SECTION 22-6 B Cells and Antibody-mediated Immunity
B cell sensitization of activation
Sensitization – the binding of antigens to the B cell membrane antibodies
Antigens then displayed on B cell Class II MHC
TH cells activated by same antigen stimulate B cell
Active B cell differentiates into Memory B Cell or Plasma cell
Plasma cells synthesize and release antibody
Figure 22.20 The Sensitization and Activation of B Cells
Antibodies structure
Antibodies are Y-shaped proteins consisting of:
Two parallel polypeptide chains
Heavy chains and light chains
Constant region and variable region
Antigen binding site
Figure 22.21 Antibody Structure
Figure 22.21 Antibody Structure
Figure 22.21 Antibody Structure
Actions of antibodies include:
Neutralization
Agglutination and precipitation
Activation of complement
Attraction of phagocytes
Opsinization
Stimulation of inflammation
Prevention of adhesion
Classes of Antibodies (immunoglobins)
IgG – resistance against many viruses, bacteria and bacterial toxins
IgE – accelerates local inflammation
IgD – found on the surface of B cells
IgM – first type secreted after antigen arrives
IgA – primarily found in glandular sec
Primary and secondary antibody response
Primary response
Takes about two weeks to develop
The Lymphatic System and Immunity
Produced by plasma cells
Secondary response
Rapid increase in IgG
Maximum antibody titer app
Figure 22.22 The Primary and Secondary Immune Responses
Figure 22.23 An Integrated Summary of the Immune Response
Figure 22.25 The Course of the Body’s Response to Bacterial Infection
Focus on Hormones of the Immune System
Interleukins
Increase T cell sensitivity
Stimulate B cell activity, plasma formation, and antibody production
Enhance nonspecific defenses
Moderate the immune system
Interferons
Tumor Necrosis Factors (TNFs) slow tumor growth
Colony Stimulating Factors (CSFs)
SECTION 22-7 Normal and Abnormal Resistance
Development of the Immune Response
Immunological competence
The ability to demonstrate an immune response after exposure to an antigen
Fetuses receive immunity from the maternal bloodstream
Infants acquire immunity following exposure
Immune disorders
Autoimmune disorders
Immune response mistakenly targets normal cells
Immunodeficiency diseases
Immune system does not develop properly or is blocked
Allergies
Inappropriate or excessive immune response to allergens
Immediate hypersensitivity (type I)
Cytotoxic reactions (type II)
Immune complex disorders (type III)
Delayed hypersensitivity (type IV)
Anaphylaxis
Circulating allergen affects mast cells throughout body
Figure 22.26 The Mechanism of Anaphylaxis
Stress and the immune response
Interleukin-1 released by active macrophages
Triggers release of ACTH resulting in glucocorticoid release
Moderates the immune response
Lowers resistance to disease
Stress can cause the following:
Depression of the inflammatory response
Phagocytic reduction
Inhibition of interleukin secretion
SECTION 22-8 Aging and the Immune Response
With age
Immune system becomes less effective
Increased susceptibility to infection
Immune surveillance declines
You should now be familiar with:
The structure and function of lymphatic cells, tissues and organs
The body’s nonspecific defenses and the components and mechanisms of each
Specific resistance, cell-mediated immunity and antibody mediated immunity
The role of the T cell, B cell and antibodies in specific immunity
The origin, development, activation and regulation of normal resistance to disease
The effects of stress and aging on the immune system
