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Chapter 22 Nonspecific Body Defenses and ImmunityAdvanced Biology Chapter 22 Nonspecific Body Defenses and Immunity
Nonspecific – Innate Specific – Adaptive
Intact skin and mucosa
Phagocytes Other cells (inflammatory)
Specific Defense B Cells and T Cells
Functional System No Organs Trillions of Cells
Resistance to Disease
Keratin provides a barrier – resistant to weak acids/bases and bacterial toxins
Acidic – pH 3-5, inhibits bacterial growth; sebum contains chemicals toxic to bacteria
Stomach – concentrated HCl and protein digesting enzymes
Saliva and lacrimal fluid contains lysozyme which destroys bacteria
Sticky mucus traps microorganisms
MACROPHAGES Derived from monocytes Free MAC wander all over
Kupffer cells -liver Alveolar cells – Lungs Permanent residents
WBC that can phagocytize
Neutrophils release defensins – kills everything around it, including itself
WBC Defend against parasitic worms by surrounding it and discharging enzymes
Some bacteria can replicate inside MACs, MACs are stimulated to release other chemicals (Nitric oxide)
Police the body Checks markers – releases cytolytic chemicals
Prevent Spread of damaging agents
Dispose of cell debris
Set stage for repair
Enhance the body’s nonspecific defenses by attacking microorganisms or hinder their ability to reproduce
Classical – Binding of antibodiesAlternative – Certain protein factors are initiated
Convergence on C3, Splitting it, C3a, C3bConvergence on C3, Splitting it, C3a, C3b. Initiates events that cause lysis, promotes phagocytosis and enhances inflammation
Message to tell other cells there is a virusThose cells synthesize “PKR” which interferes with viral replication
Pyrogens Pyro – fire
Causes liver/spleen to retain zinc/iron
Helps speed up metabolic rate of cells
Can denature bacterial enzymes
Chapter 22 Specific Body Defenses: ImmunityAdvanced Biology Chapter 22 Specific Body Defenses: Immunity
To mount an immune response is expensive. Lots of energy is requiredTo mount an immune response is expensive. Lots of energy is required. Being specific, energy is only expended when necessary.
Study of Immunity
Antigen-Specific Systemic Memory
Humoral (Antibody-mediated)Cellular (Cell-mediated)
Intruders Not self
Immunogenicity – stimulate the proliferation of specific lymphocytes and antibody production
Reactivity – Ability to react with lymphocytes or antibodies
Part of antigen that is immunogenicBinds to it
Self-antigen Major Histocompatibility Complex (MHC)
Class I MHC – All body cellsClass II MHC – Immune Response Cells
Antigen Presenting Cells (APC)
B Lymphocytes (Humoral)
T Lymphocytes (Cell mediated)
To be able to recognize a specific antigen
Before meeting antigenIt is in your genes An antigen only determines which B or T cell will proliferate and attack
Engulfs antigen, shows it to a T cell
Chapter 22 Humoral Immune ResponseAdvanced Biology Chapter 22 Humoral Immune Response
Not a game show
1st Encounter b/w immunocompetent lymphocyte and invading antigen
3 to 6 Days Takes time for B cells to differentiate
2ndry much faster, more prolonged and more effective. 2-3 day responseSee pg 775
The capacity to produce a powerful 2ndry humoral response
When B cells encounter antigens and produce antibodies against them
Naturally acquired: During bacterial & viral infections
Artificially acquired: Through vaccine
Dead or attenuated (living but weakened) pathogens
Spare us from most of the symptomsProvide functional antigenic determinates
No memory is establishedFetus to mother
IgD – Attaches to B cells, activates B cells
IgM – Large, pentamer shapeIgM – Large, pentamer shape. Antigen receptive, 1st Ig released during primary response. Fixes and activates complement
IgG – Most abundant – 75-85%. Crosses placenta, protects against bacteria, viruses and toxins. Fixes complement.
IgA – Dimer (2), found in body secretions, helps prevent attachment of pathogens to epithelial cells
IgE – Stem region is bound to mast cells and basophils (allergies)
Neutralization – blocks specific sites on viruses and bacteria
Agglutination – Clumping of cells
Precipitation – not rain.Antigen molecules, not cells, are clumped together. See page 780.
Chapter 22 Cell-Mediated Immune ResponseAdvanced Biology Chapter 22 Cell-Mediated Immune Response
Microorganisms that slip inside body cellsTrying to avoid immune system
CD4 = T4, Helper Ts CD8 = T8, Cytotoxic Ts
Through processed parts on an APC
Provide means for signaling to immune system cells that infectious microorganisms are hiding in body cells
Step 1: Antigen Binding T cell antigen receptors, TCRs, bind to an antigen-MHC protein complex
Helper Ts bind to MHC II – w/help of APCCytotoxic Ts bind to MHC I – needs no APC
Step 2: Costimulation If bound to right costimulator (protein, chemicals), stimulation (proliferation) occurs. W/O right match, T cell activity is stopped
Mediators involved in cellular immunity
Lymphokines – released by activated T cellsMonokines – secreted by MACs
Interleukin 1 & 2 – IL 1 released by MACs tells T cells to liberate IL 2, which encourages T cells to divide more rapidly.
Tumor Necrosis Factor (TNF) – enhances nonspecific cell killing
Perforin/lymphotoxin are cell toxins that T cells can releasePerforin/lymphotoxin are cell toxins that T cells can release. Lethal Hit.
Gamma Interferon – enhance killing power of MACs
Regulatory cells Interact with B cells
Major function is to chemically or directly stimulate proliferation of other T cells and B cells that have already become bound to antigen
W/O helper Ts, there is no immune response!!
Killer T cells They can directly attack and kill other cells
Main target is virus infected cells, also tissue cells that have been infected, parasites, cancer cells, foreign cells introduced by blood transfusions or organ transplants
Help stop immune response after antigen has been destroyed
Promote allergic reactions
Chapter 21 - The Immune System: Innate and Adaptive Body Defenses
NOTES: Specific Defenses / Immunity (UNIT 9 part 3)
The Immune Stystem.
Immunity Chapter 40 Section 2. Lymphatic System.
Ch. 43 The Immune System.
The Immune System. First lines of defense: Skin Mucus Stomach acid Digestive enzymes.
Non-specific defense mechanisms 1st line- skin and mucous –Cilia lined trachea, hairs in pathways 2nd line- –phagocytic WBC –antimicrobial proteins (compliment.
The Body’s Defenses Ch. 43.
The Immune System 1.The Innate System 2.The Adaptive System.
Acquired Immunity Defends Against Infection of Body Cells and Fluids By: Jonah Harrington, Josh Yi.
Immune System. System of chemicals, white blood cells, and tissues that protect the body against pathogens (disease causing microorganisms) Immune system.
IMMUNITY ABBOTTS 2010.
The Fight Against Infectious Diseases
Immunology NON-SPECIFIC RESPONSES – SPECIFIC RESPONSES –
The Immune system Role: protect body against pathogens
Immunity. Role: Defense Three major types of defense: - Physical and chemical barriers - Non-specific defense use various means - Specific defense:
Innate Defenses Surface barriers – Skin, mucous membranes, and their secretions ________________________________________ to most microorganisms _________________________________________.
Specific Immune Defense. Antigens Antibody-generator, Non-self, Large molecules Properties: ◦1. Immunogenicity ◦2. Reactivity Antigenic determinant or.
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