Chapter 17Chapter 17

Genetics of ImmunityGenetics of Immunity

Justin Hoyt, Ashley George, Jenni Bailey-BoatengJustin Hoyt, Ashley George, Jenni Bailey-Boateng, , and Galen Driverand Galen Driver

Protection is based on the ability of the immune system to recognize foreign surfaces, distinguish Protection is based on the ability of the immune system to recognize foreign surfaces, distinguish self from nonselfself from nonself

The immune system carries out a highly coordinated attack on infectious agentsThe immune system carries out a highly coordinated attack on infectious agents

Pathogens are infections that cause disease; pathogenic organisms include bacteria and single Pathogens are infections that cause disease; pathogenic organisms include bacteria and single celled eukaryotescelled eukaryotes

A virus is a single or double strand of RNA or DNA wrapped in a protein coat that are part of the A virus is a single or double strand of RNA or DNA wrapped in a protein coat that are part of the DNA sequence of chromosomesDNA sequence of chromosomes

Many copies of the same protein assemble, even though virus only has a few protein-encoding Many copies of the same protein assemble, even though virus only has a few protein-encoding genesgenes

Autoimmune condition provides resistance by genes to certain infectious diseases, by encoding Autoimmune condition provides resistance by genes to certain infectious diseases, by encoding antibodies and cytokinesantibodies and cytokines

17.1 Pathogens, Genetic Control, HLA17.1 Pathogens, Genetic Control, HLA

17.1 17.1 Pathogens, Genetic Pathogens, Genetic Control, HLAControl, HLAContinued…Continued…

DNA virus reproduce by inserting their DNA into a cell’s host DNADNA virus reproduce by inserting their DNA into a cell’s host DNA

RNA virus is first copied into DNA by reverse transcriptase, that DNA RNA virus is first copied into DNA by reverse transcriptase, that DNA insert’s into the host cell’s chromosomeinsert’s into the host cell’s chromosome

Diverse viruses, such as HIV, have genetic material that mutates at a high Diverse viruses, such as HIV, have genetic material that mutates at a high rate and cannot repair itselfrate and cannot repair itself

Autoimmune condition provides resistance by genes to certain infectious Autoimmune condition provides resistance by genes to certain infectious diseases, by encoding antibodies and cytokinesdiseases, by encoding antibodies and cytokines

All human cells with nuclei have some human leukocyte antigens (HLA), All human cells with nuclei have some human leukocyte antigens (HLA), they encode cell surface antigensthey encode cell surface antigens

HLA proteins link to sugars forming branchlike glycoproteinHLA proteins link to sugars forming branchlike glycoprotein

HLA genes are closely linked on chromosome 6HLA genes are closely linked on chromosome 6

17.1 ABO Blood Groups, Rh Factor17.1 ABO Blood Groups, Rh Factor

Blood types result from self antigen patterns on red blood cellsBlood types result from self antigen patterns on red blood cells

Blood type incompatibility is caused because antibodies attacking unfamiliar Blood type incompatibility is caused because antibodies attacking unfamiliar antigens in a blood type that does not matchantigens in a blood type that does not match

1901 After many failures of blood transfusions, Austrian Karl Landsteiner 1901 After many failures of blood transfusions, Austrian Karl Landsteiner discovered that humans blood had different typesdiscovered that humans blood had different types

He identified three types A, B and O (AB was discovered later)He identified three types A, B and O (AB was discovered later)

Rh Factor further differentiates blood type by a + or –Rh Factor further differentiates blood type by a + or –

1940 he identified the Rh factor along with A. S. Wiener1940 he identified the Rh factor along with A. S. Wiener

The protein Rh factor (Rhesus) was discovered in a rhesus monkey’s a The protein Rh factor (Rhesus) was discovered in a rhesus monkey’s a bloodblood

The average 3% difference between macaque and human genes The average 3% difference between macaque and human genes

The Rh factor can cause a human mother to could react immunologically The Rh factor can cause a human mother to could react immunologically against the factor in her fetus.against the factor in her fetus.

Now a simple test and a vaccine prevent that reaction, mental retardation, Now a simple test and a vaccine prevent that reaction, mental retardation, or even death in about 20,000 U.S. newborns a year.or even death in about 20,000 U.S. newborns a year.

17.2 The Human Immune System17.2 The Human Immune System

"The immune system is a network of vessels called "The immune system is a network of vessels called lymphatics that transport lymph fluid to bean-shaped lymphatics that transport lymph fluid to bean-shaped structures throughout the body called lymph nodes. structures throughout the body called lymph nodes. The spleen and the thymus gland are also part of the The spleen and the thymus gland are also part of the

immune system as well."   immune system as well."  

17.2 The Human Immune System 17.2 The Human Immune System

Physical Barriers and the Innate Immune Physical Barriers and the Innate Immune ResponseResponse

The  immune system uses 3  The  immune system uses 3  classes of proteins  classes of proteins  (the compliment system, coll-(the compliment system, coll-ectins, and cytokines)  to carry out the  ectins, and cytokines)  to carry out the  response which uses  response which uses  an immediate generalized  innate immunity of an immediate generalized  innate immunity of inflammation, followed by a more specific inflammation, followed by a more specific adaptive immunity to attack pathogens, adaptive immunity to attack pathogens, cancer cells, and transplanted cells after its cancer cells, and transplanted cells after its initial physical barrier defense. initial physical barrier defense. 

Unbroken  skin, mucous membranes,  Unbroken  skin, mucous membranes,  cilia, stomach acid,  cilia, stomach acid,  and diarrhea are examples  of physical and diarrhea are examples  of physical barriers that are nonspecific and are always barriers that are nonspecific and are always on defense to keep foreign object out. on defense to keep foreign object out.

17.2 The Human Immune System17.2 The Human Immune System

Physical Barriers and the Innate Immune Physical Barriers and the Innate Immune ResponseResponse

One  class of proteins used  One  class of proteins used  is the complement system, which punctures is the complement system, which punctures bacterial plasma membranes-bursting cells, bacterial plasma membranes-bursting cells, and dismantles viruses using plasma and dismantles viruses using plasma proteins. The next class, collectins, detect proteins. The next class, collectins, detect differences from human cells, group together, differences from human cells, group together, and correspond to the surfaces of different and correspond to the surfaces of different pathogens and even some RNA viruses. The pathogens and even some RNA viruses. The third protein class is cytokines which have third protein class is cytokines which have numerous roles in immunity. Cytokines called numerous roles in immunity. Cytokines called interferons signal other elements of the interferons signal other elements of the immune system of virus-infected cells which immune system of virus-infected cells which are then destroyed to prevent infection from are then destroyed to prevent infection from spreading. Other cytokines in innate immunity spreading. Other cytokines in innate immunity trigger temporary fever which increases body trigger temporary fever which increases body temperature and kills infecting viruses and temperature and kills infecting viruses and bacteria and also boost phagocytes with the bacteria and also boost phagocytes with the warm body temperature; these are called warm body temperature; these are called interleukin. interleukin.

17.2 The Human Immune System17.2 The Human Immune System

Physical Barriers and the Innate Immune ResponsePhysical Barriers and the Innate Immune ResponseInnate immunity means it is always in your body  ready to attack in case pathogens make it past  Innate immunity means it is always in your body  ready to attack in case pathogens make it past  the physical barriers.  Inflammation causes a hostile environment for some pathogens at the site of an injury and the physical barriers.  Inflammation causes a hostile environment for some pathogens at the site of an injury and sends in phagocyte cells, such as white blood cells and macrophages, to attack the unwanted pathogen. Blood is sends in phagocyte cells, such as white blood cells and macrophages, to attack the unwanted pathogen. Blood is rushed to the injury to warm the area which turns it red and swollen. Plasma dilutes toxins and introduces rushed to the injury to warm the area which turns it red and swollen. Plasma dilutes toxins and introduces antimicrobial chemicals to the injury as well. Along with Inflammation, natural killer cells are also part in Innate antimicrobial chemicals to the injury as well. Along with Inflammation, natural killer cells are also part in Innate Immunity and attack virally infected cells and cancer cells.  Immunity and attack virally infected cells and cancer cells. 

17.2 The Human Immune System 17.2 The Human Immune System

The Adaptive Immune ResponseThe Adaptive Immune Response

Adaptive  response is specific  and directed upon stimulation,  and does not respond  Adaptive  response is specific  and directed upon stimulation,  and does not respond 

instantly like innate  immunity. It has three  basic characteristics, it is diverse defeating many instantly like innate  immunity. It has three  basic characteristics, it is diverse defeating many pathogens, it is specific separating good cells and molecules form bad ones, and it remembers; pathogens, it is specific separating good cells and molecules form bad ones, and it remembers; responding quicker to repeat encounters with foreign antigens then the initial attack. Mutations in responding quicker to repeat encounters with foreign antigens then the initial attack. Mutations in viruses are an exception.   viruses are an exception.  

Lymph  fluid transports white  blood cells, called  lymphocytes, and macrophages  that Lymph  fluid transports white  blood cells, called  lymphocytes, and macrophages  that 

capture and destroy  bacteria, viruses, and  cellular debris. B cells and T cells are two major capture and destroy  bacteria, viruses, and  cellular debris. B cells and T cells are two major lymphocytes that carry out adaptive immunity. lymphocytes that carry out adaptive immunity. 

17.2 The Human Immune System17.2 The Human Immune System

The Adaptive Immune ResponseThe Adaptive Immune ResponseB  cells produce antibodies in response to B  cells produce antibodies in response to stimulation by T cells during the hormonal stimulation by T cells during the hormonal immune response. The B cell divides and immune response. The B cell divides and differentiates into one of two types of cells. differentiates into one of two types of cells. One being Plasma cells, which produce One being Plasma cells, which produce antibodies thoroughly into the bloodstream; antibodies thoroughly into the bloodstream; Antibodies are made up of Y-shaped Antibodies are made up of Y-shaped polypeptides with two light and two heavy-polypeptides with two light and two heavy-chains each, and also stimulate chains each, and also stimulate complement. The other cells are Memory complement. The other cells are Memory cells, which are a secondary immune cells, which are a secondary immune response. These respond to foreign response. These respond to foreign antigens faster and stronger should they antigens faster and stronger should they appear again.appear again.   

17.2 The Human Immune System17.2 The Human Immune System

The Adaptive Immune Response The Adaptive Immune Response 

In the cellular immune response T cells In the cellular immune response T cells activate other cells, including B cells to activate other cells, including B cells to manufacture antibodies and cytotoxic T manufacture antibodies and cytotoxic T cells to discharge cytokines. Cytotoxic T cells to discharge cytokines. Cytotoxic T cells fasten themselves to virus-covered cells fasten themselves to virus-covered cells using T cell receptors and destroy cells using T cell receptors and destroy them.  them. 

After  After  differentiating in the bone marrow, B and T differentiating in the bone marrow, B and T cells migrate to  lymph nodes, the spleen,  cells migrate to  lymph nodes, the spleen,  the thymus gland, and circulate in blood andthe thymus gland, and circulate in blood and tissue fluid. tissue fluid.

17.3 Abnormal Immunity17.3 Abnormal ImmunityInherited Immune Deficiencies Inherited Immune Deficiencies An inherited immune deficiency affects innate and An inherited immune deficiency affects innate and

adaptive immunity, there are more than 20 types of adaptive immunity, there are more than 20 types of these deficienciesthese deficiencies

In granulomatous disease the enzyme oxidase is In granulomatous disease the enzyme oxidase is deficient and cannot produce compounds to kill deficient and cannot produce compounds to kill bacteria. This disease is made of four polypeptide bacteria. This disease is made of four polypeptide chains so four genes encode it and there are four chains so four genes encode it and there are four ways to inherit granulomatous disease. This can be ways to inherit granulomatous disease. This can be cured with bone marrow or umbilical cord stem cell cured with bone marrow or umbilical cord stem cell transplant.transplant.

Mutations in genes can impair cellular immunity and Mutations in genes can impair cellular immunity and antibody segments which can lead to bacterial antibody segments which can lead to bacterial infections. Genes that encode T cell receptors can infections. Genes that encode T cell receptors can lead to inherited immune deficiency because the T lead to inherited immune deficiency because the T cells activate the B cells which create antibodiescells activate the B cells which create antibodies

SCID: severe combined immune deficiencies and affect humoral and cellular immunitySCID: severe combined immune deficiencies and affect humoral and cellular immunityHalf of SCID cases are X-linked. Before antibiotics, people with SCID who had some T cells and no B cells Half of SCID cases are X-linked. Before antibiotics, people with SCID who had some T cells and no B cells would most likely die before age 10 from bacterial infections. The lack of both B and T cells would have would most likely die before age 10 from bacterial infections. The lack of both B and T cells would have killed most patients by 18 months. These are treated with gene therapy. killed most patients by 18 months. These are treated with gene therapy. “ “Bubble Boy” David Vetter had a form a SCID that caused him to be born without a thymus gland. He Bubble Boy” David Vetter had a form a SCID that caused him to be born without a thymus gland. He waited for treatment and after an unsuccessful bone marrow transplant he developed severe infection that waited for treatment and after an unsuccessful bone marrow transplant he developed severe infection that his body could not defend. his body could not defend. Inherited immune deficiency can affect people differently. The virus that causes cold sores can lead to Inherited immune deficiency can affect people differently. The virus that causes cold sores can lead to mental retardation, seizures, and death in some cases. Studies showed that this only happened when the mental retardation, seizures, and death in some cases. Studies showed that this only happened when the two parents were related and the mutation was in both copies of the gene. two parents were related and the mutation was in both copies of the gene.

““Bubble Boy” David Vetter was born in Texas in 1971.Bubble Boy” David Vetter was born in Texas in 1971.

17.3 Abnormal Immunity17.3 Abnormal ImmunityAcquired Immune Deficiency SyndromeAcquired Immune Deficiency Syndrome

Commonly known as AIDS, an HIV virus is acquired and begins the shut down the immune system. Commonly known as AIDS, an HIV virus is acquired and begins the shut down the immune system.

First, the virus attached to the surface protein gp120 and then attaches to two coreceptors on the host cell First, the virus attached to the surface protein gp120 and then attaches to two coreceptors on the host cell suface called CD4 and CCR5. Another protein gp40 anchors gp120 into the viral envelope. When the suface called CD4 and CCR5. Another protein gp40 anchors gp120 into the viral envelope. When the corecepotors bond, virus and cell surfaces change so that the virus can enter the cell.corecepotors bond, virus and cell surfaces change so that the virus can enter the cell.

While in the cell reverse transcriptase catalyzes creation of DNA to match the viral RNA and forms a While in the cell reverse transcriptase catalyzes creation of DNA to match the viral RNA and forms a double helix. The viral DNA is transcribed and translated in the chromosome. This caused T cells to die double helix. The viral DNA is transcribed and translated in the chromosome. This caused T cells to die rapidly and allows infection to set in. B cells can’t help because they are not being activated by the dying rapidly and allows infection to set in. B cells can’t help because they are not being activated by the dying T cells to produce the antibodies. T cells to produce the antibodies.

The body can’t keep up with the spread of the virus. While bone marrow produced 1 billion new T and B The body can’t keep up with the spread of the virus. While bone marrow produced 1 billion new T and B cells each day, the HIV particles are budding from infected cells at the rate of 1 million to 1 billion times cells each day, the HIV particles are budding from infected cells at the rate of 1 million to 1 billion times each day.each day.

The number of people living with AIDS is on the rise. This graph shows the The number of people living with AIDS is on the rise. This graph shows the number of people living with HIV/AIDS in 1990 was 8 million and in 2007 is 33 number of people living with HIV/AIDS in 1990 was 8 million and in 2007 is 33 million, 2 million of them children.million, 2 million of them children.

HIV is very diverse and within days of the initial HIV is very diverse and within days of the initial infection drugs used to treat the virus can be resisted.infection drugs used to treat the virus can be resisted.Being HIV positive means that the virus is present but Being HIV positive means that the virus is present but shows no symptoms. It can take 8-11 years for the shows no symptoms. It can take 8-11 years for the HIV virus to become AIDS.HIV virus to become AIDS.67% of people living with HIV/AIDS live in Sub-67% of people living with HIV/AIDS live in Sub-Saharan AfricaSaharan AfricaThere are three drugs that are most commonly used There are three drugs that are most commonly used to treat AIDS:to treat AIDS:

1.1. Reverse transcriptase inhibitor: blocks the cope Reverse transcriptase inhibitor: blocks the cope of viral RNA into DNAof viral RNA into DNA

2.2. Protease inhibitor: Blocks shortening of certain Protease inhibitor: Blocks shortening of certain viral proteinsviral proteins

3.3. Entry inhibitor: Block HIV from entering the cellEntry inhibitor: Block HIV from entering the cell

17.3 Abnormal Immunity17.3 Abnormal ImmunityAutoimmunityAutoimmunity

Autoimmunity is when the body produces autoantibodies which are antibodies which attack the Autoimmunity is when the body produces autoantibodies which are antibodies which attack the bodies own healthy tissues. Autoimmunity affects 5% of the population. These conditions are not bodies own healthy tissues. Autoimmunity affects 5% of the population. These conditions are not Mendelian because several genes and environmental factors can cause them.Mendelian because several genes and environmental factors can cause them.

A single gene mutation can have different effects. Autoimmune polyendocrinopathy syndrome A single gene mutation can have different effects. Autoimmune polyendocrinopathy syndrome type I makes endocrine glands malfunction and can cause fungal infections at age 5, parathyroid type I makes endocrine glands malfunction and can cause fungal infections at age 5, parathyroid gland failure by age 10, and adrenal gland hormone deficiencies by age 15. gland failure by age 10, and adrenal gland hormone deficiencies by age 15.

Auntoimmunity can arise in different ways:Auntoimmunity can arise in different ways:1. A replicating virus in a cell incorporates the cell’s proteins as it’s own which the immune system recognizes as 1. A replicating virus in a cell incorporates the cell’s proteins as it’s own which the immune system recognizes as

bad and begins to attack it’s own human cells that contain that protein. bad and begins to attack it’s own human cells that contain that protein.

2. Thymocytes that should have dies in the thymus escape and attack healthy tissue2. Thymocytes that should have dies in the thymus escape and attack healthy tissue

3. An outside antigen resembles the body’s own antigen and the immune system goes after both3. An outside antigen resembles the body’s own antigen and the immune system goes after both

4. A female may have cells that express the X chromosome if X inactivation is skewed. The surface antigens of 4. A female may have cells that express the X chromosome if X inactivation is skewed. The surface antigens of these cells do not match the others and the immune system will read them as foreign.these cells do not match the others and the immune system will read them as foreign.

Psoriasis is a common autoimmune disorder affecting Psoriasis is a common autoimmune disorder affecting 5.5 million people in the U.S.5.5 million people in the U.S.

Scleroderma may be caused by fetal cells staying in a Scleroderma may be caused by fetal cells staying in a woman’s system years after her child is born. The cells woman’s system years after her child is born. The cells emerge and the immune system develops antibodies. emerge and the immune system develops antibodies. This causes the skin to harden and causes fatigue, This causes the skin to harden and causes fatigue, swollen joints, and stiff fingers, and more severe swollen joints, and stiff fingers, and more severe consequences like hardening of the lungs and blood consequences like hardening of the lungs and blood vessels. vessels.

17.3 Abnormal Immunity17.3 Abnormal ImmunityAllergiesAllergies

An allergy is the immune system fighting off something that isn’t truly a threat. Many allergens are An allergy is the immune system fighting off something that isn’t truly a threat. Many allergens are particles that are small and can enter the lungs. Larger particles like grass pollen only make it to particles that are small and can enter the lungs. Larger particles like grass pollen only make it to the upper respiratory tract and cause hay fever. Smaller particles like cat dander get into the the upper respiratory tract and cause hay fever. Smaller particles like cat dander get into the lungs and can cause asthma. lungs and can cause asthma.

In an allergy attack antibodies bind to mast cells which release histamine and heparin, allergy In an allergy attack antibodies bind to mast cells which release histamine and heparin, allergy mediators. These mediators cause runny nose, inflammation, rashes, fever, and other allergic mediators. These mediators cause runny nose, inflammation, rashes, fever, and other allergic reactions. reactions.

The rise in allergies are linked to environmental factors, however susceptibilities can be inherited. The rise in allergies are linked to environmental factors, however susceptibilities can be inherited.

Allergies today may have been useful immune functions in the past. People with allergies have Allergies today may have been useful immune functions in the past. People with allergies have higher white blood cell counts which is used to fight parasitic infections which have now become higher white blood cell counts which is used to fight parasitic infections which have now become rare. rare.

Some studies suggest that because allergies are more common in developed countries where Some studies suggest that because allergies are more common in developed countries where children grow up with few infections, allergies may be a reaction to the immune system feeling children grow up with few infections, allergies may be a reaction to the immune system feeling underutilized. This theory is called the hygiene hypothesis. underutilized. This theory is called the hygiene hypothesis.

17.4 Altering Immune Function17.4 Altering Immune FunctionVaccinesVaccines

Vaccines are needed to assist in creating an immune response toward fighting infectious Vaccines are needed to assist in creating an immune response toward fighting infectious diseases and conditions. diseases and conditions.

They trick the immune system into acting early. This is a partial form of a pathogen that causes B They trick the immune system into acting early. This is a partial form of a pathogen that causes B cells to produce antibodies. cells to produce antibodies.

When the natural pathogen is entered in the body, a secondary immune response begins. This When the natural pathogen is entered in the body, a secondary immune response begins. This can happen before the infected individual experiences any symptoms.can happen before the infected individual experiences any symptoms.

Vaccines currently prevent many serious diseases. Some of the current preventable diseases [1]:Vaccines currently prevent many serious diseases. Some of the current preventable diseases [1]:

Cervical CancerCervical Cancer

Hepatitis A & BHepatitis A & B

Human Papillomavirus (HPV)Human Papillomavirus (HPV)

MumpsMumps

MonkeypoxMonkeypox

RabiesRabies

ShinglesShingles

Typhoid FeverTyphoid Fever

Yellow FeverYellow Fever

17.4 Altering Immune Function17.4 Altering Immune FunctionMonoclonal Antibodies (MAb)Monoclonal Antibodies (MAb)

MAb technology mass produces a single B cell MAb technology mass produces a single B cell that preserves and amplifies its antibody. MAb that preserves and amplifies its antibody. MAb also resemble natural human antibodiesalso resemble natural human antibodies

This is the process that was used to creating a This is the process that was used to creating a MAb:MAb:

1.1. A mouse was injected with a sheep’s red A mouse was injected with a sheep’s red blood cell. blood cell.

2.2. The next step is to isolate a single B cell The next step is to isolate a single B cell from the mouse’s spleen and infusing it from the mouse’s spleen and infusing it with a cancerous white blood cell. with a cancerous white blood cell.

3.3. This created a fused cell called a This created a fused cell called a hybridoma. hybridoma. Which produced large Which produced large amounts of a single antibody type and amounts of a single antibody type and divided continuously.divided continuously.

17.4 Altering Immune Function17.4 Altering Immune FunctionCytokines Boost Cellular ImmunityCytokines Boost Cellular Immunity

Cytokines are body chemicals that are used into drugs that can treat different conditions. Cytokines are body chemicals that are used into drugs that can treat different conditions.

If they are not taken correctly, cytokines can have serious side effects and can cause If they are not taken correctly, cytokines can have serious side effects and can cause overdose.overdose.

TransplantsTransplantsSuccessful transplantation involves genetics because each inherited differences in cell Successful transplantation involves genetics because each inherited differences in cell surfaces help determine whether a body will accept the tissue and organ from a particular surfaces help determine whether a body will accept the tissue and organ from a particular donor. donor.

The 4 different transplant types are the following:The 4 different transplant types are the following:

1. Autograft - transfers tissue from one part of a person’s body to another1. Autograft - transfers tissue from one part of a person’s body to another

2. Isograft – tissue from an MZ twin2. Isograft – tissue from an MZ twin

3. Allograft – comes from an individual who is not genetically identical to the recipient but is of 3. Allograft – comes from an individual who is not genetically identical to the recipient but is of the same species the same species

4. Xenograft – transplant tissue from one species to a different species4. Xenograft – transplant tissue from one species to a different species

Rejection Reaction-Or AcceptanceRejection Reaction-Or AcceptanceTissue is recognized as nonself by the immune systemTissue is recognized as nonself by the immune system

T cells, antibodies and activated complement destroy the foreign tissueT cells, antibodies and activated complement destroy the foreign tissue

The bigger the difference in the recipient and the donor cells, the more severe the rejection The bigger the difference in the recipient and the donor cells, the more severe the rejection reactionreaction

17.5 Genomic View of Immunity17.5 Genomic View of ImmunityThe Pathogen’s PerspectiveThe Pathogen’s Perspective

Immunity against infectious disease involves the Immunity against infectious disease involves the human genome and the pathogen’s genomehuman genome and the pathogen’s genome

The human genome reveals how the immune system The human genome reveals how the immune system stops infectious disease and the pathogen genome stops infectious disease and the pathogen genome tells us how they make us sicktells us how they make us sick

Crowd DiseaseCrowd DiseaseSince immunity adapts to an environmental stimulus, Since immunity adapts to an environmental stimulus, illnesses, infections, and epidemics start from a illnesses, infections, and epidemics start from a pathogen that has entered a population that hasn’t pathogen that has entered a population that hasn’t ever been exposed to it beforeever been exposed to it before

Most crowd disease go away quickly due to vaccines Most crowd disease go away quickly due to vaccines and treatments and people changing their behaviors to and treatments and people changing their behaviors to avoid contracting the infections. avoid contracting the infections.

BioweaponsBioweaponsBioweapons use pathogens that are either in a natural Bioweapons use pathogens that are either in a natural state or are genetically created.state or are genetically created.

Their main purpose is to kill peopleTheir main purpose is to kill people

ReferencesReferences1. Vaccines and Preventable Diseases. Center for Disease Control and Prevention,1. Vaccines and Preventable Diseases. Center for Disease Control and Prevention,

http://www.cdc.gov/vaccines/vpd-vac/default.htmhttp://www.cdc.gov/vaccines/vpd-vac/default.htm. March 23. March 23, 2009., 2009.

2. Global HIV/AIDS estimates, end of 2007. Alert: Altering HIV and AIDS,2. Global HIV/AIDS estimates, end of 2007. Alert: Altering HIV and AIDS,http://http://www.avert.org/worldstats.htmwww.avert.org/worldstats.htm.. July 6, 2009. July 6, 2009.

3. How long does it take for HIV to cause AIDS? Aids.org,3. How long does it take for HIV to cause AIDS? Aids.org,http://www.aids.org/info/FAQs.html. http://www.aids.org/info/FAQs.html. 2007. 2007.

4. Nobelprize.org 2001 Blood Groups, Blood Typing and Blood Transfusions The discovery of blood 4. Nobelprize.org 2001 Blood Groups, Blood Typing and Blood Transfusions The discovery of blood groups groups <<http: //nobelprize .org/ educational _ games / medicine/ landsteiner/ readmore.htmlhttp: //nobelprize .org/ educational _ games / medicine/ landsteiner/ readmore.html>>

5. Lewis, 2008, Human Genetics Concepts and Applications, McGraw Hill, New York, NY, PP. 327-5. Lewis, 2008, Human Genetics Concepts and Applications, McGraw Hill, New York, NY, PP. 327-332332

6. "6. "Karl Karl LandsteinerLandsteiner." ." The Columbia Encyclopedia, Sixth EditionThe Columbia Encyclopedia, Sixth Edition. 2008. . 2008. Encyclopedia.com.Encyclopedia.com. 12 Jul. 12 Jul. 2009 2009 http://http://www.encyclopedia.comwww.encyclopedia.com

7. Elizabeth Pennisi , 2007, Boom Time for Monkey 7. Elizabeth Pennisi , 2007, Boom Time for Monkey <Researchhttp://www.sciencemag.org/cgi/content/full/316/5822/216><Researchhttp://www.sciencemag.org/cgi/content/full/316/5822/216>