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Chapter 17
Disease and Resistance:
The Wars Within
Chapter Outline
Introduction
A. The Host-Parasite Relationship
1. Introduction
Case history of Staphylococcus aureus from tattoo
Infection vs. disease
Normal microflora of body
2. Concepts of infectious disease
Pathogenicity, pathogen
Parasite, parasitism
Opportunistic parasites
Virulence
Levels of virulence
Avirulence
Pathogenicity islands
Levels of infectious disease in a population
Endemic
Epidemic
Pandemic
Modes of transmission
Direct methods
Physical contact
Droplet exposure
Indirect methods
Consumption of contaminated food/water
Fomites
Arthopods
Mechanical vector
Biological vector
Reservoirs
Carrier
Animals
3. The establishment of disease
Portal of entry
Portal of exit
Dose
Explanations for differing doses
Virulence factors
Invasiveness
Microbial enzymes
Coagulase
Streptokinase
Toxins
Exotoxins
Clostridium botulinum example
Antitoxins
Toxoids
Endotoxins
Endotoxin shock
B. Nonspecific Resistance to Disease
1. Introduction
Overview of human body
Characteristics of nonspecific resistance
Species immunity
2. Mechanical and chemical barriers
Intact skin
Conditions of skin
Mucous membranes
Conditions of vaginal tract
Antimicrobial substances made by body
Stomach acid (low pH)
Lysozyme (enzyme)
Interferon (antiviral)
3. Phagocytosis and other factors
Metchnikoff and phagocytosis
Phagocytes
Macrophages
Development of phagosome
Inflammation
Characteristic signs – rubor, calor, tumor, dolor
Pus accumulation
Fever
C. Specific Resistance and the Immune System
1. Antigens
Description
Proteins & carbohydrates as antigens
Antigenic determinant (epitope)
Specific immunologic tolerance
2. Origin of the immune system
Lymphocytes
B cells, T cells
Development of immune system
Lymphopoietic cells
Thymus maturation (T cells)
Immunocompetent cells
Bursa of Fabricius maturation (B cells)
Surface receptor proteins
Origination of immune response
Specific responsibilities of T cells and B cells
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3. Cell-mediated immunity (CMI)
Overview of CMI
Steps of CMI
Display of antigenic determinants
Antigen-presenting cell
Matching of MHC proteins
Cytotoxic T cell, helper T cell (CD4)
Simulation of cytotoxic T cell
Search for antigenic determinants by cytotoxic T cell
Perforin release
Lymphokine release
Attraction of macrophage
Prevention of macrophage exit
Transfer factor
Formation of memory T cells
4. Antibody-mediated immunity (AMI)
Overview of AMI (humoral immunity)
Steps of AMI
B cell activation
Role of helper T cells and MHC proteins
Production of lymphokines
Activation of helper T cells
Development of plasma cells
Production of antibodies (immunoglobulin or Ig)
Development of memory B cells
Structure of antibodies
Heavy (H) & light (L) chains
Constant vs. variable regions
Somatic recombination
Types of antibodies
IgM (macroglobulin)
1st in circulation
IgG (gamma globulin)
Major circulatory one
Maternal antibody
IgA
Serum IgA
Secretory IgA – tears, saliva colostrum
IgD
Possible cell surface receptor on B cells
Antigen-antibody interactions
Neutralizing antibodies
Antitoxins
Agglutinins
Precipitins
Complement system
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Types of immunity
Innate immunity
Acquired immunity
Active immunity vs. passive immunity
Naturally acquired active immunity
Artificially acquired active immunity
Naturally acquired passive immunity
Artificially acquired passive immunity
5. Destructive immune processes
Hypersensitivity reactions
Anaphylaxis
Anaphylactic shock
Symptoms and development
Allergy
Hay fever
Food allergies
Cytotoxic hypersensitivity
Transfusion reaction
Hemolytic disease of the newborn (Rh disease)
Thrombocytopenia
Immune complex hypersensitivity
Systemic lumpus erythematosus (SLE)
Rheumatoid arthritis
Cellular hypersensitivity
Poison ivy as example
Symptoms and development
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