Chapter 43 The Immune System. Protection From Invaders Your body has a variety of mechanisms to protect it from invasion. 1. The skin 2. Mucous

Chapter 43Chapter 43

The Immune SystemThe Immune System

Protection From Invaders

Protection From Invaders

Your body has a variety of mechanisms to protect it from invasion. 1. The skin 2. Mucous 3. Ciliated lining of the trachea

4. Internal cellular and chemical defenses via phagocytes

Your body has a variety of mechanisms to protect it from invasion. 1. The skin 2. Mucous 3. Ciliated lining of the trachea

4. Internal cellular and chemical defenses via phagocytes

2 Major Types of Defense

2 Major Types of Defense

1. Innate immunity 2. Acquired immunity

1. Innate immunity 2. Acquired immunity

1. Innate Immunity1. Innate Immunity

This type of immunity is present before any exposure to pathogens and is available at birth.

Innate responses help slow the spread of microbes before the body can build acquired, specific responses.

This type of immunity is present before any exposure to pathogens and is available at birth.

Innate responses help slow the spread of microbes before the body can build acquired, specific responses.

2. Acquired Immunity2. Acquired Immunity

This immunity develops after exposure to foreign substances.

Acquired defenses are highly specific.

They have the ability to distinguish between very closely related inducing agents.

Specificity is achieved by lymphocytes.

This immunity develops after exposure to foreign substances.

Acquired defenses are highly specific.

They have the ability to distinguish between very closely related inducing agents.

Specificity is achieved by lymphocytes.

1. The Skin1. The Skin

The skin secretes oils and sweat. It has a normal pH of 3 to 5 which prevents colonization of bacteria on the skin.

Secretions from the skin also contain lysozyme which digest the cell walls of many bacteria.

It is found in tears, mucous, saliva, etc.

The skin secretes oils and sweat. It has a normal pH of 3 to 5 which prevents colonization of bacteria on the skin.

Secretions from the skin also contain lysozyme which digest the cell walls of many bacteria.

It is found in tears, mucous, saliva, etc.

2. & 3. Mucous and Cilia

2. & 3. Mucous and Cilia

Mucous often traps invaders and cilia sweeps them out of the trachea. They are either swallowed where they usually fall victim to the low pH of the stomach.

They may also be expectorated.

Mucous often traps invaders and cilia sweeps them out of the trachea. They are either swallowed where they usually fall victim to the low pH of the stomach.

They may also be expectorated.

4. Internal Defenses-Phagocytes


Are certain types of WBC’s that produce antimicrobial proteins.

Help initiate inflammation. This helps limit the spread of microbes in the body.

Non phagocytic WBC’s are called natural killer cells.

These play a key role in innate defenses.

Are certain types of WBC’s that produce antimicrobial proteins.

Help initiate inflammation. This helps limit the spread of microbes in the body.

Non phagocytic WBC’s are called natural killer cells.

These play a key role in innate defenses.

The 4 Types of Phagocytic WBC’sThe 4 Types of

Phagocytic WBC’s 1. Neutrophils 2. Macrophages 3. Eosinophils 4. Dendritic cells

1. Neutrophils 2. Macrophages 3. Eosinophils 4. Dendritic cells

1. Neutrophils1. Neutrophils

1. Neutrophils--most WBC’s (60-70%). They are attracted to infected tissue.

They engulf and destroy microbes.

They only last a few days.

1. Neutrophils--most WBC’s (60-70%). They are attracted to infected tissue.

They engulf and destroy microbes.

They only last a few days. QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Source: www.chronicprostatitis.com/ images/neutrophil.jpg

QuickTime™ and aTIFF (Uncompressed) decompressor


Source: www.chmeds.ac.nz/ research/freerad/tony.htm



2. Macrophages2. Macrophages

2. Macrophages--big eaters, small portion of WBC’s (5%). They are long-lived. They help elicit the 2° immune response.

Permanent residents of the spleen and lymph nodes.

They eliminate microbes trapped here.

2. Macrophages--big eaters, small portion of WBC’s (5%). They are long-lived. They help elicit the 2° immune response.

Permanent residents of the spleen and lymph nodes.

They eliminate microbes trapped here.





Source: www.proneuron.com/Therapies/ MacrophageSCI.html

microbiology.otago.ac.nz/. ../Macrophage.jpg



www.bloodlines.stemcells.com/ chapters.html

3. Eosinophils3. Eosinophils

3. Eosinophils--less abundant and work by attracting themselves to the invader and releasing enzymes that destroy them (2%-4%).

3. Eosinophils--less abundant and work by attracting themselves to the invader and releasing enzymes that destroy them (2%-4%).



cellbio.utmb.edu/.../ blood/more_eosinophils.htm



faculty.une.edu/com/ abell/histo/histolab3a.htm

http://faculty.une.edu/com/abell/histo/histolab3a.htm






4. Dendritic Cells4. Dendritic Cells

4. Dendritic cells ingest microbes, and stimulate the development of acquired immunity.

The help elicit the 1° immune response.

4. Dendritic cells ingest microbes, and stimulate the development of acquired immunity.

The help elicit the 1° immune response.



In this picture a mature dendritic cell (the cell on the right with dendrites) is moving towards a T lymphocyte (little rounded cell). The contact between a mature dendritic cell and a T lymphocytes is the initial step of an immune response. www.innovations-report.com/bilder_neu/14759_image02.jpg



Phagocytes bind to the surfaces of invading cells.

They use surface receptors to recognize structures found on microorganisms, but not normal body cells.

After binding the invader, the phagocyte engulfs the invader, forms a vacuole, and fuses with a lysosome.

Phagocytes bind to the surfaces of invading cells.

They use surface receptors to recognize structures found on microorganisms, but not normal body cells.

After binding the invader, the phagocyte engulfs the invader, forms a vacuole, and fuses with a lysosome.

LysosomesLysosomes

There are 2 ways lysosomes work: 1. They poison the invader.

NO and other toxic forms of O2 are made in the lysosome.

2. Lysozyme and other enzymes degrade invader components.

Some microbes make substances that allow them to go unnoticed against the body’s defenses.

There are 2 ways lysosomes work: 1. They poison the invader.

NO and other toxic forms of O2 are made in the lysosome.

2. Lysozyme and other enzymes degrade invader components.

Some microbes make substances that allow them to go unnoticed against the body’s defenses.

Natural Killer CellsNatural Killer Cells

NK cells patrol the body and attack virus infected body cells and cancer cells.

They recognize surface proteins and act to release chemicals into the cell triggering apoptosis.

Not 100% effective.

NK cells patrol the body and attack virus infected body cells and cancer cells.

They recognize surface proteins and act to release chemicals into the cell triggering apoptosis.

Not 100% effective.



A human natural killer cell is shown conjugated to a tumor cell. The accumulation of actin filaments (blue) and CD2 (red) at the immunologic synapse can be seen preceding the localization of the cytolytic molecule perforin (green).

Tissue DamageTissue Damage

Physical injury or pathogens can cause tissue damage and localized swelling.

Numerous chemical signals are released.

The most active one is histamine which comes from mast cells.

Physical injury or pathogens can cause tissue damage and localized swelling.

Numerous chemical signals are released.

The most active one is histamine which comes from mast cells.



www.aapspharmscitech.org/ view.asp?art=pt060361

HistamineHistamine Triggers dilation and increased permeability of capillaries.

Activated macrophages and other cells discharge other signals, such as prostaglandins.

Prostaglandins promote more blood flow the the injury site.

Triggers dilation and increased permeability of capillaries.

Activated macrophages and other cells discharge other signals, such as prostaglandins.

Prostaglandins promote more blood flow the the injury site.

The Injury SiteThe Injury Site

The swelling and increased heat are critical to innate defense.

They deliver the necessary components to the site of injury (clotting factor and antimicrobial protein).

The swelling and increased heat are critical to innate defense.

They deliver the necessary components to the site of injury (clotting factor and antimicrobial protein).

AntigensAntigens

Foreign molecules that are recognized by lymphocytes and elicit a response from them.

Lymphocytes bind to the epitope on an antigen.

Foreign molecules that are recognized by lymphocytes and elicit a response from them.

Lymphocytes bind to the epitope on an antigen.

2. Acquired Immunity- Lymohocytes

2. Acquired Immunity- Lymohocytes

Lymphocytes produce 2 main types of immune responses:

1. Humoral response Circulating antibodies produced by B-lymphocytes

2. Cell mediated response Antibodies produced by T-lymphocytes

Lymphocytes produce 2 main types of immune responses:

1. Humoral response Circulating antibodies produced by B-lymphocytes

2. Cell mediated response Antibodies produced by T-lymphocytes

1. The Humoral Response


Occurs when cells derived from B-lymphocytes become activated and secrete defensive proteins called antibodies.

Secreted antibodies accumulate in the blood and lymph.

Occurs when cells derived from B-lymphocytes become activated and secrete defensive proteins called antibodies.

Secreted antibodies accumulate in the blood and lymph.



They identify and bind to microbes and mark them for elimination.

Clonal selection is also involved.

They identify and bind to microbes and mark them for elimination.

Clonal selection is also involved.

Clonal SelectionClonal Selection

The antibody-driven cloning of T & B lymphocytes is called clonal-selection and is fundamental to acquired immunity.

When antigens bind to specific receptors, a small fraction of the body’s lymphocytes are activated.

This stimulates the production of thousands of clones that work to eliminate an antigen.

The antibody-driven cloning of T & B lymphocytes is called clonal-selection and is fundamental to acquired immunity.

When antigens bind to specific receptors, a small fraction of the body’s lymphocytes are activated.

This stimulates the production of thousands of clones that work to eliminate an antigen.

Primary Immune Response

Primary Immune Response

The primary immune response is the first time exposure to an antigen.

Proliferation of lymphocytes occurs.

Individual may become sick. Eventually antibodies clear the antigen from the system.

The primary immune response is the first time exposure to an antigen.

Proliferation of lymphocytes occurs.

Individual may become sick. Eventually antibodies clear the antigen from the system.

Secondary Immune Response

Secondary Immune Response

The 2° immune response occurs if an individual is exposed to an antigen again.

It is an example of immunological memory.

It depends on long lived T and B memory cells.

They elicit a quick and specific response to the antigen.

The 2° immune response occurs if an individual is exposed to an antigen again.

It is an example of immunological memory.

It depends on long lived T and B memory cells.

They elicit a quick and specific response to the antigen.

LymphocytesLymphocytes

There are two main types of lymphocytes: 1. B-cells 2. T-cells

They are concentrated in the spleen, lymph nodes, and other lymphoid tissues.

There are two main types of lymphocytes: 1. B-cells 2. T-cells

They are concentrated in the spleen, lymph nodes, and other lymphoid tissues.


They act to recognize antigens by a means of antigen specific receptors embedded in their membrane.

Stimulate production of T & B cells.

A single T or B cell has about 100,000 antigen-receptors.

All of them are the same on a particular cell--they recognize the same epitope.

They act to recognize antigens by a means of antigen specific receptors embedded in their membrane.

Stimulate production of T & B cells.

A single T or B cell has about 100,000 antigen-receptors.

All of them are the same on a particular cell--they recognize the same epitope.


Derived from pluripotent stem cells in the bone marrow.

Each lymphocyte displays specificity for a particular epitope on an antigen

It defends against that antigen and other closely related antigens.

Derived from pluripotent stem cells in the bone marrow.

Each lymphocyte displays specificity for a particular epitope on an antigen

It defends against that antigen and other closely related antigens.

1. B-Cell Lymphocytes1. B-Cell Lymphocytes

Originate and mature in the bone marrow.

B-cell chains are anchored into a membrane of the B-cell.

They are sometimes called membrane antibodies or membrane immunoglobulins.

B-cells recognize intact antigens.

Originate and mature in the bone marrow.

B-cell chains are anchored into a membrane of the B-cell.

They are sometimes called membrane antibodies or membrane immunoglobulins.

B-cells recognize intact antigens.

1. B-Cell Lymphocytes1. B-Cell Lymphocytes

B-cells help with presenting antigens to helper T-cells in the course of the humoral response.

B-cells help with presenting antigens to helper T-cells in the course of the humoral response.

B-Cell ReceptorsB-Cell Receptors B-cell receptors for antigens are Y-shaped.

They contain 4 polypeptide chains 2 heavy chains and 2 light chains.

V regions are variable, their aa sequence varies extensively from one B-cell to the next.

C regions are constant and have little variability in their sequence.

B-cell receptors for antigens are Y-shaped.

They contain 4 polypeptide chains 2 heavy chains and 2 light chains.

V regions are variable, their aa sequence varies extensively from one B-cell to the next.

C regions are constant and have little variability in their sequence.

ImmunoglobulinsImmunoglobulins

These are called Ig’s Are structurally very similar to B-cell receptors.

They lack transmembrane regions.

They are made by B-lymphocytes (B-cells) in large quantities.

These are called Ig’s Are structurally very similar to B-cell receptors.

They lack transmembrane regions.

They are made by B-lymphocytes (B-cells) in large quantities.

ImmunoglobulinsImmunoglobulins

There are 5 main classes. IgG IgM IgA IgD IgE

There are 5 main classes. IgG IgM IgA IgD IgE

IgGIgG

It is the main Ig in blood, lymph and tissue fluid.

It neutralizes microorganisms, viruses, and bacterial toxins by binding to them.

Promotes engulfment by macrophages.

Activates compliment-part of innate system.

It is the main Ig in blood, lymph and tissue fluid.

It neutralizes microorganisms, viruses, and bacterial toxins by binding to them.

Promotes engulfment by macrophages.

Activates compliment-part of innate system.

IgMIgM

Found in blood and lymph. First antibody produced following infection or immunization.

Has numerous binding sites. Activates compliment-part of innate system.

Found in blood and lymph. First antibody produced following infection or immunization.

Has numerous binding sites. Activates compliment-part of innate system.

IgAIgA

Found in serum, saliva, tears, breast milk, and mucous secretions.

Neutralizes viruses and bacteria as they enter the body.

Found in serum, saliva, tears, breast milk, and mucous secretions.

Neutralizes viruses and bacteria as they enter the body.

IgDIgD

Found on the surface of antibody secreting B-cells.

Found in low concentrations. Works with IgM as an antigen receptor.

Found on the surface of antibody secreting B-cells.

Found in low concentrations. Works with IgM as an antigen receptor.

IgEIgE

Found in low concentrations in serum and connective tissues.

Plays a crucial role in allergic reactions.

Binds to mast cells causing a histamine release in response to an antigen.

The histamines produce all of the symptoms associated with allergies: Swelling, redness, runny nose and eyes.

Found in low concentrations in serum and connective tissues.

Plays a crucial role in allergic reactions.

Binds to mast cells causing a histamine release in response to an antigen.

The histamines produce all of the symptoms associated with allergies: Swelling, redness, runny nose and eyes.

The Complement SystemThe Complement System

The complement system comprises part of the innate defense.

Activated as a result of the humoral system (IgG, IgM).

Numerous inactive serum proteins.

Quickly become active and lyse foreign invaders when detected.

Example: and interferon.

The complement system comprises part of the innate defense.

Activated as a result of the humoral system (IgG, IgM).

Numerous inactive serum proteins.

Quickly become active and lyse foreign invaders when detected.

Example: and interferon.

InterferonInterferon

2 types ( and ) provide innate defense against viral infection.

They stimulate neighboring cells to produce substances to prevent further infection.

2 types ( and ) provide innate defense against viral infection.

They stimulate neighboring cells to produce substances to prevent further infection.

MHCMHC

Major histocompatibility complex genes code for MHC molecules.

When MHC molecules are synthesized, they get transported to the plasma membrane.

On the way, they bind with fragments of antigen protein within a cell and bring it to the surface.

Major histocompatibility complex genes code for MHC molecules.

When MHC molecules are synthesized, they get transported to the plasma membrane.

On the way, they bind with fragments of antigen protein within a cell and bring it to the surface.

MHCMHC

This is called antigen presentation.

A nearby T-cell can recognize this fragment on the cell surface.

MHC proteins are very polymorphic.

This is called antigen presentation.

A nearby T-cell can recognize this fragment on the cell surface.

MHC proteins are very polymorphic.

Foreign AntigensForeign Antigens

There are 2 ways foreign antigens end up inside cells of the body. Their source determines which MHC molecule gets used and which T-cell assist in its removal. 1. Foreign antigens synthesized within the cell.

2. Foreign materials can become internalized by phagocytosis or endocytosis

There are 2 ways foreign antigens end up inside cells of the body. Their source determines which MHC molecule gets used and which T-cell assist in its removal. 1. Foreign antigens synthesized within the cell.

2. Foreign materials can become internalized by phagocytosis or endocytosis

Class I MHC MoleculesClass I MHC Molecules

Found on most nucleated cells in body.

They bind antigens synthesized within the cell.

Infected cells and cancerous cells display such antigens.

Cytotoxic T-cells destroy cells displaying Class I MHC molecules.

Found on most nucleated cells in body.

They bind antigens synthesized within the cell.

Infected cells and cancerous cells display such antigens.

Cytotoxic T-cells destroy cells displaying Class I MHC molecules.

Class II MHC MoleculesClass II MHC Molecules

These are made by only a few types of cells-dendritic cells, macrophages, and B-cells.

These bind peptides derived from foreign materials that have been fragmented and internalized.

These are made by only a few types of cells-dendritic cells, macrophages, and B-cells.

These bind peptides derived from foreign materials that have been fragmented and internalized.

Class II MHC MoleculesClass II MHC Molecules

They display these antigens to helper T-cells.

Helper T cells alert nearby B-cells and cytotoxic T cells.

They display these antigens to helper T-cells.

Helper T cells alert nearby B-cells and cytotoxic T cells.

Immunoglobulin Gene Rearrangement

Immunoglobulin Gene Rearrangement

There are many different types of B-cell and T-cell antibodies.

This is due to the random nature of the recombinase enzyme.

It can create a number of different gene products which are the B-cell (or T-cell) antigen receptors.

There are many different types of B-cell and T-cell antibodies.

This is due to the random nature of the recombinase enzyme.

It can create a number of different gene products which are the B-cell (or T-cell) antigen receptors.

B-Cell & T-Cell Activation

B-Cell & T-Cell Activation

When B-cells and T-cells become activated by antigens, they stimulate them to divide many times.

2 clones of daughter cells are created. 1 is short lived, antibody secreting cell.

The other is a memory cell that is long lived and bears receptors for the same antigen.

When B-cells and T-cells become activated by antigens, they stimulate them to divide many times.

2 clones of daughter cells are created. 1 is short lived, antibody secreting cell.

The other is a memory cell that is long lived and bears receptors for the same antigen.

B-Cell ActivationB-Cell Activation

Many antigens recognized by B-cells contain multiple epitopes.

Exposure to a single antigen can stimulate a variety of different B-cells.

This gives rise to a clone of thousands of plasma cells (effector and memory).

These clones secrete antibodies specific to the epitope that provoked their production.

Many antigens recognized by B-cells contain multiple epitopes.

Exposure to a single antigen can stimulate a variety of different B-cells.

This gives rise to a clone of thousands of plasma cells (effector and memory).

These clones secrete antibodies specific to the epitope that provoked their production.

B-Cell ActivationB-Cell Activation

Secreted antibodies have a Y-shaped antigen-binding structure, but no transmembrane region.

These binding sites are responsible for identifying specific antigens.

Identification of antigens facilitates their removal.

Secreted antibodies have a Y-shaped antigen-binding structure, but no transmembrane region.

These binding sites are responsible for identifying specific antigens.

Identification of antigens facilitates their removal.

2. The Cell Mediated Response

2. The Cell Mediated Response

The cell mediated response and clonal selection occurs.

Cytotoxic lymphocytes directly destroy infected body cells, cancer cells, or foreign tissue.

There are 2 main types of T-cells 1. Helper T-cells 2. Cytotoxic T-cells

The cell mediated response and clonal selection occurs.

Cytotoxic lymphocytes directly destroy infected body cells, cancer cells, or foreign tissue.

There are 2 main types of T-cells 1. Helper T-cells 2. Cytotoxic T-cells

2. T-Cell Lymphocytes2. T-Cell Lymphocytes Originate in the bone marrow, mature in the thymus.

Consist of 2 polypeptide chains, & .

They, too, are linked into a cell’s plasma membrane.

They also have V and C regions. T-cells recognize fragments of antigens that are bound to normal cell-surface proteins called MHC molecules.

Originate in the bone marrow, mature in the thymus.

Consist of 2 polypeptide chains, & .

They, too, are linked into a cell’s plasma membrane.

They also have V and C regions. T-cells recognize fragments of antigens that are bound to normal cell-surface proteins called MHC molecules.

Helper T-CellsHelper T-Cells

These are central to the network of cellular interactions.

They respond to peptide antigens displayed on antigen presenting cells.

They stimulate activation of B-cells and cytotoxic T-cells.

These are central to the network of cellular interactions.

They respond to peptide antigens displayed on antigen presenting cells.

They stimulate activation of B-cells and cytotoxic T-cells.


When they encounter a class II MHC molecule-antigen complex, they stimulate the production of clones of helper T-cells and memory helper T-cells.

This promotes the removal of infected cells.

When they encounter a class II MHC molecule-antigen complex, they stimulate the production of clones of helper T-cells and memory helper T-cells.

This promotes the removal of infected cells.


They secrete many different cytokines (signals) to stimulate other lymphocytes.

This promotes humoral and cell mediated responses.

They secrete many different cytokines (signals) to stimulate other lymphocytes.

This promotes humoral and cell mediated responses.

Cytotoxic T-CellsCytotoxic T-Cells When activated, they secrete proteins which destroy the infected cell.

Circulating antibodies mark the exposed pathogens for disposal.

They are the effectors.

When activated, they secrete proteins which destroy the infected cell.

Circulating antibodies mark the exposed pathogens for disposal.

They are the effectors.

Disposal MechanismsDisposal Mechanisms

There are several ways to get rid of antigens:

1. Viral Neutralization 2. Agglutination 3. Precipitation 4. Opsonization

There are several ways to get rid of antigens:

1. Viral Neutralization 2. Agglutination 3. Precipitation 4. Opsonization

1. Viral Neutralization

1. Viral Neutralization

Occurs when antibodies to particular proteins bind to them on a virus’s surface.

Blocks binding on the host cell.

This prevents a virus from infecting a host cell.

Similar to opsonization.

Occurs when antibodies to particular proteins bind to them on a virus’s surface.

Blocks binding on the host cell.

This prevents a virus from infecting a host cell.

Similar to opsonization.

2. Agglutination2. Agglutination

Agglutination is the antibody mediated clumping of bacteria and viruses.

They are readily phagocytosed by macrophages.

Clumping is enhanced by IgM and IgA antibodies because they bind more than one antibody.

Agglutination is the antibody mediated clumping of bacteria and viruses.

They are readily phagocytosed by macrophages.

Clumping is enhanced by IgM and IgA antibodies because they bind more than one antibody.

3. Precipitation3. Precipitation

Precipitation is similar to agglutination in that it binds antigens.

Immobile aggregates are phagocytosed.

Precipitation is similar to agglutination in that it binds antigens.

Immobile aggregates are phagocytosed.

4. Opsonization4. Opsonization

Opsonization occurs when bound antibodies enhance macrophage attachment to microbes.

This increases the rate of phagocytosis.

Similar to viral neutralization.

Opsonization occurs when bound antibodies enhance macrophage attachment to microbes.

This increases the rate of phagocytosis.

Similar to viral neutralization.

Membrane Attack Complex

Membrane Attack Complex

Triggered by substances from the body’s innate defenses.

The MAC is triggered by the antigen-antibody response.

This complex forms pores in the membrane, and they allow H2O and ions to rush in and lyse an infected cell.

Triggered by substances from the body’s innate defenses.

The MAC is triggered by the antigen-antibody response.

This complex forms pores in the membrane, and they allow H2O and ions to rush in and lyse an infected cell.

Ways to Prevent Infection

Ways to Prevent Infection

There are 2 types of immunization:

1. Active immunity 2. Passive immunity

There are 2 types of immunization:

1. Active immunity 2. Passive immunity

1. Active Immunity1. Active Immunity

This is immunity conferred by a natural exposure to an infectious agent.

It also can develop following immunization.

This is immunity conferred by a natural exposure to an infectious agent.

It also can develop following immunization.

2. Passive Immunity2. Passive Immunity

Passive immunity results from the transfer of antibodies from an immune individual to someone who isn’t.

Transferred antibodies are immediately available to attack antigens to which they are specific.

Passive immunity results from the transfer of antibodies from an immune individual to someone who isn’t.

Transferred antibodies are immediately available to attack antigens to which they are specific.

Edward JennerEdward Jenner

English physician in the late 1700’s.

Noticed that milkmaids who had contracted cowpox were resistant to smallpox.

Took fluid from a cowpox sore and scratched the arm of a healthy farmboy with it.

When the body was later exposed to smallpox, he was immune.

English physician in the late 1700’s.

Noticed that milkmaids who had contracted cowpox were resistant to smallpox.

Took fluid from a cowpox sore and scratched the arm of a healthy farmboy with it.

When the body was later exposed to smallpox, he was immune.

BloodBlood

Blood type is inherited. A case of multiple alleles. Transcription and translation result in the production of an enzyme that adds carbohydrates to the surface of RBCs.

A and B are codominant, (IA, IB). O is recessive, (ii). Rh factor is also genetic and elicits an immune response.

Blood type is inherited. A case of multiple alleles. Transcription and translation result in the production of an enzyme that adds carbohydrates to the surface of RBCs.

A and B are codominant, (IA, IB). O is recessive, (ii). Rh factor is also genetic and elicits an immune response.

Blood TypesBlood Types

People who have a particular blood type do not produce antibodies against that blood type.

They do make antibodies against other types of blood. For example: People who are type A, do not make anti-A antibodies. They do, however, make antibodies against other blood types.

People who have a particular blood type do not produce antibodies against that blood type.

They do make antibodies against other types of blood. For example: People who are type A, do not make anti-A antibodies. They do, however, make antibodies against other blood types.

Incompatibilities of Blood


The incompatibilities of blood are due to the presence of antigens and antibodies.

Antigens: Are on the surface of the plasma membrane of the erythrocyte.

Antibodies: Are found in the blood plasma.

The incompatibilities of blood are due to the presence of antigens and antibodies.

Antigens: Are on the surface of the plasma membrane of the erythrocyte.

Antibodies: Are found in the blood plasma.



Incompatibilities are due to the interactions of antigens and antibodies.

Whenever the antigen and antibody are present in the same blood, clotting will occur.

Incompatibilities are due to the interactions of antigens and antibodies.

Whenever the antigen and antibody are present in the same blood, clotting will occur.

Normal BloodNormal Blood

Normally in blood, an antigen is present and its corresponding antibody is absent.

Normally in blood, an antigen is present and its corresponding antibody is absent.

The ABO Blood GroupThe ABO Blood Group

The presence or absence of the A and B antigens and antibodies determines the blood type.

The presence or absence of the A and B antigens and antibodies determines the blood type.

Type A BloodType A Blood

Type A blood exhibits the A antigen on its red cell membranes.

The plasma contains anti-B antibody.

Type A blood exhibits the A antigen on its red cell membranes.

The plasma contains anti-B antibody.

Type B BloodType B Blood

Contains the Type B antigen. The plasma contains anti-A antibody.

Contains the Type B antigen. The plasma contains anti-A antibody.

Type AB BloodType AB Blood

Contains both A and B antigens on the surface of the erythrocytes.

Neither anti-A nor anti-B antibodies are present.

Contains both A and B antigens on the surface of the erythrocytes.

Neither anti-A nor anti-B antibodies are present.

Type O BloodType O Blood

Neither A nor B antigens are present.

Both antibodies, anti-A and anti-B are present.

Neither A nor B antigens are present.

Both antibodies, anti-A and anti-B are present.

The Rh Blood GroupThe Rh Blood Group

There are numerous Rh antigens, and most are of little clinical importance.

D-antigen, commonly referred to as Rh factor, is strongly antigenic.

When Rh factor is present on an RBC: Rh+

When Rh factor is absent: Rh-

There are numerous Rh antigens, and most are of little clinical importance.

D-antigen, commonly referred to as Rh factor, is strongly antigenic.

When Rh factor is present on an RBC: Rh+

When Rh factor is absent: Rh-


Rh antibodies are not normally present in Rh-negative individuals.

Exposure to Rh-positive blood will cause the production of antibodies to Rh.

No immediate problem. The next time Rh-positive blood is given, the positive cells get destroyed.

Rh antibodies are not normally present in Rh-negative individuals.

Exposure to Rh-positive blood will cause the production of antibodies to Rh.

No immediate problem. The next time Rh-positive blood is given, the positive cells get destroyed.


2 common clinical problems associated with Rh:

Blood transfusions. Child birth.

2 common clinical problems associated with Rh:

Blood transfusions. Child birth.

Rh and Blood TransfusionsRh and Blood Transfusions

Rh-positive blood should not be given to Rh-negative individuals.

Assuming ABO compatibility, Rh- can be administered to Rh+.

Rh-positive blood should not be given to Rh-negative individuals.

Assuming ABO compatibility, Rh- can be administered to Rh+.

Rh and ChildbirthRh and Childbirth

First time Rh-negative mothers who bear an Rh-positive fetus usually have no complications.

During birth, the placenta is destroyed allowing fetal and maternal blood to mix.

Mom’s immune system now produces antibodies to the Rh+ blood.

First time Rh-negative mothers who bear an Rh-positive fetus usually have no complications.

During birth, the placenta is destroyed allowing fetal and maternal blood to mix.

Mom’s immune system now produces antibodies to the Rh+ blood.


If mom gets pregnant again with another Rh-positive fetus the blood we have problems.

Antibodies can cross the placenta and attack the fetal RBCs.

Erythroblastosis fetalis results from clotting in the fetus.

If mom gets pregnant again with another Rh-positive fetus the blood we have problems.

Antibodies can cross the placenta and attack the fetal RBCs.

Erythroblastosis fetalis results from clotting in the fetus.


Administering RhoGAM (Rh antibodies) around the 7th month of pregnancy and within 72 hours of delivery of an Rh+ child greatly reduces the chance of erythroblastosis fetalis in the future.

Administering RhoGAM (Rh antibodies) around the 7th month of pregnancy and within 72 hours of delivery of an Rh+ child greatly reduces the chance of erythroblastosis fetalis in the future.


The Rh antibodies react with any Rh+ blood that may be in mom’s bloodstream.

This usually prevents an increase in the number of maternal Rh antibodies.

The Rh antibodies react with any Rh+ blood that may be in mom’s bloodstream.

This usually prevents an increase in the number of maternal Rh antibodies.

AllergiesAllergies

These are exaggerated responses to certain antigens.

The most common allergies involve antibodies of the IgE class.

When plasma cells secrete IgE antibodies specific for antigens on the surface of pollen grains, hay fever results.

These are exaggerated responses to certain antigens.

The most common allergies involve antibodies of the IgE class.

When plasma cells secrete IgE antibodies specific for antigens on the surface of pollen grains, hay fever results.

AllergiesAllergies

Some antibodies are attached to mast cells which are found in connective tissue.

When allergens enter the body, they become attached to the mast cell-IgE association.

This triggers the release of histamine and other inflammatory substances.

Some antibodies are attached to mast cells which are found in connective tissue.

When allergens enter the body, they become attached to the mast cell-IgE association.

This triggers the release of histamine and other inflammatory substances.

AllergiesAllergies

Histamine causes dilation and increased permeability of small blood vessels.

This causes the common symptoms of allergy responses.

Histamine causes dilation and increased permeability of small blood vessels.

This causes the common symptoms of allergy responses.

Documents

Chapter 43 The Immune System. Protection From Invaders Your body has a variety of mechanisms to protect it from invasion. 1. The skin 2. Mucous