody Structure and Classes • Activation of B cells and Clonal Selection • Immunity and Secondary Response Time • Antibody Actions
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Acquired Immunity: Humoral Response Distinction of Humoral versus Cell-Mediated Acquired Immunity Antigens and Antigenic Determinants: Non-self and MHC.
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Acquired Immunity: Humoral Response
• Distinction of Humoral versus Cell-Mediated Acquired Immunity
• Antigens and Antigenic Determinants: Non-self and MHC proteins
• Cell Types of the Humoral Response and How they Develop
• B and T cell receptors and immunglobulins (antibodies)
• Antibody Structure and Classes
• Activation of B cells and Clonal Selection
• Immunity and Secondary Response Time
• Antibody Actions
• Passive and Active Immunity
• Monoclonal Antibodies
• Cell-Mediated Immune System: T cells, Grafting
Body Defenses: Innate and AcquiredDefense Systems of the Body
Non-specific defense system (Innate Immune System)
• Mechanisms protect against a variety of invaders
• Responds immediately to protect body from foreign materials
(Innate immunity)
Specific defense system (Acquired Immune System: Humoral and Cell-Mediated)
• Specific defense is required for each type of invader
• Also known generically as just “the immune system”
Nonspecific (Innate) Body DefensesMechanical, Chemical, and Competitive Barriers
Saliva and tears destroy bacteria because they contain lysozyme.
Skin produces acidic sebum to limit bacterial growth and sebum fatty acids are fungistatic
, urine, blood, saliva
Nitric oxide (NO) released by macrophages inhibit ATP production
Iron-binding proteins in blood block microbial reproduction
Inflammation
Figure 16.9c, d
Serum proteins activated in a cascade.
Results:
• Opsonization
• Chemotaxis
• Transmembrane channel formation in cells tagged by antibodies (causing cytolysis)
• Triggers inflammation
The Complement System
Figure 16.10
Body Defenses: Innate and AcquiredDefense Systems of the Body
Non-specific defense system (Innate Immune System)
• Mechanisms protect against a variety of invaders
• Responds immediately to protect body from foreign materials
(Innate immunity)
Specific defense system (Acquired Immune System: Humoral and Cell-Mediated)
• Specific defense is required for each type of invader
• Also known generically as just “the immune system”
Acquired Immune System – Third Line of Defense
Antigen specific – recognizes and acts against particular foreign substances
Systemic – not restricted to the initial infection site
Has memory – recognizes and mounts a stronger attack on previously encountered pathogens
The Acquired Immune System is:
Types of Acquired Immunity
1. Humoral Immunity
• Antibody-mediated immunity in blood and lymph
• Cells produce chemicals for defense
2. Cellular immunity of the Cell-Mediated Immune System
• Cell-mediated immunity
• Cells target virally infected cells
Antigens (Nonself) Antigen: Any substance capable of
exciting the immune system and provoking an immune response
Examples of common antigens
• Foreign proteins
• Nucleic acids
• Large carbohydrates
• Some lipids
• Pollen grains
• Microorganisms
Antigenic determinants: substances (like glycoproteins) on the surface of antigens to which the immune system actually responds Receptor in the
immune system that "fits" the
antigenic determinant
Antigen
Antigens
Self-Antigens Human cells have many
surface proteins called major histocompatability complexes (MHC).
All body cells have MHC Class I proteins.
Our immune cells do not attack our own proteins
Our cells in another person’s body can trigger an immune response because they are foreign
• Restricts donors for transplants
Allergies Many small molecules (called
haptens or incomplete antigens) are not antigenic, but link up with our own proteins
The immune system may recognize and respond to a carrier-hapten combination
This immune response can be harmful rather than protective because it can attack small molecules mounted on our own cells or small molecules normally found in the environment that bind to carriers allergy or autoimmunity
Humoral (Innate) Immune Response
• Distinction of Humoral/Innate versus Cell-Mediate Response
• Antigens and Antigenic Determinants: Non-self and MHC proteins
• Cell Types of the Humoral Response and How they Develop
• B and T cell receptors and immunglobulines (antibodies)
• Antibody Structure and Classes
• Activation of B cells and Clonal Selection
• Immunity and Secondary Response Time
• Antibody Actions
• Passive and Active Immunity
• Monoclonal Antibodies
Cells of the Immune System Lymphocytes
• Originate from hemocytoblasts in the red bone marrow
• B lymphocytes become immunocompetent in the bone marrow
• T lymphocytes become immunocompetent in the thymus
Macrophages (certain mature granulocytes)
• Arise from monocytes
• Become widely distributed in lymphoid organs
Development of Lymphocytes
T cell maturation and "education"
B Cell Receptors, T Cell Receptors, and Immunoglobulins
B cell
Secreted (Exported) Immunoglobulin or
Antibody (Same V and C Regions as in B cell
receptors)
Variable (binding
) regions
Receptors on T Cells
Constant
regions
Receptors on B cells
T cell
Humoral (Innate) Immune Response
• Distinction of Humoral/Innate versus Cell-Mediate Response
• Antigens and Antigenic Determinants: Non-self and MHC proteins
• Cell Types of the Humoral Response and How they Develop
• B and T cell receptors and immunglobulines (antibodies)
• Antibody Structure and Classes
• Activation of B cells and Clonal Selection
• Immunity and Secondary Response Time
• Antibody Actions
• Passive and Active Immunity
• Monoclonal Antibodies
Immunoglobulins and Receptors Bind To Antigens
Agglutination of antigens
Different Classes of Antibodies
Humoral (Innate) Immune Response
• Distinction of Humoral/Innate versus Cell-Mediate Response
• Antigens and Antigenic Determinants: Non-self and MHC proteins
• Cell Types of the Humoral Response and How they Develop
• B and T cell receptors and immunglobulines (antibodies)
• Antibody Structure and Classes
• Activation of B cells and Clonal Selection
• Immunity and Secondary Response Time
• Antibody Actions
• Passive and Active Immunity
• Monoclonal Antibodies
B Cell Activation and Clonal Selection
Humoral
immunity movie
Secondary Response (Immunity)
Figure 12.13
Results of Antibody Binding to Antigen• Agglutination (coralling of the invader)
• Precipitation (removal of soluble antigens from blood and lymph)
• Neutralization (blocking antigen's activity and binding)