Immunology Teachable Unit

I. Title: Connecting Microbiology to Human Biology

II. Developer: Lisa Lenertz

III. Description: This unit introduces non-science majors to human biology through lessons about innate and adaptive immunity, vaccines, autoimmune diseases, allergies, and current events related to immunology. The overarching goal of the unit is to ignite student interest in immunology topics that are directly related to their lives. Although this unit was designed for non-science majors, the context can be modified to accommodate biology majors. This unit spans five days, but ideally a few more classes should be allowed to cover each topic in detail because immunology is often a difficult subject for students to grasp. Lectures, small group discussions, and a large class debate are used in this teachable unit.

IV. Learning Goals and Outcomes:

Lesson 1 - Introduction to Immunology

Learning Goal Learning OutcomeThe students will understand the major differences between innate and adaptive immunity in terms of resistance or protection against microbial pathogens.

The students will be able to describe the major differences between innate and adaptive immunity.

Lesson 2 - Innate Immunity

Learning Goal Learning OutcomesThe students will know the major components of the innate immune response.

The students will be able to describe the major cell players in the innate immune response.

The students will be able to list major innate immune response processes and describe their purposes.

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Lesson 3 - Adaptive Immunity

Learning Goals Learning OutcomesThe students will understand the relationship between antigens and antibodies.

The students will understand how the various immune cells of the adaptive immune response function to combat infections.

The students will understand how antibodies work to protect the body against invading pathogenic microbes.

The students will be able to list the major immune cells and describe how they work with other cells.

The students will be able to describe the basic functions of antibodies and how antibodies are generated following an infection.

The students will be able to describe how the adaptive immune response has memory.

Lesson 4 - Autoimmune Diseases and Allergies

Learning Goals Learning OutcomesThe students will understand how allergen particles are presented to the immune system.

The students will understand how hypersensitivities develop.

The students will understand the basic mechanisms by which autoimmune diseases cause harm to the body.

The students will be able to articulate how allergen particles induce allergic reactions.

The students will research an autoimmune disease of interest and be able to describe what is and what is not known about its causes, the mechanisms of how the disease causes harm, and current treatments.

Lesson 5 - Vaccines

Learning Goals Learning OutcomesThe students will understand the basic mechanism by which vaccines create immunological "memory".

The students will understand why vaccines do not cause disease.

The students will articulate how vaccinations activate the adaptive immune response and why our bodies are protected against assaults from the pathogen the vaccine was developed for.

The students will be able to explain why vaccines do not cause disease.

The students will defend or refute Texas Governor Rick Perry's attempt to mandate the HPV vaccine.

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V. Scientific Teaching Themes:

Scientific Teaching

Each lesson addresses a complex and difficult subject for students. The overall goal of this unit is for non-science majors to have a better understanding of how the human body responds to infections and to have a basic understanding of how the immune system can function improperly to cause autoimmune diseases and allergic reactions. Mini lectures, group activities, homework assignments, and a class debate are used in this unit to help address several misconceptions that students have about immunity, allergies, autoimmune diseases and vaccines.

Active Learning

The active learning activities include question and answer sessions during the beginning of each class and a whole class debate about mandatory vaccinations. In addition, class discussions are incorporated into the lectures. More details about the active learning activities are provided in the instructor materials.

Assessment

Student learning is assessed through several mechanisms including participation in group discussions, a group debate, a worksheet, short written assignments, and a research paper. I look over the short written assignments after class and address any common problems in the first fifteen minutes of the next class. I also make comments on each assignment and give those to the students during the following class in order for them to assess what they do and do not understand before we move onto new topics.

Diversity

Once the course begins, we ask students to contact us if they have special needs such as having a learning disability, and we determine how to accommodate those students. To address racial, ethnic, regional, and political diversity, I use examples from different population groups whenever possible. For example, when discussing the smallpox vaccine, I describe how different nations throughout history have dealt with smallpox. As another example, the HPV vaccine debate is about Texas Governor Rick Perry's attempt to mandate the vaccine for girls entering the sixth grade. This addresses regional and political ideology diversity.

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VI. Teaching Plan:

Lesson 1 - Introduction to Immunology Timeline

Time Topic Activity Goals0-8 Introduction of

immunology fieldMini-lecture Familiarize students with the

history of immunology9-13 Pathogens we are

immunized againstSmall group activity Students think about what

they have been vaccinated against.

14-18 Innate vs. adaptive immunity

Mini-lecture Students are introduced to the broad, major differences between innate and adaptive immunity.

19-26 Cells of the immune system

Mini-lecture Students are introduced to the players in the immune system.

27-33 Overview of innate immunity

Mini-lecture Students are familiarized with the basics of innate immunity.

35-42 Overview of adaptive immunity

Mini-lecture Students are familiarized with the basics of adaptive immunity.

43-48 How adaptive immunity establishes memory

Mini-lecture Students think about the basics of how vaccines protect us from invading pathogens.

49-50 Reflection Short written assignment

Students articulate one topic or question that was confusing.

Homework assigned: Read chapters in immunology textbook. Our students used Ken Todar's online Bacteriology Textbook.

Lesson 2 - Innate Immunity

Timeline

Time Topic Activity Goals0-15 Review Discussion of

responses to the short written assignment

Clarify what students were confused about in the previous class.

16-22 Overview of innate immunity components

Mini-lecture Students think about our various defenses against invading pathogens.

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23-30 Innate immunity components in detail

Mini-lecture Students are familiarized with the components of the innate immune system.

31-37 Inflammation Mini-lecture, discussion about inflammatory diseases such as asthma

Students gain an understanding of the fundamentals of inflammation and reflect on any inflammatory diseases they may suffer from.

38-44 Phagocytosis Mini-lecture Students are introduced to the process of phagocytosis and its importance.

45-48 Fever Mini-lecture Students acknowledge why getting a fever can be beneficial.

49-50 Reflection Short written assignment

Students articulate one topic or question that was confusing.

Homework assigned: Read chapters in immunology textbook and do worksheet.

Lesson 3 - Adaptive Immunity

Timeline

Time Topic Activity Goals0-15 Review Discussion of

responses to the short written assignment

Clarify what students were confused about in the previous class.

16-22 Introduction to adaptive immunity

Mini lecture Students are familiarized with the basics of adaptive immunity.

23-28 Antigens & blood typing

Whole class discussion about ABO blood typing

Students are introduced to the concept of antigens and immunity.

29-37 Antibodies Mini lecture Students are introduced to the concept of antibodies.

38-44 Primary and secondary responses

Mini lecture Students gain an understanding of how vaccines work to protect us from infections.

45-48 Cell-mediated immunity

Mini lecture Students are familiarized with the major functions of T cells.

49-50 Reflection Short written assignment

Students articulate one topic or question that was

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confusing.

Homework assigned: Read chapters in immunology textbook and start research paper.

Lesson 4 - Allergies and Autoimmune Diseases

Timeline

Time Topic Activity Goals0-15 Review Discussion of

responses to the short written assignments

Clarify what students were confused about in the previous class.

16-19 Definitions of allergies and autoimmune diseases

Mini lecture Students become familiarized with the concept that the immune system can function improperly

20-26 Immediate and delayed hypersensitivities

Mini lecture Students are introduced to the concept of hypersensitivities and examples between immediate and delayed.

27-31 Basics of autoimmune diseases

Mini lecture Students are familiarized with the basics of a few autoimmune diseases.

32-48 Hypotheses for why we seem to have more allergies

Whole class discussion

Students realize that there is no clear explanation for why we seem to develop more allergies.

49-50 Reflection Short written assignment

Students articulate one topic or question that was confusing.

Homework assigned: Short reflection paper about mandatory HPV vaccinationsHomework due: worksheet

Lesson 5 - Vaccines

Timeline

Time Topic Activity Goals0-15 Review Discussion of

responses to the short written assignments

Clarify what students were confused about in the previous class.

16-20 Vaccines Mini lecture Students review the mechanisms by which

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vaccines establish "memory"21-50 Mandatory HPV

vaccinationsWhole class debate Students defend their personal

position about mandatory HPV vaccinations.

Homework due the following week: research paper, short reflection paper about mandatory HPV vaccinations

VII. Instructor Materials:

The following is the student handout for the unit with notes that an instructor can use during a chalk talk. Notes that are in addition to what is in the handout are in blue; short active learning activities are in red. This handout can be tailored to different levels of difficulty. I found that is was challenging to cover all of the material in five days, therefore either one or two more days should be allotted for this unit or some material should be cut. For a non-science major course, I think it is important to allow enough time to discuss allergies and autoimmune diseases in detail, which are topics that are important to our daily lives and are interesting to students. Additionally, I routinely discussed my own research throughout the chalk talks in order for the students to gain a better understanding of the relevance of the particular topic and to increase student interest.

Immunology: The study of our responses to invading microbes that leads to resistance and protection.

Complicated field; origins attributed to Edward Jenner - vaccinated against smallpox using cowpox

Immune system protects us from….. Ask students to give examples of the following….

1) bacteria: E. coli, Staph, Strep, Salmonella, Tetanus, etc

2) viruses: Rhinovirus-common cold, Herpes, influenza, etc

3) fungi: Aspergillis

4) parasites: eukaryotes: tapeworms, flukes, Giardia, etc

Have the students pair up and list some bacteria and viruses we are immunized against.Bacteria: tetanus, whooping cough, diphtheria, meningitis

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Viruses: polio, MMR, hepatitis, HPV, shingles, yellow fever Innate Immunity Adaptive Immunity

1st line of defense 2nd line of defense upon initial exposure

nonspecific specific

responds almost immediately takes time to react

does not have a "memory" has a "memory"

Multiple cell types comprise the immune system. Some are components of the innate response, some are components of the adaptive response, and may bridge the two responses.

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B cells: bone marrow; antibody-mediated immunityT cells: thymus; cell-mediated immunity; also have memory cells

Immune system cells - Overview

B cells: develop into plasma cells that produce antibodies, proteins that recognize and disable foreign substances called antigens establish immunological memory

Draw a model of an antibody-antigen complex.

Memory cells: longer lived, become plasma cells when activated. Plasma cells have large ER (protein producing machines) & are short lived.

T cells: recognize and respond to antigens expressed on body cells known as antigen- presenting cells

establish immunological memory

T helper: activate everyone, secrete interferon gamma, complex w/ dendritic cells (they activate each other, T helper cells start dividing, and then they activate

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B cells, macrophages, neutrophils, etc)

Natural killer cells: "police" the body lyse virus-infected cells are relatively non-specific in what cells they kill

Scan for cells not expressing MHCI, which is suppressed in viral infected & tumor cells

Neutrophils: short-lived cells that phagocytose, or engulf, invading microbes contain many bactericides

Phagocytosis: discussed in detail next lecture; critical component of the innate immune response

Eosinophils: release cytotoxic proteins that damage parasitic worms releases inflammatory mediators, mediating tissue damage in asthmatic

individuals

Highly granulated cells that have not been extensively studied. "Primed" upon allergen challenge. People with allergies have more eosinophils.

Basophils: have poorly understood functions aid in combating parasitic worm infections may be involved in inflammation

We don't have many of them.

Mast cells: aid in combating parasitic worm infections important in inflammation

Found in connective tissue. Many are in the skin, intestinal wall, lungs, mouth, & nose and they interact with the outside environment & are in the vicinity of blood cells. They signal injury & degranulate to release histamine & heparin (blood flows to the area) Dendritic cells: present processed antigenic fragments to T cells

Antigen presenting cell

Macrophages: phagocytose foreign microbes & dead cells present processed antigenic fragments to T cells

long-lived cells release factors that amplify inflammation

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Antigen presenting cellNot as activated in newborns & the elderly

Innate Immunity - Overview

We are exposed or infected by various microbes. Despite this, infectious disease is quite rare because the innate immune system usually takes care of any problems.

primary defense mechanism

upon an initial exposure to a pathogen, is the first to act

defenses are always present

New cells do not need to be madeAnatomical defenses (skin, mucous membranes), macrophages, etc

defenses respond immediately upon infection reacts similarly to a variety of organisms

Undergoes similar processes no matter what the insult is

Adaptive Immunity - Overview

clears most infections that the innate immune response cannot take care of

reacts to a particular pathogen

Specific antibodies react to specific pathogens

when trigged by first exposure to a pathogen, it takes time to develop

Memory B and T cells and antibody-producing plasma cells must fully develop

can "remember" pathogens that previously invaded the body and can react more quickly the second time the body is invaded by the same pathogen (Active immunity)

the cells are already there to react

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2 types of adaptive immunity

1) Antibody-mediated immunity

Antibodies circulate freely in the blood and lymph. Antibodies are produced by plasma B cells and utilize several mechanisms to help eliminate pathogens.

2) Cell-mediated immunity

T cells recognize foreign particles (antigens) and undergo several events to help eliminate the threat.

Only active immunity establishes "memory"

Active immunity: infection

vaccine

Killed or inactivated organisms or purified products derived from the organismFirst known form of vaccinations was variolation of smallpox (used actual smallpox though; current smallpox vaccine is live virus- vaccinia)Edward Jenner

Passive immunity: certain types of antibodies pass from mother to fetus via the

placenta or to infant via milk

short-lived

injection of immune serum (antivenom, antitoxin)

doesn't establish memory

Innate Immunity

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Components of Innate Immunity:

Natural Resistance: species resistance, individual resistance (age, sex, therapy against other diseases), temp, pH

Normal Flora: resident flora prevent colonization of invaders

Anatomical Defenses: skin, mucous membranes, cilia

Tissue Bactericides: lactoferrin, lysozyme, complement

Inflammation: focuses host defenses, maybe most important component

Phagocytosis: neutrophils and macrophages, cells eat pathogens

Fever: systemic response (whole body response)

Natural Resistance: Some pathogens cannot colonize and survive in certain host environments.

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Dogs, not humans get distemper.Some species can evolve and infect hosts they didn't infect before (avian flu).Sex: orchitis- inflammation in testicles; mastitis- infection that occurs after breast feeding.

Normal Flora: Normal flora prevent the colonization of foreign microorganisms.

Competition for binding sites.

Proteins called bacteriocins and a variety of metabolites produced by indigenous species kill or inhibit other bacteria.

Anatomical Defenses: Protective surfaces that keep pathogens out.

Skin

Is compromised by cuts, burns and bites

Mucous membranes/epithelium

Respiratory tractMucus flow and epithelial cilia keeps pathogens from attaching to

epithelia Digestive tract

Peristalsis keeps pathogens from attaching

Genitourinary tract

Eyes

Epithelial Tissues show point power slidesAsk the students what it is about epithelia that keep pathogens out.

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Ciliated epithelium

cilia

Tissue Bactericides: Molecules that have anti-microbial properties.

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Lysozyme - lyses bacteria

Lactoferrin - inhibits bacterial growth by withholding needed iron

Interleukin-1 & tumor necrosis factor alpha - cause fever

Complement - promotes lysis of bacteria, participates in inflammation & opsonization (coating of foreign particles to make

them "tasty" to phagocytic cells)

Inflammation: A tissue reaction to injury or infection. Symptoms are redness, swelling, heat, & pain.

Essential to combating infections

redness: due to increased blood flow to injured area

swelling: due to increased extravascular fluid & phagocyte infiltration to affected area

heat: due to increased blood flow & action of pyrogens (fever-inducing agents)

pain: caused by local tissue destruction & irritation of sensory nerves

Antimicrobial effects of inflammation:

1) increases the blood supply & temperature in affected area, which promotes maximal metabolic activity of immune response cells

2) delivers inflammatory exudate to affected area, which contains phagocytes, lymphocytes, lysozyme, antibodies & other factors

Inflammation is normally a good thing, but excessive inflammation can cause harm to the body.

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asthma Ask the students if they have asthma and start a brief discussion.Common chronic diseaseIncreasing problem in the developed worldExcessive inflammation in the airwayEpisodes can be triggered by common cold, exercise, allergens

arthritisInflammation in the joints

Crohn's diseaseClassified as an inflammatory bowel disease; not pleasantGenetic linkAbdominal pain, diarrhea, increased risk of cancer in inflamed areas

ChostochondritisInflammation of cartilage that connects a rib to the breastbonePain may mimic the pain of having a heart attackInduced by excessive exercise, injury, etcPainful when breathing

Phagocytosis: Engulfment & destruction of pathogensPhagocytic cells:

1) neutrophils - contain granules; are short-lived cells

2) macrophages - local & blood-borne cells; longer-lived cells

Show power point slide

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Steps of phagocytosis: shower power point slide

1) phagocytic cells wrap their cell membranes around pathogen to form a phagosome

2) phagosome becomes acidified

3) phagosome fuses with lysosomes (contain digestive enzymes) to form a phagolysosome

4) targets killed within phagolysosome

Fever: Increase in body temperatureAsk the students what can be detrimental about high fevers.

systemic response

sequesters iron & zinc which are needed for bacteria to multiply

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increases the metabolic rate of cells to speed up repair

Adaptive Immunity: Stalks and eliminates nearly every infection that cannot be cleared by the innate response.

Unlike the innate immune response it must be primed by an initial exposure to the foreign substance (antigen).

Vaccination, chickenpox, etc

4 important aspects:1) It is specific - recognizes specific pathogens

Recognizes specific antigens on the pathogens - proteins exposed on the surface of pathogens

2) It is systemic - not restricted to initial infection site

Whole body response

3) It has "memory" - after an initial exposure, it recognizes & mounts an even stronger attack

antibodies are produced upon initial exposure - able to react the 2nd time

4) It is tolerant - it generally does not react to "self" proteins

Doesn't attack proteins on the surface of body cells

2 types:

1) antibody-mediated immunity

2) cell-mediated immunity

Complete Antigens:

substances that mobilize the immune response; what antibodies recognize

molecules found on pathogens

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not normally present in the body

are nonself

Self Antigens:

not foreign to us

foreign to others (transplant rejection, receiving the wrong blood type)

ABO blood activity: List each blood type with what antigens are presented and what antibodies are produced. Ask the students what blood type they have. Ask the students what blood type is the universal donor and what is the universal acceptor.

Antibody-mediated immunity:

Upon antigenic stimulus, B lymphocytes become transformed into antibody- secreting plasma cells or long-lived memory cells.

Each antibody (also known as immunoglobulin) recognizes a specific antigen.

Antibody-antigen complexes

Explain constant & variable regions.

Discuss how we produce antibodies in the lab.

Antibodies have multiple functions.

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Opsonization: coat foreign particles & make them susceptible to phagocytosis

Makes them "tasty" for phagocytic cells

Steric hindrance: block microbe attachment to host cells

Microbes can't adhere to epithelium & invade

Toxin neutralization: block the interaction of bacterial toxins with their targets

Agglutination or precipitation: combine with the surfaces of microbes, causing them to agglutinate or precipitate

and making them susceptible to phagocytosis

Activation of complement: the complement cascade has 4 major effectsComplex system

1) induction of inflammation

2) attract phagocytes to infection site

3) opsonization of microbes

4) lysis of bacteria or viral-infected cells

There are different classes of antibodies: IgG, IgM, IgA, IgE, IgD

IgD: bound to B cellsIgE: anaphylaxis, troublemaker

IgG: predominant immunoglobulin in the body(Body glad) can diffuse into extravascular spaces

crosses the placental barrier, providing passive immunity to fetus for 6 months of life

basis of passive immunity provided by most natural antiserums

IgM: first immunoglobulin to be synthesized by infants(body mad) made weeks to months after birth

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first immunoglobulin to appear in the blood stream during an infection

secreted onto mucosal surfaces

IgA: participates in local defense of mucosal surfaces (ears, eyes, nose, throat)

antibodies secreted onto mucosal surfaces

Highest Ig found in breast milk: shielded by secretory components with protects it from degradation in digestive tract

When the body is infected with a particular pathogen the second time (secondary response), memory B cells are able to quickly recognize the pathogen and stimulate a faster immunological response than after the first encounter with that pathogen (primary response).

Primary and secondary immunological responses

Cell-mediated immunity:

More complicated than antibody-mediated immunity

2 main cell types involved:

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1) CD4 cells: are primarily helper T cells

What HIV attacks, along with macrophages & dendritic cells

2) CD8 cells: cytotoxic T cells

MHC class I: most cells, normally display self antigens; recognized by CD8+MHC class II: mature B cells, some T cells, APCs; recognized by CD4+

T helper cells stimulate B cells & T cytotoxic cells (link between cell-mediated & antibody-mediated immunity)

Helper T cells: bind to antigens present on an antigen presenting cells

stimulate cytotoxic T cells and B cells to help fight the invader

Cytotoxic T cells: also called killer T cellsKill HIV-infected helper T cells

lyse infected cells by releasing the contents of its granules

activated by antigens present on any cell, not just antigen presenting cells

activity is enhanced by helper T cells

involved in rejection of foreign tissue grafts

Regulatory T cells: suppress immune responses at sites of inflammation1) direct killing of cytotoxic cells2) inhibition of cytokine production3) secrete anti-inflammatory factors

Vaccines

4 main types of vaccines:

1) killed microbes

2) live, attenuated virus

3) toxoids - inactivated toxic compounds from the microbes

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4) proteins - Hepatitis B, HPV

- In the case of smallpox, vaccination using the live, related viruses, cowpox and vaccinia virus, provided protection against smallpox.

- DNA-based viruses are under investigation: easier to transport and store

Ask the students how the body responds to vaccines. Discuss B cells and primary vs. secondary responses.

List of vaccine-preventable diseases (CDC)AnthraxCervical cancerDiphtheriaHepatitis AHepatitis BHaemophilus influenzae type bInfluenzaJapanese EncephalitisLyme diseaseMeaslesMeningococcalMonkeypoxMumpsWhooping coughPneumococcalPolioRabiesRotavirusRubella (German measles)Shingles (Herpes Zoster)SmallpoxTetanus (Lockjaw)TuberculosisTyphoid FeverChickenpox (Varicella)Yellow Fever

Allergies and Autoimmune Diseases

Allergies and autoimmune diseases develop when the immune system has gone haywire.

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Allergies: The immune system attacks something that is not normally harmful to the body.

exaggerated response to presented antigens

Autoimmune disease: The body perceives itself as "nonself" and mounts an attack.

body is no longer tolerant to "self"

Immediate hypersensitivity (Type I hypersensitivity)

can happen quickly (usually more severe)

can also be a delayed response

Anaphylactic shock is a life threatening, severe whole body response to an allergen

Treatment options:

1) Benadryl

2) corticosteroids to decrease inflammation

Anaphylaxis: most common type IFirst encounter: - APCs present allergen to T cells

- IL-4 secretion by T helper cells - B cells secrete IgE that attach to mast cells & basophilsSecond encounter: - allergen binds to IgE & causes degranulation Atopy: - don't need to be sensitized to allergen

- react immediately

Delayed hypersensitivity (Type IV hypersensitivity):

appear within 1-3 days

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mediated by cells

allergic contact dermatitis: poison ivy, heavy metals, cosmetics; can be passed through transfusions of T cells; TB skin test

Discuss hygiene hypothesis: Th1 vs Th2 (decreased number of childhood diseases, less Th1, more Th2)

VIII. Student Materials:

Immunology Handout

Immunology: The study of our responses to invading microbes that leads to resistance and protection.

Immune system protects us from…..

1) bacteria

2) viruses

3) fungi

4) parasites

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Innate Immunity Adaptive Immunity

1st line of defense 2nd line of defense upon initial exposure

nonspecific specific

responds almost immediately takes time to react

does not have a "memory" has a "memory"

Multiple cell types comprise the immune system. Some are components of the innate response, some are components of the adaptive response, and may bridge the two responses.

27

Immune system cells - Overview

B cells: develop into plasma cells that produce antibodies, proteins that recognize and disable foreign substances called antigens establish immunological memory

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T cells: recognize and respond to antigens expressed on body cells known as antigen- presenting cells

establish immunological memory

Natural killer cells: "police" the body lyse virus-infected cells are relatively non-specific in what cells they kill

Neutrophils: short-lived cells that phagocytose, or engulf, invading microbes contain many bactericides

Eosinophils: release cytotoxic proteins that damage parasitic worms releases inflammatory mediators, mediating tissue damage in asthmatic

individuals

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Basophils: have poorly understood functions aid in combating parasitic worm infections may be involved in inflammation

Mast cells: aid in combating parasitic worm infections important in inflammation

Dendritic cells: present processed antigenic fragments to T cells

Macrophages: phagocytose foreign microbes present processed antigenic fragments to T cells

long-lived cells release factors that amplify inflammation

Innate Immunity - Overview

We are exposed or infected by various microbes. Despite this, infectious disease is quite rare because the innate immune system usually takes care of any problems.

primary defense mechanism

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defenses are always present

defenses respond immediately upon infection

reacts similarly to a variety of organisms

Adaptive Immunity - Overview

clears most infections that the innate immune response cannot take care of

reacts to a particular pathogen

when trigged by first exposure to a pathogen, it takes time to develop

can "remember" pathogens that previously invaded the body and can react more quickly the second time the body is invaded by the same pathogen (Active immunity)2 types of adaptive immunity

1) Antibody-mediated immunity

Antibodies circulate freely in the blood and lymph. Antibodies are produced by plasma B cells and utilize several mechanisms to help eliminate pathogens.

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2) Cell-mediated immunity

T cells recognize foreign particles (antigens) and undergo several events to help eliminate the threat.

Only active immunity establishes "memory"

Active immunity: infection

vaccine

Passive immunity: certain types of antibodies pass from mother to fetus via the

placenta or to infant via milk

short-lived

injection of immune serum (antivenom, antitoxin)

Innate Immunity

Components of Innate Immunity:

Natural Resistance

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Normal Flora

Anatomical Defenses

Tissue Bactericides

Inflammation

Phagocytosis

Fever

Natural Resistance: Some pathogens cannot colonize and survive in certain host environments.

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Normal Flora: Normal flora prevent the colonization of foreign microorganisms.

Anatomical Defenses: Protective surfaces that keep pathogens out.

Skin

Mucous membranes/epithelium

Respiratory tract

Digestive tract

Genitourinary tract

Eyes

Epithelial Tissues

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Ciliated epithelium

cilia

Tissue Bactericides: Molecules that have anti-microbial properties.

35

Lysozyme - lyses bacteria

Lactoferrin - inhibits bacterial growth by withholding needed iron

Interleukin-1 & tumor necrosis factor alpha - cause fever

Complement - promotes lysis of bacteria, participates in inflammation & opsonization (coating of foreign particles to make

them "tasty" to phagocytic cells)

Inflammation: A tissue reaction to injury or infection. Symptoms are redness, swelling, heat, & pain.

redness: due to increased blood flow to injured area

swelling: due to increased extravascular fluid & phagocyte infiltration to affected area

heat: due to increased blood flow & action of pyrogens (fever-inducing agents)

pain: caused by local tissue destruction & irritation of sensory nerves

Antimicrobial effects of inflammation:

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1) increases the blood supply & temperature in affected area, which promotes maximal metabolic activity of immune response cells

2) delivers inflammatory exudate to affected area, which contains phagocytes, lymphocytes, lysozyme, antibodies & other factors

Inflammation is normally a good thing, but excessive inflammation can cause harm to the body.

asthma

arthritis

Crohn's disease

Chostochondritis

Phagocytosis: Engulfment & destruction of pathogens

Phagocytic cells:

1) neutrophils - contain granules; are short-lived cells

2) macrophages - local & blood-borne cells; longer-lived cells

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Steps of phagocytosis:

1) phagocytic cells wrap their cell membranes around pathogen to form a phagosome

2) phagosome becomes acidified

3) phagosome fuses with lysosomes (contain digestive enzymes) to form a phagolysosome

4) targets killed within phagolysosome

38

Fever: Increase in body temperature

systemic response

sequesters iron & zinc which are needed to bacteria to multiply

increases the metabolic rate of cells to speed up repair

39

Adaptive Immunity: Stalks and eliminates nearly every infection that cannot be cleared by the innate response.

Unlike the innate immune response it must be primed by an initial exposure to the foreign substance (antigen).

4 important aspects:

1) It is specific - recognizes specific pathogens

2) It is systemic - not restricted to initial infection site

3) It has "memory" - after an initial exposure, it recognizes & mounts an even stronger attack

4) It is tolerant - it generally does not react to "self" proteins

2 types:

1) antibody-mediated immunity

2) cell-mediated immunity

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Complete Antigens:

substances that mobilize the immune response; what antibodies recognize

molecules found on pathogens

not normally present in the body

are nonself

Self Antigens:

not foreign to us

foreign to others (transplant rejection, receiving the wrong blood type)

Antibody-mediated immunity:

Upon antigenic stimulus, B lymphocytes become transformed into antibody- secreting plasma cells or long-lived memory cells.

Each antibody (also known as immunoglobulin) recognizes a specific antigen.

41

Antibody-antigen complexes

Antibodies have multiple functions.

Opsonization: coat foreign particles & make them susceptible to phagocytosis

Steric hindrance: block microbe attachment to host cells

Toxin neutralization: block the interaction of bacterial toxins with their targets

Agglutination or precipitation: combine with the surfaces of microbes, causing them to agglutinate or precipitate

and making them susceptible to phagocytosis

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Activation of complement: the complement cascade has 4 major effects

1) induction of inflammation

2) attract phagocytes to infection site

3) opsonization of microbes

4) lysis of bacteria or viral-infected cells

There are different classes of antibodies: IgG, IgM, IgA, IgE, IgD

IgG: predominant immunoglobulin in the body

can diffuse into extravascular spaces

crosses the placental barrier, providing passive immunity to fetus for 6 months of life

basis of passive immunity provided by most natural antiserums

IgM: first immunoglobulin to be synthesized by infants

first immunoglobulin to appear in the blood stream during an infection

secreted onto mucosal surfaces

IgA: participates in local defense of mucosal surfaces

antibodies secreted onto mucosal surfaces

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When the body is infected with a particular pathogen the second time (secondary response), memory B cells are able to quickly recognize the pathogen and stimulate a faster immunological response than after the first encounter with that pathogen (primary response).

Primary and secondary immunological responses

Cell-mediated immunity:

More complicated than antibody-mediated immunity

2 main cell types involved:

1) CD4 cells: are primarily helper T cells

2) CD8 cells: cytotoxic T cells

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Helper T cells: bind to antigens present on an antigen presenting cells

stimulate cytotoxic T cells and B cells to help fight the invader

Cytotoxic T cells: also called killer T cells

lyse infected cells by releasing the contents of its granules

activated by antigens present on any cell, not just antigen presenting cells

activity is enhanced by helper T cells

involved in rejection of foreign tissue grafts

Vaccines

4 main types of vaccines:

1) killed microbes

2) live, attenuated virus

3) toxoids - inactivated toxic compounds from the microbes

4) proteins - Hepatitis B, HPV

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- In the case of smallpox, vaccination using the live, related viruses, cowpox and vaccinia virus, provided protection against smallpox.

- DNA-based viruses are under investigation: easier to transport and store

List of vaccine-preventable diseases (CDC)AnthraxCervical cancerDiphtheriaHepatitis AHepatitis BHaemophilus influenzae type bInfluenzaJapanese EncephalitisLyme diseaseMeaslesMeningococcalMonkeypoxMumpsWhooping coughPneumococcalPolioRabiesRotavirusRubella (German measles)Shingles (Herpes Zoster)SmallpoxTetanus (Lockjaw)TuberculosisTyphoid FeverChickenpox (Varicella)Yellow Fever

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Allergies and Autoimmune Diseases

Allergies and autoimmune diseases develop when the immune system has gone haywire.

Allergies: The immune system attacks something that is not normally harmful to the body.

exaggerated response to presented antigens

Autoimmune disease: The body perceives itself as "nonself" and mounts an attack.

body is no longer tolerant to "self"

Immediate hypersensitivity (Type I hypersensitivity)"

can happen quickly (usually more severe)

can also be a delayed response

Anaphylactic shock is a life threatening, severe whole body response to an allergen

Treatment options:

1) Benadryl

2) corticosteroids to decrease inflammation

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Delayed hypersensitivity (Type IV hypersensitivity):

appear within 1-3 days

mediated by cells

allergic contact dermatitis:

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Immunology Worksheet

1. Name two antigen presenting cells.

2. How do antigen presenting cells help combat infection?

3. Name three cells that are involved in combating parasitic worm infections.

4. Name two cells that respond immediately to an initial infection and describe their roles in fighting invading pathogens.

5. Define inflammation and list one cell that amplifies the process.

6. Name one cell that kills virus-infected cells.

7. What cells establish immunological memory?

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8. Which of the following statements about inflammation is correct? a) Inflammation is a component of the adaptive immune response. b) Excessive inflammation can harm the body. c) Pain, swelling, and redness are hallmarks of inflammation. d) b and c are correct e) none of the above

9. Which of the following statements about epithelium is correct? a) Epithelial tissues are only found on the outside of our bodies and in the digestive tract. b) The tight junctions between epithelial cells help keep pathogens from invading nearby tissues. c) Some epithelial cells contain cilia. d) b and c are correct e) all of the above

10. Which of the following events establish immunological "memory"? a) infections and vaccination b) vaccination and breast feeding c) breast feeding and administering antivenom d) 2 or more of the above e) none of the above

11. Which is the predominant immunoglobulin in the body? a) IgA b) IgD c) IgE d) IgG e) IgM

12. Which blood type are you? (If you don't know, assume you're A for the sake of this quiz). People with what blood type(s) may receive a transfusion from you? What blood type(s) may you receive?

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13. Define the terms antibody and antigen.

14. Explain why our immune system can respond faster the second time we encounter a particular pathogen.

15. What are the functions of helper T cells, cytotoxic T cells and regulatory T cells?

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Autoimmune Disease/Allergy Paper

The immune system is essential in protecting us from pathogens, but when immune responses are not properly regulated, autoimmune diseases and allergies may develop. Write a 3 to 4 page double-spaced paper about one of the following and include references (maximum of six references). Wikipedia is not an acceptable reference but can be used as a starting point to find primary articles. The Mayo Clinic and WebMD have useful information. When citing internet sources, list the web address and the date you went to that website.

Lupus: Lupus is a complicated autoimmune disease where the body makes antibodies against DNA and nuclear proteins. This disease can affect multiple organs including the skin, kidneys and heart.

Rheumatoid arthritis: Rheumatoid arthritis is a chronic painful inflammatory disease where cartilage at the joints is attacked by immune cells.

Multiple sclerosis: Multiple sclerosis is an autoimmune disease where the central nervous system is attacked, specifically the protein myelin.

Asthma: Asthma is a chronic disorder and it is thought is has an increased prevalence in the United States. Inflammation in the lungs leads to airflow obstruction.

Celiac disease: Celiac disease in an autoimmune disorder of the small intestine. The immune system reacts with the protein gluten which is found in wheat products.

Poison oak: Contact with poison oak can result in an annoying allergic reaction that affects the skin.

Drug allergy (including penicillin): Commonly prescribed drugs can cause allergic reactions, particularly antibiotics.

If you would like to write about a different disease/allergy talk to me and I will determine whether I may accommodate you. This assignment is open-ended, but you may want to consider the following when writing your paper.

1) What is the definition of the disease/allergy?2) What is known and not known about the autoimmune disease/allergy?3) Are there any known or suspected genetic or environmental connections?4) What are the causes and triggers?5) What are effective treatments including lifestyle and home remedies?6) What is its incidence rate?

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HPV Vaccine Assignment

In early 2007 Texas Governor Rick Perry mandated that girls in the public school system entering the sixth grade receive the HPV vaccine, a vaccine that protects women from developing cervical cancer caused by the sexually transmitted virus HPV. Under the mandate, parents could have their children opt out of the vaccine for religious or conscience reasons. Governor Perry, a pro-life, anti-stem cell research Republican received immense criticism from the religious right who argued the mandate violated parental rights and promoted promiscuity. In contrast, he also received enormous praise from women's rights groups who argued his mandate would protect millions of women from developing cervical cancer. The Texas state legislature opposed Perry's executive mandate and passed a law that postponed the implementation of mandatory HPV vaccinations for at least four years. There was enough support in the state legislature for the bill that Governor Perry did not veto it.

As your assignment for the next class, be prepared to debate/discuss whether you agree with Governor Perry's attempt to require the HPV vaccine for public school system girls. Issues to consider include cost of the vaccine, parental rights, vaccine safety, the significance of being able to prevent cancer with a vaccine, etc. After our class discussion, write a half page, single-spaced opinion about your personal views concerning mandatory HPV vaccinations.

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IX. Evaluation of Assessment:

At the end of each class every student wrote one or two questions related to a concept he or she was confused about. I reviewed each question and addressed common misconceptions the following class. Based on the responses I received, it was clear I did not adequately explain how memory B and T cells are formed. I did not focus on clonal selection, but I now think it is important to explain how memory cells and plasma B cells develop. These concepts are critical in understanding adaptive immunity. In addition, it was also clear after reading the student responses that they were interested in learning more about how common drugs such as Tylenol influence the immune response and how various allergies may be controlled with home remedies. I think that being able to incorporate real world examples into the classes is essential for integrating the material together and maintaining student interest.

At the end of the entire course, the students were asked to complete a survey. In the survey several students wrote they enjoyed writing the autoimmune disease/allergy research paper because they were able to learn about a health issue that either affects them or someone they know.

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