The Immune System
a complex body defense system that protects the body against bacteria, viruses, fungi, toxins, and parasites
Immune System�Two Subdivisions
Innate immune system
~Present at birth
~Not antigen specific
~Present at all times
~Does not improve with
repeated exposure to
infectious agent
Adaptive Immune System
~Develops throughout life
~Antigen specific
~Lag time between
infection and response
~Me
Immune Response�Prime Purpose
to defend the life of the individual by identifying foreign substances in the body and developing a defense against them.
Host Response
The way an individual's body responds to the infection
The body responds by
~Sending certain cells to the infection site
~Producing biochemical substances to counteract the foreign invaders
Consequences of Loss of Immune Function
deadly to the body.
For example, AIDS
HIV disables a specific group of immune cells.
HIV+ individuals often develop infections from microorganisms that rarely cause infections in persons with healthy immune systems.
Overzealous Immune System
The immune system can become so intense in its response that it begins to harm the body that it is trying to protect.
An overzealous response of the immune system occurs in periodontitis.
Example�Overzealous Immune System
A streptococcal infection of the skin or pharynx stimulates the immune system.
Unfortunately, there are similarities between certain molecules in streptococcal bacteria and molecules in the human heart.
The immune responses against the streptococcal bacte
Components of the immune system that play an important role in combating periodontal disease
Cellular defenders (phagocytes, lymphocytes)
The complement system
Leukocytes
Act like independent single-cell organisms
Can move through tissues and capture microorganisms on their own
Two types that are important in periodontal disease are
~Polymorphonuclear leukocytes (PMNs)
~Monocytes/macrophages
Phagocytosis
the process by which leukocytes engulf and digest microorganisms
Polymorphonuclear Leukocytes (PMNs)
Also called neutrophils
Rapid responders, provide the 1st line of defense
Capture and destroy bacterial invaders
Short-lived cells; die when they become engorged with bacteria
Attracted to bacteria by a process called chemotaxis.
PMN contains many strong
Monocytes/Macrophages
Called monocytes when in the bloodstream
Called macrophages when in the tissues
Slower to arrive at the infection site than the PMNs
Surround and destroy bacteria
Long-lived cells seen in chronic inflammation
Lymphocytes
Small leukocytes that help defend the body
Two main types are
B lymphocytes (B cells)
T lymphocytes (T cells)
B Lymphocytes (B Cells)
Once activated, makes millions of antibodies and pours them into the bloodstream
Can differentiate into 2 types of B cells
Plasma B cells
Memory B cells
Antibodies
Y-shaped proteins
One end of the Y binds to the outside of the B cell
The other end of the Y binds to a microorganism and helps to kill it
Antibodies are known collectively as _________________.
immunoglobulins
Five major classes of immunoglobulins are
- Immunoglobulin M (IgM)
- Immunoglobulin D (IgD)
- Immunoglobulin G (IgG)
- Immunoglobulin A (IgA)
- Immunoglobulin E (IgE)
T Lymphocytes (T Cells)
The main function is to intensify the response of other immune cells (macrophages, B lymphocytes) to the bacterial invasion.
T cells produce substances called cytokines that further stimulate the immune response.
Cytokine�a general name for any protein th
Complement system
a complex series of proteins circulating in the blood that works to
- Facilitate phagocytosis of bacteria
- Kill bacteria directly by forming pores in bacterial cell membranes
Functions of Complement System
Destruction of pathogens
Opsonization of pathogens
Recruitment of phagocytes
Immune clearance
Destruction of Pathogens
Components of complement can destroy certain microorganisms directly by forming pores in their cell membranes.
For this task, the complement system creates a protein called the membrane attack complex.
This protein can puncture cell membranes of certain b
Opsonization of Pathogens
The complement system facilitates the capture and destruction of bacteria by phagocytes.
This process is called opsonization of pathogens.
Complement components coat the surface of bacteria, allowing the phagocytes to recognize, engulf, and destroy bacter
Recruitment of Phagocytes
The complement system can recruit additional phagocytic cells to the site of an infection.
Immune Clearance
The complement system acts as a "housekeeper" for the body by removing immune complexes from circulation.
Immune cells that are important in the control of periodontal disease are
~PMNs and macrophages�capture and destroy bacteria
-B lymphocytes�make antibodies
-T lymphocytes�intensify the response of other immune cells
Leukocyte Migration to the Tissues
To fight an infection, leukocytes travel through the bloodstream.
The thin layer of epithelial cells that line the interior surface of blood vessels is called the endothelium
Near the infection site, leukocytes push their way between the endothelial cells
Attraction of Leukocytes to the Infection Site
Chemotaxis is the process whereby leukocytes
~Enter the connective tissue
~Are attracted to the site of the infection in response to biochemical compounds released by the invading bacteria
steps in phagocytosis
Migration
leukocytes travel through the bloodstream to fight an infection.
Transendothelial migration
leukocytes push their way between the endothelial cells of the blood vessels and enter the connective tissue.
Inflammation
The body's reaction to injury or invasion by disease-producing organisms
The Body's Response to Inflammation
Focuses host defense components at the site of an infection to eliminate microorganisms and heal damaged tissue
Inflammatory Biochemical Mediators
Biologically active compounds secreted by cells that activate the body's inflammatory response
Mediators of importance in periodontitis include
Cytokines
Prostaglandins
Matrix metalloproteinases
Cytokines
Leukocytes secrete cytokines that play a major role in regulating the behavior of immune cells.
Chemokines�a subgroup of cytokines�cause additional immune cells to be attracted to the site of an infection or injury.
Acute Inflammation
A short-term, normal process that protects and heals the body.
The acute inflammation process is achieved by the increased movement of plasma and leukocytes from the blood into the injured tissues.
*Five Classic Signs of Acute Inflammation
Heat�a localized rise in temperature due to an increased amount of blood at the site
Redness�the result of increased blood in the area
Swelling�the result of accumulation of plasma and leukocytes at the site
Pain�excess fluid in the tissues puts pressure
**The Acute Inflammatory Response
Blood vessels near the infected site become more permeable.
PMNs are the first cells to arrive at the site.
PMNs release cytokines.
The liver produces C-reactive protein (CRP).
If the body succeeds in eliminating all the microorganisms, the tissue will he
If the acute inflammatory responses are not effective in controlling the invading microorganisms, the inflammatory response becomes ____________.
chronic
Chronic Inflammation
is a long-lived, out-of-control inflammatory response that continues for more than a few weeks.
It is a pathological condition that can destroy healthy tissue and cause more damage than the original problem.
The classic warning signs seen in acute inflamm
Why does Chronic Inflammation occur?
Chronic inflammation occurs because the body is unable to rid itself of invading organism.
The invading microorganisms are persistent and stimulate an exaggerated immune response.
When inflammation becomes chronic, the inflammatory response can become so
The Chronic Inflammatory Process
Chronic inflammation is characterized by an accumulation of macrophages.
Macrophages engulf and digest microorganisms.
Leukocytes release inflammatory mediators that perpetuate the inflammatory response.
Tissue damage is the hallmark of chronic inflammati
Examples of Chronic Inflammation
Associated with a number of disease conditions:
Rheumatoid arthritis
Diabetes
Asthma
Gingivitis
Periodontitis
Periods of Remission and Exacerbation
Signs and symptoms of chronic inflammation may partially or completely disappear during a period of remission.
The signs and symptoms may recur in all of their severity in a active period of disease known as exacerbation.
Inflammatory Chemical Mediators
are biologically active compounds secreted by cells that activate the body's inflammatory response.
Important mediators include:
IL-1, IL-6, and IL-8
Leukotrienes
Prostaglandins
TNF-alpha
The Immune System
a complex body defense system that protects the body against bacteria, viruses, fungi, toxins, and parasites
Immune System�Two Subdivisions
Innate immune system
~Present at birth
~Not antigen specific
~Present at all times
~Does not improve with
repeated exposure to
infectious agent
Adaptive Immune System
~Develops throughout life
~Antigen specific
~Lag time between
infection and response
~Me
Immune Response�Prime Purpose
to defend the life of the individual by identifying foreign substances in the body and developing a defense against them.
Host Response
The way an individual's body responds to the infection
The body responds by
~Sending certain cells to the infection site
~Producing biochemical substances to counteract the foreign invaders
Consequences of Loss of Immune Function
deadly to the body.
For example, AIDS
HIV disables a specific group of immune cells.
HIV+ individuals often develop infections from microorganisms that rarely cause infections in persons with healthy immune systems.
Overzealous Immune System
The immune system can become so intense in its response that it begins to harm the body that it is trying to protect.
An overzealous response of the immune system occurs in periodontitis.
Example�Overzealous Immune System
A streptococcal infection of the skin or pharynx stimulates the immune system.
Unfortunately, there are similarities between certain molecules in streptococcal bacteria and molecules in the human heart.
The immune responses against the streptococcal bacte
Components of the immune system that play an important role in combating periodontal disease
Cellular defenders (phagocytes, lymphocytes)
The complement system
Leukocytes
Act like independent single-cell organisms
Can move through tissues and capture microorganisms on their own
Two types that are important in periodontal disease are
~Polymorphonuclear leukocytes (PMNs)
~Monocytes/macrophages
Phagocytosis
the process by which leukocytes engulf and digest microorganisms
Polymorphonuclear Leukocytes (PMNs)
Also called neutrophils
Rapid responders, provide the 1st line of defense
Capture and destroy bacterial invaders
Short-lived cells; die when they become engorged with bacteria
Attracted to bacteria by a process called chemotaxis.
PMN contains many strong
Monocytes/Macrophages
Called monocytes when in the bloodstream
Called macrophages when in the tissues
Slower to arrive at the infection site than the PMNs
Surround and destroy bacteria
Long-lived cells seen in chronic inflammation
Lymphocytes
Small leukocytes that help defend the body
Two main types are
B lymphocytes (B cells)
T lymphocytes (T cells)
B Lymphocytes (B Cells)
Once activated, makes millions of antibodies and pours them into the bloodstream
Can differentiate into 2 types of B cells
Plasma B cells
Memory B cells
Antibodies
Y-shaped proteins
One end of the Y binds to the outside of the B cell
The other end of the Y binds to a microorganism and helps to kill it
Antibodies are known collectively as _________________.
immunoglobulins
Five major classes of immunoglobulins are
- Immunoglobulin M (IgM)
- Immunoglobulin D (IgD)
- Immunoglobulin G (IgG)
- Immunoglobulin A (IgA)
- Immunoglobulin E (IgE)
T Lymphocytes (T Cells)
The main function is to intensify the response of other immune cells (macrophages, B lymphocytes) to the bacterial invasion.
T cells produce substances called cytokines that further stimulate the immune response.
Cytokine�a general name for any protein th
Complement system
a complex series of proteins circulating in the blood that works to
- Facilitate phagocytosis of bacteria
- Kill bacteria directly by forming pores in bacterial cell membranes
Functions of Complement System
Destruction of pathogens
Opsonization of pathogens
Recruitment of phagocytes
Immune clearance
Destruction of Pathogens
Components of complement can destroy certain microorganisms directly by forming pores in their cell membranes.
For this task, the complement system creates a protein called the membrane attack complex.
This protein can puncture cell membranes of certain b
Opsonization of Pathogens
The complement system facilitates the capture and destruction of bacteria by phagocytes.
This process is called opsonization of pathogens.
Complement components coat the surface of bacteria, allowing the phagocytes to recognize, engulf, and destroy bacter
Recruitment of Phagocytes
The complement system can recruit additional phagocytic cells to the site of an infection.
Immune Clearance
The complement system acts as a "housekeeper" for the body by removing immune complexes from circulation.
Immune cells that are important in the control of periodontal disease are
~PMNs and macrophages�capture and destroy bacteria
-B lymphocytes�make antibodies
-T lymphocytes�intensify the response of other immune cells
Leukocyte Migration to the Tissues
To fight an infection, leukocytes travel through the bloodstream.
The thin layer of epithelial cells that line the interior surface of blood vessels is called the endothelium
Near the infection site, leukocytes push their way between the endothelial cells
Attraction of Leukocytes to the Infection Site
Chemotaxis is the process whereby leukocytes
~Enter the connective tissue
~Are attracted to the site of the infection in response to biochemical compounds released by the invading bacteria
steps in phagocytosis
Migration
leukocytes travel through the bloodstream to fight an infection.
Transendothelial migration
leukocytes push their way between the endothelial cells of the blood vessels and enter the connective tissue.
Inflammation
The body's reaction to injury or invasion by disease-producing organisms
The Body's Response to Inflammation
Focuses host defense components at the site of an infection to eliminate microorganisms and heal damaged tissue
Inflammatory Biochemical Mediators
Biologically active compounds secreted by cells that activate the body's inflammatory response
Mediators of importance in periodontitis include
Cytokines
Prostaglandins
Matrix metalloproteinases
Cytokines
Leukocytes secrete cytokines that play a major role in regulating the behavior of immune cells.
Chemokines�a subgroup of cytokines�cause additional immune cells to be attracted to the site of an infection or injury.
Acute Inflammation
A short-term, normal process that protects and heals the body.
The acute inflammation process is achieved by the increased movement of plasma and leukocytes from the blood into the injured tissues.
*Five Classic Signs of Acute Inflammation
Heat�a localized rise in temperature due to an increased amount of blood at the site
Redness�the result of increased blood in the area
Swelling�the result of accumulation of plasma and leukocytes at the site
Pain�excess fluid in the tissues puts pressure
**The Acute Inflammatory Response
Blood vessels near the infected site become more permeable.
PMNs are the first cells to arrive at the site.
PMNs release cytokines.
The liver produces C-reactive protein (CRP).
If the body succeeds in eliminating all the microorganisms, the tissue will he
If the acute inflammatory responses are not effective in controlling the invading microorganisms, the inflammatory response becomes ____________.
chronic
Chronic Inflammation
is a long-lived, out-of-control inflammatory response that continues for more than a few weeks.
It is a pathological condition that can destroy healthy tissue and cause more damage than the original problem.
The classic warning signs seen in acute inflamm
Why does Chronic Inflammation occur?
Chronic inflammation occurs because the body is unable to rid itself of invading organism.
The invading microorganisms are persistent and stimulate an exaggerated immune response.
When inflammation becomes chronic, the inflammatory response can become so
The Chronic Inflammatory Process
Chronic inflammation is characterized by an accumulation of macrophages.
Macrophages engulf and digest microorganisms.
Leukocytes release inflammatory mediators that perpetuate the inflammatory response.
Tissue damage is the hallmark of chronic inflammati
Examples of Chronic Inflammation
Associated with a number of disease conditions:
Rheumatoid arthritis
Diabetes
Asthma
Gingivitis
Periodontitis
Periods of Remission and Exacerbation
Signs and symptoms of chronic inflammation may partially or completely disappear during a period of remission.
The signs and symptoms may recur in all of their severity in a active period of disease known as exacerbation.
Inflammatory Chemical Mediators
are biologically active compounds secreted by cells that activate the body's inflammatory response.
Important mediators include:
IL-1, IL-6, and IL-8
Leukotrienes
Prostaglandins
TNF-alpha