ImmunitImmunityy

PathogenPathogen“Path” = disease “ogen” = generating“Path” = disease “ogen” = generating

A pathogen is something that causes A pathogen is something that causes disease.disease.

A biological pathogen is a bacterium, A biological pathogen is a bacterium, virus, fungi, yeast, protozoa, worms, virus, fungi, yeast, protozoa, worms, etc.etc.

A non-biological pathogen can be a A non-biological pathogen can be a toxic chemical, asbestos, etc.toxic chemical, asbestos, etc.

Usually, the term “pathogen” refers to Usually, the term “pathogen” refers to a biological pathogen.a biological pathogen.

Sizes of PathogensSizes of Pathogens Bacteria are so small that hundreds of them Bacteria are so small that hundreds of them

can fit inside one white blood cell. can fit inside one white blood cell. However, bacteria usually do not invade body However, bacteria usually do not invade body

cells. They live between the cells of the body, cells. They live between the cells of the body, using up nutrients in the area, and they cause using up nutrients in the area, and they cause harm by secreting toxins.harm by secreting toxins.

Viruses are so small that thousands of them Viruses are so small that thousands of them can fit inside the NUCLEUS of one white blood can fit inside the NUCLEUS of one white blood cell.cell. They always try to invade body cells because they They always try to invade body cells because they

need a piece of our DNA or RNA in order to need a piece of our DNA or RNA in order to replicate.replicate.

When a body cell has been invaded by a virus, the When a body cell has been invaded by a virus, the entire cell must be killed by a white blood cell.entire cell must be killed by a white blood cell.

AntigenAntigen An An antigenantigen is anything that causes is anything that causes

an immune response, which isn't an immune response, which isn't necessarily a biological pathogen necessarily a biological pathogen (disease-causing organism). (disease-causing organism).

A non-biological antigen can be A non-biological antigen can be pollen, dust, grass, or anything that a pollen, dust, grass, or anything that a person is allergic to.person is allergic to.

Pollen can be an antigen to a person Pollen can be an antigen to a person with allergies, but it is not an antigen with allergies, but it is not an antigen to a person without allergies, because to a person without allergies, because no immune response was launched.no immune response was launched.

LEUKOCYTES LEUKOCYTES (White blood (White blood cells)cells)

all fight infectionall fight infection BASOPHILSBASOPHILS

– MAST CELLMAST CELL EOSINOPHILSEOSINOPHILS NEUTROPHILSNEUTROPHILS MONOCYTESMONOCYTES

– MACROPHAGESMACROPHAGES LYMPHOCYTESLYMPHOCYTES

– B CELLSB CELLS– T CELLST CELLS

Basophils – only about Basophils – only about 0.5% of all leukocytes0.5% of all leukocytes– Granules secrete Granules secrete

histamineshistamines (vasodilation; (vasodilation; more WBCs can get to the more WBCs can get to the infection site)infection site)

– Antihistamines interfere Antihistamines interfere with the function of with the function of basophils.basophils.

– Mast Cell: a basophil that Mast Cell: a basophil that leaves the blood vessel leaves the blood vessel and enters the tissues. and enters the tissues.

BASOPHILSBASOPHILS

EosinophilsEosinophils

Eosinophils – compose Eosinophils – compose 1-4% of all WBCs1-4% of all WBCs– Play roles in: Play roles in:

Ending Ending allergic allergic reactionsreactions, , parasitic parasitic infectionsinfections

During these conditions During these conditions they increase in they increase in numbers: eosinophilianumbers: eosinophilia

(too many is ___philia(too many is ___philia too few is ___penia)too few is ___penia)

Neutrophils – most Neutrophils – most numerous WBCnumerous WBC

First to respond to First to respond to infectioninfection– Phagocytize and destroy Phagocytize and destroy

bacteriabacteria– Also destroy bacterial Also destroy bacterial

toxins in body fluidstoxins in body fluids– Nucleus – has two to six Nucleus – has two to six

lobeslobes

NeutrophilsNeutrophils

NeutrophilsNeutrophils Neutrophils are the white blood cells Neutrophils are the white blood cells

that contribute to immunity mainly by that contribute to immunity mainly by engulfing BACTERIA and foreign bodies engulfing BACTERIA and foreign bodies (thorns, dirt, etc) in a process called (thorns, dirt, etc) in a process called phagocytosis. phagocytosis.

They release the contents of their They release the contents of their lysosomes onto the invader, dissolving lysosomes onto the invader, dissolving it.it.

When a bacterium has a capsule, it When a bacterium has a capsule, it makes it hard to phagocytize, so the makes it hard to phagocytize, so the neutrophil requires opsonization by neutrophil requires opsonization by antibodies.antibodies.

OpsonizationOpsonization Some bacteria have evolved a slippery Some bacteria have evolved a slippery

capsule around them as a defense capsule around them as a defense against phagocytosis. The neutrophil against phagocytosis. The neutrophil cannot engulf this type of bacteria. cannot engulf this type of bacteria. Neither can a macrophage.Neither can a macrophage.

When an antibody attaches to this type When an antibody attaches to this type of bacteria, the neutrophil can now of bacteria, the neutrophil can now grab onto the antibody like a handle, grab onto the antibody like a handle, enabling it to phagocytize the bacteria.enabling it to phagocytize the bacteria.

This process of facilitation of This process of facilitation of phagocytosis is called opsonization.phagocytosis is called opsonization.

When an invading bacteria has the antibody When an invading bacteria has the antibody attached to its cell membrane, the entire attached to its cell membrane, the entire structure is now called an antigen-antibody structure is now called an antigen-antibody complex.complex.

If a bacterium does not have a capsule, the If a bacterium does not have a capsule, the neutrophil can destroy it without opsonization. neutrophil can destroy it without opsonization. The antibody can also destroy the bacterium by The antibody can also destroy the bacterium by itself by popping the cell membrane.itself by popping the cell membrane.

But when a capsule is present, the neutrophil But when a capsule is present, the neutrophil and antibody work best together.and antibody work best together.

Neutrophils are also the ones that Neutrophils are also the ones that primarily destroy the dissolved toxins that primarily destroy the dissolved toxins that bacteria secrete into body fluids.bacteria secrete into body fluids.

MonocytesMonocytes Comprise about 5% of all Comprise about 5% of all

WBC’s.WBC’s. Like neutrophils, they Like neutrophils, they

phagocytize (eat) bacteria, old phagocytize (eat) bacteria, old cells, and foreign bodies.cells, and foreign bodies. They They have more types of lysosome have more types of lysosome enzymes than neutrophils so enzymes than neutrophils so they are better at killing they are better at killing difficult pathogens.difficult pathogens.

They also use antibodies for They also use antibodies for opsonization.opsonization.

When they leave the When they leave the bloodstream and enter the bloodstream and enter the tissues, they are calledtissues, they are called MACROPHAGES.MACROPHAGES.

WBC’s leave the blood vessel WBC’s leave the blood vessel to enter the tissuesto enter the tissues

What’s the Difference between Neutrophils What’s the Difference between Neutrophils and Monocytes/Macrophages?and Monocytes/Macrophages?

There are 10x more neutrophils in the There are 10x more neutrophils in the bloodstreambloodstream than monocytes/Macrophages. than monocytes/Macrophages. Consider neutrophils to Consider neutrophils to be the most numerous white blood cell.be the most numerous white blood cell.

However, there are more macrophages in the However, there are more macrophages in the tissuestissues of of the body. They are everywhere! the body. They are everywhere!

Neutrophils live only a few days. Monocytes/Macrophages Neutrophils live only a few days. Monocytes/Macrophages live a few months. Lymphocytes live for years.live a few months. Lymphocytes live for years.

Monocytes/Macrophages are larger and slower than Monocytes/Macrophages are larger and slower than neutrophils, but they can phagocytize larger organisms neutrophils, but they can phagocytize larger organisms and more of them. and more of them.

Neutrophils usually just phagocytize bacteria until they Neutrophils usually just phagocytize bacteria until they die. Macrophages phagocytize and then take pieces of die. Macrophages phagocytize and then take pieces of the dead bacteria and present them to lymphocytes so a the dead bacteria and present them to lymphocytes so a larger immune response can occur.larger immune response can occur.

Differences in FunctionDifferences in Function There are two types of phagocytes: Neutrophils There are two types of phagocytes: Neutrophils

and macrophages.and macrophages.– Neutrophils and macrophages both mainly Neutrophils and macrophages both mainly

function by phagocytizing bacteria (not function by phagocytizing bacteria (not viruses). viruses).

Lymphocytes are mostly needed to kill off body Lymphocytes are mostly needed to kill off body cells infected by cells infected by viruses.viruses.

Differences in FunctionDifferences in Function Neutrophils just phagocytize bacteria and secrete Neutrophils just phagocytize bacteria and secrete

chemicals to recruit more white blood cells to the site.chemicals to recruit more white blood cells to the site. Unlike neutrophils, macrophages have Unlike neutrophils, macrophages have surface surface

receptorsreceptors; these "recognize" the surface of the ; these "recognize" the surface of the pathogen’s cell membrane. pathogen’s cell membrane.

Macrophages phagocytize the bacteria, pop their Macrophages phagocytize the bacteria, pop their lysosomes onto it, and dissolve it, except for some lysosomes onto it, and dissolve it, except for some pieces of the bacteria’s cell membrane. pieces of the bacteria’s cell membrane.

The macrophage places these pieces of bacteria on The macrophage places these pieces of bacteria on its own cell membrane, and finds a lymphocyte to its own cell membrane, and finds a lymphocyte to present it to.present it to.

Differences in FunctionDifferences in Function

Macrophages present these pieces to T cell Macrophages present these pieces to T cell lymphocytes and to B cells lymphocytes.lymphocytes and to B cells lymphocytes.

The lymphocyte feels the shape of the bacteria The lymphocyte feels the shape of the bacteria pieces on top of the macrophage, (this is called pieces on top of the macrophage, (this is called “antigen presentation”) and the lymphocyte can “antigen presentation”) and the lymphocyte can then launch an attack on the rest of the bacteria then launch an attack on the rest of the bacteria still alive in the body.still alive in the body.

In this way, the macrophage recruits even more In this way, the macrophage recruits even more lymphocytes to join the war.lymphocytes to join the war.

So, what is a lymphocyte?So, what is a lymphocyte?

20–45% of WBCs20–45% of WBCs– The most important cells of The most important cells of

the immune systemthe immune system– There are two types of There are two types of

lymphocytes; one type is lymphocytes; one type is effective in fighting infectious effective in fighting infectious organisms like body cells organisms like body cells infected with infected with virusesviruses

– Both types of lymphocytes act Both types of lymphocytes act against a against a specific foreign specific foreign molecule (antigen)molecule (antigen)

LymphocytesLymphocytes

Two main classes of lymphocyte Two main classes of lymphocyte – B cells – Originate in the bone marrow, B cells – Originate in the bone marrow,

mature into plasma cells. mature into plasma cells. A mature A mature plasma cell fights infection by plasma cell fights infection by producing antibodiesproducing antibodies

– T cells – Originate in the thymus gland. T cells – Originate in the thymus gland. They attack foreign cells directly They attack foreign cells directly ((including organ transplants!). including organ transplants!). They can also kill viruses.They can also kill viruses.

LymphocytesLymphocytes

B cells – mature into plasma cellsB cells – mature into plasma cells Plasma cells secrete antibodies; Plasma cells secrete antibodies;

the plasma cell’s antibodies are the plasma cell’s antibodies are what kills the attacking cell.what kills the attacking cell.

Antibodies attack in two ways:Antibodies attack in two ways:– They attach to bacteria and pop the cell They attach to bacteria and pop the cell

membranemembrane– They attach to encapsulated bacteria to They attach to encapsulated bacteria to

help neutrophils and macrophages to help neutrophils and macrophages to phagocytize them.phagocytize them.

LymphocytesLymphocytes

MononucleosisMononucleosis: Epstein Barr virus : Epstein Barr virus attacks B lymphocytes. It is attacks B lymphocytes. It is characterized by inflammation of characterized by inflammation of lymph vessels (lymphangitis).lymph vessels (lymphangitis).

– LymphangitisLymphangitis: lymph vessel : lymph vessel inflammation; usually from infection.inflammation; usually from infection.

Infected lymphocytes have a Infected lymphocytes have a

characteristic scalloped characteristic scalloped

edge where they touchedge where they touch

RBC’sRBC’s

Disorder of B-cell Disorder of B-cell LymphocytesLymphocytes

Function of a B LymphocyteFunction of a B Lymphocyte

Figure 17.6b

T cells – coordinate the immune response by T cells – coordinate the immune response by recruiting other white blood cells. recruiting other white blood cells.

They can directly destroy bacteria by popping They can directly destroy bacteria by popping their cell membrane.their cell membrane.

T cells can also directly destroy foreign cells by T cells can also directly destroy foreign cells by popping the cell membrane. popping the cell membrane.

They do not need to phagocytize the invading They do not need to phagocytize the invading cell. They do not need the assistance of cell. They do not need the assistance of antibodies.antibodies.

T-cells can therefore kill a body cell that has T-cells can therefore kill a body cell that has become infected with viruses.become infected with viruses.

T-cell LymphocytesT-cell Lymphocytes

T-CellT-Cell

T cells are the cells that attack T cells are the cells that attack organ transplants!organ transplants!

Immunosuppression drugs are designed to Immunosuppression drugs are designed to inhibit the action of T cells. inhibit the action of T cells.

T cells are attacked by the HIV (AIDS) T cells are attacked by the HIV (AIDS) virus.virus.

The thymus gland secrets certain The thymus gland secrets certain hormones which can cause T cells to hormones which can cause T cells to become immunocompetent (makes become immunocompetent (makes the cells mature and start to work)the cells mature and start to work)

T-cell LymphocytesT-cell Lymphocytes

T CellsT CellsThere are several types of T cells. The main types areThere are several types of T cells. The main types are Cytotoxic (Killer) T cellsCytotoxic (Killer) T cells

– Go out and directly kill bacteria or infected host cells Go out and directly kill bacteria or infected host cells Helper T cellsHelper T cells

– Release chemicals called “cytokines” to call in more Release chemicals called “cytokines” to call in more white blood cells of all types to join in the war. They also white blood cells of all types to join in the war. They also present the macrophage’s antigen to a B cell, which present the macrophage’s antigen to a B cell, which causes it to produce antibodies against that particular causes it to produce antibodies against that particular bacteria. The B cell is now called a plasma cell bacteria. The B cell is now called a plasma cell

Suppressor T cellsSuppressor T cells– Stop the immune process when it is over, and also "tell" Stop the immune process when it is over, and also "tell"

some plasma cells to "remember" how to destroy that some plasma cells to "remember" how to destroy that specific pathogen. Those plasma B-cells are then called specific pathogen. Those plasma B-cells are then called Memory B-Cells. They can react to the same pathogen Memory B-Cells. They can react to the same pathogen faster, the next time it invades because Memory B-cells faster, the next time it invades because Memory B-cells already have the proper antibodies stored up for that already have the proper antibodies stored up for that pathogen.pathogen.

Killer T-Killer T-CellCell

Virus-Infected CellVirus-Infected Cell

Function of a T- LymphocyteFunction of a T- Lymphocyte

Figure 17.6a

SummarySummary A pathogen somehow gets past the body's physical A pathogen somehow gets past the body's physical

and chemical barriers and the inflammation response. and chemical barriers and the inflammation response. The pathogen is engulfed by a macrophage (or The pathogen is engulfed by a macrophage (or

neutrophil). neutrophil). The macrophage releases the contents of its The macrophage releases the contents of its

lysosomes onto the bacterium and dissolves most of it. lysosomes onto the bacterium and dissolves most of it. There are still some pieces of the bacterium’s cell There are still some pieces of the bacterium’s cell membrane left. The macrophage then forces the membrane left. The macrophage then forces the surface proteins of the bacterium (antigens) to it's own surface proteins of the bacterium (antigens) to it's own cell surface. cell surface.

Helper T-Cells touch these surface antigens, make a Helper T-Cells touch these surface antigens, make a copy of their shape, and present them to B-cells to copy of their shape, and present them to B-cells to make antibodies against them.make antibodies against them.

SummarySummary These Helper T-Cells begin to multiply and have two main roles. These Helper T-Cells begin to multiply and have two main roles. The first is to activate B-Cells and "tell" them how to neutralize the The first is to activate B-Cells and "tell" them how to neutralize the

pathogen by presenting the pieces of the bacterium cell membrane so pathogen by presenting the pieces of the bacterium cell membrane so the B-cells can turn into plasma cells which make the antibodies. the B-cells can turn into plasma cells which make the antibodies. – The B-Cells (now called Plasma cells because they have been The B-Cells (now called Plasma cells because they have been

activated) begin to multiply and produce the antibodies to activated) begin to multiply and produce the antibodies to neutralize this specific pathogen. neutralize this specific pathogen.

The second role of Helper T-Cells is to activate the Killer T-Cells by The second role of Helper T-Cells is to activate the Killer T-Cells by secreting cytokines. secreting cytokines.

Killer T-Cells can either destroy the pathogen itself (bacteria), or Killer T-Cells can either destroy the pathogen itself (bacteria), or destroy the entire body cell which is infected (viruses). destroy the entire body cell which is infected (viruses).

When the immune response is over, Suppressor T-Cells stop the When the immune response is over, Suppressor T-Cells stop the process and also "tell" some B-Cells (plasma cells) to "remember" how process and also "tell" some B-Cells (plasma cells) to "remember" how to destroy that specific pathogen.to destroy that specific pathogen.

Those B-cells (plasma cells) now become Memory B-Cells. Those B-cells (plasma cells) now become Memory B-Cells.

AntibodiesAntibodies

AntibodiesAntibodies (also known as (also known as immunoglobulinsimmunoglobulins, abbreviated , abbreviated IgIg) are ) are proteins made by plasma cells.proteins made by plasma cells.

They are used to identify and neutralize They are used to identify and neutralize foreign objects, such as bacteria and foreign objects, such as bacteria and viruses. viruses.

They are typically made of basic structural They are typically made of basic structural units—each with two large heavy chains units—each with two large heavy chains and two small light chains—to form a unit and two small light chains—to form a unit shaped like the letter “Y”shaped like the letter “Y”

A Typical A Typical AntibodyAntibody

The tips of the “Y” have receptors that are specific for a particular antigen.

The stem of the “Y” can be grasped by a phagocyte.

AntibodiesAntibodies The small region at the tip of the protein is The small region at the tip of the protein is

extremely variable, allowing millions of extremely variable, allowing millions of antibodies with slightly different tip antibodies with slightly different tip structures, or antigen binding sites, to exist. structures, or antigen binding sites, to exist.

This region is known as the hypervariable This region is known as the hypervariable region. Each of these variants can bind to a region. Each of these variants can bind to a different target, known as an antigen.different target, known as an antigen.

This huge diversity of antibodies allows the This huge diversity of antibodies allows the immune system to recognize an equally immune system to recognize an equally wide diversity of antigens. wide diversity of antigens.

AntibodiesAntibodies Some of these “Y” shaped units Some of these “Y” shaped units

exist by themselves exist by themselves (monomers)(monomers)

Some are in pairs (dimers)Some are in pairs (dimers) Some are in a cluster of five Some are in a cluster of five

(pentamers)(pentamers) There are five different antibody There are five different antibody

types , which perform different types , which perform different roles, and help direct the roles, and help direct the appropriate immune response appropriate immune response for each different type of for each different type of foreign object they encounter.foreign object they encounter.

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Precipitation/agglutination#1 #3#2

Types of Types of AntibodieAntibodie

ss

IgD – initiation of immune response

IgE – stimulates allergic reactions, good forworm infections

IgG – highest concentration in blood, highestamounts in most secondary responses, crosses the placenta

IgA – secretory Ig, found in secretions,highest concentration in body

IgM – produced first, best at C’ activation

J-Protein is what attaches the antibody segments

Neutrophil

Macrophage(Monocyte in

bloodstream)

B-CellKiller

T-CellHelper T-Cell

Suppressor T-Cell

Plasma Cell

Lymphocytes

Phagocytosis

Bacteria

Virus

Presentation

Y Y

YAntibodies

Y

Y

Pops the cell

Capsule

Cytokines

Pops the cell

STOP

Opsonization

Bacteria

Presentation

IMMUNITYIMMUNITY

Most people are sick more often as Most people are sick more often as children than as adults in their 20s children than as adults in their 20s through 30s because we build up through 30s because we build up many varieties of memory many varieties of memory lymphocytes during childhood, lymphocytes during childhood, providing immunity from more and providing immunity from more and more antigens during adulthood.more antigens during adulthood.

Myasthenia gravisMyasthenia gravis

Myasthenia gravisMyasthenia gravis (MG): autoimmune (MG): autoimmune disease where antibodies destroy or disease where antibodies destroy or block receptors for acetylcholine, a block receptors for acetylcholine, a neurotransmitter. neurotransmitter.

Causes muscle paralysis. Causes muscle paralysis. First attacks small muscles especially First attacks small muscles especially

those that keep eyes open; will spread those that keep eyes open; will spread to diaphragm to diaphragm death. death.

To stave off effects, do thymectomy. To stave off effects, do thymectomy.

AspirinAspirin

One baby aspirin a day can help prevent One baby aspirin a day can help prevent blood clots.blood clots.

It blocks the ability of an enzyme called It blocks the ability of an enzyme called COX (cyclo-oxidase) to cleave arachidonic COX (cyclo-oxidase) to cleave arachidonic acid into a molecule called a prostaglandin.acid into a molecule called a prostaglandin.

Prostaglandins are needed for inflammatory Prostaglandins are needed for inflammatory reactions and for making clotting factors.reactions and for making clotting factors.

COX inhibitors, such as aspirin, block pain COX inhibitors, such as aspirin, block pain from inflammation, but they also INCREASE from inflammation, but they also INCREASE blood clotting time.blood clotting time.

Fig. 9-1Hematopoiesis

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Life span, from longest-Life span, from longest-lived to shortest-lived:lived to shortest-lived:

LymphocytesLymphocytes ErythrocytesErythrocytes PlateletsPlatelets NeutrophilsNeutrophils

TermsTerms

Excess neutrophils: neutrophiliaExcess neutrophils: neutrophilia Few neutrophils: neutropeniaFew neutrophils: neutropenia

Excess platelets: thrombocytophiliaExcess platelets: thrombocytophilia Few platelets: thrombocytopeniaFew platelets: thrombocytopenia

WBC Count WBC Count White blood cell (WBC) White blood cell (WBC) count is a count of the count is a count of the

actual number of white blood cells per volume of actual number of white blood cells per volume of blood. Both increases and decreases can be blood. Both increases and decreases can be significant. significant.

White blood cell differential White blood cell differential looks at the types of looks at the types of white blood cells present. There are five different white blood cells present. There are five different types of white blood cells, each with its own function types of white blood cells, each with its own function in protecting us from infection. The differential in protecting us from infection. The differential classifies a person's white blood cells into each type: classifies a person's white blood cells into each type: neutrophils (also known as segs, PMNs, granulocytes, neutrophils (also known as segs, PMNs, granulocytes, grans), lymphocytes, monocytes, eosinophils, and grans), lymphocytes, monocytes, eosinophils, and basophils. basophils.

BLOOD TYPING: BLOOD TYPING: The ABO The ABO SYSTEMSYSTEM

Blood typing is the technique for Blood typing is the technique for determining which specific protein determining which specific protein type is present on RBCs. type is present on RBCs.

Only certain types of blood Only certain types of blood transfusions are safe because the transfusions are safe because the outer membranes of the red blood outer membranes of the red blood cells carry certain types of proteins cells carry certain types of proteins that another person’s body will think that another person’s body will think is a foreign body and reject it. is a foreign body and reject it.

BLOOD TYPINGBLOOD TYPING

These proteins are called antigens (something These proteins are called antigens (something that causes an allergic reaction). There are two that causes an allergic reaction). There are two types of blood antigens: Type A and Type B.types of blood antigens: Type A and Type B.

A person with Type A antigens on their blood A person with Type A antigens on their blood cells have Type A blood.cells have Type A blood.

A person with Type B antigens have Type B A person with Type B antigens have Type B blood.blood.

A person with both types has type AB blood.A person with both types has type AB blood. A person with neither antigen has type O blood.A person with neither antigen has type O blood.

BLOOD TYPINGBLOOD TYPING

If a person with type A blood gets a If a person with type A blood gets a transfusion of type B antigens (from Type B or transfusion of type B antigens (from Type B or Type AB, the donated blood will clump in Type AB, the donated blood will clump in masses (coagulation), and the person will die.masses (coagulation), and the person will die.

The same is true for a type B person getting The same is true for a type B person getting type A or AB blood.type A or AB blood.

Type O- blood is called the universal donor, Type O- blood is called the universal donor, because there are no antigens, so that blood because there are no antigens, so that blood can be donated to anyone. can be donated to anyone.

Type AB+ blood is considered the universal Type AB+ blood is considered the universal acceptor, because they can use any other type acceptor, because they can use any other type of blood. This blood type is fairly rare.of blood. This blood type is fairly rare.

The rarest blood type is AB negative.The rarest blood type is AB negative.

RH FACTORRH FACTOR

There is another term that follows There is another term that follows the blood type. The term is “positive” the blood type. The term is “positive” or “negative”. This refers to the or “negative”. This refers to the presence of another type of protein, presence of another type of protein, called the Rh factor. A person with called the Rh factor. A person with type B blood and has the Rh factor is type B blood and has the Rh factor is called B positive.called B positive.

A person with type B blood and no Rh A person with type B blood and no Rh factor is called B negative.factor is called B negative.

RH FACTORRH FACTOR

The reason this is so important is that if The reason this is so important is that if an Rh- mother has an Rh+ fetus in her an Rh- mother has an Rh+ fetus in her womb (from an Rh+ father), her womb (from an Rh+ father), her antibodies will attack the red blood antibodies will attack the red blood cells of the fetus because her body cells of the fetus because her body detects the Rh protein on the baby’s detects the Rh protein on the baby’s red blood cells and thinks they are red blood cells and thinks they are foreign objects. This is called Hemolytic foreign objects. This is called Hemolytic Disease of the Newborn (HDN).Disease of the Newborn (HDN).

HDNHDN This can be prevented if the doctor This can be prevented if the doctor

knows the mother is Rh- and the father is knows the mother is Rh- and the father is Rh+, because that means the baby has a Rh+, because that means the baby has a 50% chance of being Rh+ like the father. 50% chance of being Rh+ like the father.

Therefore, anytime a mother is Rh-, even Therefore, anytime a mother is Rh-, even if the mother says the father is Rh-, you if the mother says the father is Rh-, you can’t be sure who the father is, so they can’t be sure who the father is, so they will proceed as though the baby may be will proceed as though the baby may be Rh +. Rh +.

They will give her an injection of a They will give her an injection of a medicine (Rhogam) that will prevent her medicine (Rhogam) that will prevent her immune system from attacking the baby.immune system from attacking the baby.

RhogamRhogam Rhogam is given at 18 weeks into the pregnancy Rhogam is given at 18 weeks into the pregnancy

and again within 72 hours after giving birth.and again within 72 hours after giving birth. It is usually given within 2 hours after giving birth It is usually given within 2 hours after giving birth

since you can’t trust the patient to return after they since you can’t trust the patient to return after they leave the hospital.leave the hospital.

The first baby is not at risk; during the first birth (or The first baby is not at risk; during the first birth (or miscarriage), the placenta tears away and that’s miscarriage), the placenta tears away and that’s when the baby’s blood cells get into the mother’s when the baby’s blood cells get into the mother’s bloodstream.bloodstream.

She then forms antibodies against the Rh factor, She then forms antibodies against the Rh factor, which are ready to attack the second fetus.which are ready to attack the second fetus.

The baby does not make the Rh factor until about The baby does not make the Rh factor until about 18 weeks into the pregnancy.18 weeks into the pregnancy.

IMMUNE SYSTEMIMMUNE SYSTEM

INFLAMMATORY REACTION: INFLAMMATORY REACTION: When you When you get stuck by a thorn or have an infected get stuck by a thorn or have an infected cut, the body goes through a series of cut, the body goes through a series of events called an inflammatory reaction. events called an inflammatory reaction.

Four outward signs:Four outward signs:– Redness (erythema or rubor)Redness (erythema or rubor)– Heat (calor)Heat (calor)– Swelling (edema)Swelling (edema)– Pain (dolor)Pain (dolor)

INFLAMMATORY INFLAMMATORY REACTIONREACTION

RednessRedness is caused from the blood vessels is caused from the blood vessels dilating to allow more blood flow to the area. dilating to allow more blood flow to the area. Within the blood are platelets to clot the blood, Within the blood are platelets to clot the blood, proteins to repair the damage, and macrophages, proteins to repair the damage, and macrophages, which are white blood cells that eat up the which are white blood cells that eat up the foreign body, bacteria, or the dead cells.foreign body, bacteria, or the dead cells.

HeatHeat is caused because of the extra amount of is caused because of the extra amount of warm blood flow to the area.warm blood flow to the area.

SwellingSwelling is caused from the plasma that leaks is caused from the plasma that leaks out of the swollen blood vessels.out of the swollen blood vessels.

PainPain is caused from the pressure of the extra is caused from the pressure of the extra fluid pressing on nerves in the area. fluid pressing on nerves in the area.

ADAPTIVE IMMUNITYADAPTIVE IMMUNITY

Two types of Adaptive Two types of Adaptive ImmunityImmunity– ACTIVE immunityACTIVE immunity

Naturally AcquiredNaturally Acquired Artificially AcquiredArtificially Acquired

– PASSIVE PASSIVE immunityimmunity Naturally Naturally

AcquiredAcquired Artificially Artificially

AcquiredAcquiredYou can also think of it this way

Active ImmunityActive Immunity

Naturally AcquiredNaturally Acquired– The body is naturally exposed to an The body is naturally exposed to an

infectious agent and launches an infectious agent and launches an immune reactionimmune reaction

Artificially AcquiredArtificially Acquired– The person is injected with a weakened The person is injected with a weakened

(attenuated) or killed organism, as (attenuated) or killed organism, as found in a vaccinationfound in a vaccination

Naturally Acquired Naturally Acquired Active ImmunityActive Immunity

This is when the body is exposed to an This is when the body is exposed to an infectious agent and the body has to work infectious agent and the body has to work to produce antibodies which specifically to produce antibodies which specifically attack that infectious agent. attack that infectious agent.

The white blood cells secrete these The white blood cells secrete these antibodies which will continue to circulate antibodies which will continue to circulate sometimes for years, ready to attack that sometimes for years, ready to attack that type of bacteria and cause them to pop type of bacteria and cause them to pop like a balloon before the body can become like a balloon before the body can become sick. sick.

Naturally AcquiredNaturally AcquiredActive ImmunityActive Immunity

– You catch a cold and eventually get better. You You catch a cold and eventually get better. You can never get the same cold virus twice can never get the same cold virus twice because you will have become immune to it. because you will have become immune to it. Your next cold is from a different virus. There Your next cold is from a different virus. There are hundreds of thousands of cold viruses; are hundreds of thousands of cold viruses; that’s why there is no cure for the common that’s why there is no cure for the common cold.cold.

– Another example is when an unvaccinated Another example is when an unvaccinated child is exposed to the measles at school and child is exposed to the measles at school and gets the disease, but never gets the disease gets the disease, but never gets the disease again. again.

However, there are some diseases that you However, there are some diseases that you don’t want to get, even once, such as polio, don’t want to get, even once, such as polio, diphtheria, tetanus, and influenza, because diphtheria, tetanus, and influenza, because the first exposure could kill or disable you. the first exposure could kill or disable you.

For these diseases, we have vaccines which For these diseases, we have vaccines which are made of those organisms which have been are made of those organisms which have been altered (attenuated) so that the body altered (attenuated) so that the body recognizes them as foreign, but they can’t recognizes them as foreign, but they can’t cause disease. cause disease.

That way, if the person is exposed to the real That way, if the person is exposed to the real organism later, the antibodies are already organism later, the antibodies are already there to kill it off without the body getting sick. there to kill it off without the body getting sick.

Artificially Acquired Artificially Acquired Active ImmunityActive Immunity

An example is when a child is vaccinated An example is when a child is vaccinated against measles as a baby, so when he against measles as a baby, so when he gets to school and is exposed to the gets to school and is exposed to the disease, he doesn’t get sick.disease, he doesn’t get sick.

Passive ImmunityPassive Immunity

Naturally AcquiredNaturally Acquired– Example is the passing of antibodies Example is the passing of antibodies

from mother to infant in breast milk from mother to infant in breast milk Artificially AcquiredArtificially Acquired

– Example is when a person receives an Example is when a person receives an infusion of antibodies from someone infusion of antibodies from someone else. else.

Active vs. Passive ImmunityActive vs. Passive Immunity

Active immunity is long-lived, and Active immunity is long-lived, and may last for years or even a life time.may last for years or even a life time.

Passive immunity is short lived, and Passive immunity is short lived, and may last only for a few months.may last only for a few months.

NOTE: A vaccination is not the same as receiving an anti-toxin or anti-venom injection. More on that in Micro class.

ALLERGIESALLERGIES

From a hypersensitivity to From a hypersensitivity to substances such as pollen or animal substances such as pollen or animal hair that would not ordinarily cause a hair that would not ordinarily cause a reaction. There are two types of reaction. There are two types of allergic responses:allergic responses:

Immediate Immediate DelayedDelayed

Immediate allergic responseImmediate allergic response

Occurs within seconds of contact with the Occurs within seconds of contact with the thing causing the allergy. thing causing the allergy.

This is the case with anaphylactic allergies, This is the case with anaphylactic allergies, where someone who is allergic to where someone who is allergic to seafood or peanuts can actually die seafood or peanuts can actually die within minutes because the allergic within minutes because the allergic reaction is so severe the throat swells reaction is so severe the throat swells shut and they can’t breathe. shut and they can’t breathe.

They need an injection immediately of They need an injection immediately of epinephrine that will stop the reaction.epinephrine that will stop the reaction.

Delayed allergic responseDelayed allergic response

Delayed allergic response is when the Delayed allergic response is when the body’s first exposure to the body’s first exposure to the substance will not cause a reaction, substance will not cause a reaction, but all exposures afterward will but all exposures afterward will trigger the response. trigger the response.

An example is poison ivy. An example is poison ivy.

You won’t itch the first time you touch You won’t itch the first time you touch it.it.

Common Common allergensallergens

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Chemical mediators of Chemical mediators of allergiesallergies PreformedPreformed

– histaminehistamine - ↑ - ↑ vascular permeability; smooth muscle vascular permeability; smooth muscle contractioncontraction

– proteases proteases – mucous secretion, generation of complement split– mucous secretion, generation of complement split

productsproducts

Newly formedNewly formed (30-60seconds)(30-60seconds)– leukotrienesleukotrienes - ↑ - ↑ vascular permeability; vascular permeability;

contraction of pulmonary smooth musclescontraction of pulmonary smooth muscles

– platelet activating factor – platelet activating factor – platelet aggregation;platelet aggregation;

contraction of pulmonary smooth musclescontraction of pulmonary smooth muscles

– prostaglanin Dprostaglanin D2 2 – vasodilation; contraction of smooth – vasodilation; contraction of smooth

musclesmuscles

– cytokines – cytokines – chemotactic and inflammatorychemotactic and inflammatory7272

Symptoms of allergySymptoms of allergy

dependent upon dependent upon sitesite of allergen of allergen exposureexposure

wheal-and-flare reactionwheal-and-flare reaction– Pruritis (itching), erythemaPruritis (itching), erythema– skinskin

bronchoconstrictionbronchoconstriction mucous secretionmucous secretion vasodilation (shock)vasodilation (shock)

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Localized anaphylaxis Localized anaphylaxis (atopy)(atopy)

reaction limited to the site of reaction limited to the site of allergen exposureallergen exposure

pruritispruritis (itchy) and(itchy) and urticariaurticaria (hives)(hives)

allergic rhinitis (hay fever)allergic rhinitis (hay fever) asthma (atopic asthma)asthma (atopic asthma) atopic dermatitis (eczema)atopic dermatitis (eczema) food allergiesfood allergies

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Allergic asthmaAllergic asthma stimulation of ‘allergy attack’stimulation of ‘allergy attack’

– airborne allergens – pollen, dust, insect partsairborne allergens – pollen, dust, insect parts– blood borne allergens – viral antigensblood borne allergens – viral antigens– degranulation of mast cells due to IgE cross-linkingdegranulation of mast cells due to IgE cross-linking

lower respiratory tractlower respiratory tract symptomssymptoms

– airway edemaairway edema– mucous secretionmucous secretion– inflammationinflammation– = airway obstruction and damage= airway obstruction and damage

asthmatics are hypersensitive to allergensasthmatics are hypersensitive to allergens~~5% of U.S. population5% of U.S. population

symptoms can range from somewhat mild to life-symptoms can range from somewhat mild to life-threatening (<5% severe asthma)threatening (<5% severe asthma)

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AUTOIMMUNE DISEASEAUTOIMMUNE DISEASE

A hereditary problem where the body A hereditary problem where the body thinks its own tissues are foreign thinks its own tissues are foreign bodies, and it constantly tries to kill bodies, and it constantly tries to kill off its own tissues.off its own tissues.