BIO 205 Human Immunity

Who Discovered Phagocytes and Studied Human Immunity?

Ilya Metchnikoff

What are the Two Different Types of Immunity?

Adaptive and Innate

Which type of Immunity Involves Factors that Work Generically Against Any Foreign Substance?

Innate Immunity

Which Type of Immunity Develops Throughout Life Via Exposure to Antigens?

Adaptive Immunity

Which Type of Immunity Involves Pattern Recognition of Specific Molecules?

Innate Immunity

What Are the Three Levels of Innate Defense?

First-Line Defenses, Sensor Systems, and Innate Effector Actions

What is the Function of the First-Line Defense System?

To Prevent the Entry of Antigens

How Does the Skin Defend Against Microbes?

By Providing a Tough Exterior that Microbes Cannot Penetrate Easily and Secreting Antimicrobial Substances

What Substance Produced by the Skin is Antimicrobial?

Sweat

How Do Lysozymes Prevent Microbial Growth?

They Break Down the Peptidoglycan in Bacterial Cell Walls

Why is Lactoferrin Considered an Antimicrobial Substance?

It Withholds Iron from Microbes, Thus Inhibiting Growth

What are the Other Types of Antimicrobial Substances Produced by the Body?

Peroxidase Enzymes and Antimicrobial Peptides

What is a Type of Antimicrobial Peptide that Forms Pores in Microbial Membranes?

Defensins

How Do Mucous Membranes Physically Remove Microbes in the GI and Respiratory Systems

Peristalsis of Intestines and the Mucociliary Escalator of the Respiratory Tract

How Does a Person’s Normal Microbiota Defend Against Microbes?

Competitive Exclusion

What are Two Examples of Normal Microbiota Bacteria that Can Predispose a Person to Infections When Disrupted?

Clostridium difficile and Candida albicans

What Does Propionibacterium Do in the Body?

Degrades Lipids and Produces Fatty Acids

What do Blood Cells Originate From?

Hematopoietic Stem Cells

What Induces Blood Cells to Develop? Where?

Colony-Stimulating Factors; Bone Marrow

What Blood Cell Concerns Itself with Host Defenses?

Leukocytes

What Two Mechanisms Do Neutrophils Use to Defend Against Microbes?

Phagocytosis and Release of Antimicrobial Substances and Enzymes

How Do Eosinophils Defend Against Parasites?

Releasing Chemicals that Destroy Eukaryotic Parasites

How Do Monocytes, Macrophages, and Dendritic Cells Defend Against Microbes?

Phagocytosis

What is the Function of Cytokines?

Cellular Communication

Which Cytokines are Important for Both Innate and Adaptive Immunity?

Interleukins

Which Cytokines are Important for Chemotaxis?

Chemokines

How Does Tumor Necrosis Factor Assist with the Immune Response?

Promoting Inflammation and Inducing Cell Death

What is the Function of the Pattern Recognition Receptors?

Detecting Pathogen Associated Molecular Patterns (PAMPs)

Where are Toll-Like Receptors (TLRs) Anchored?

The Membranes of Sentinel Cells

Does Each TLR Recognize the Same “Danger Molecule”?

No

Where are NOD-Like Receptors (NLRs) Found?

The Cytoplasm

Which PRR Binds to Cytoplasmic Proteins to Form Inflammasomes?

NLRs

What Do Inflammasomes Do?

Activate the Inflammatory Response

Where are Rig-Like Receptors (RLRs) Found?

The Cytoplasm

What Do RLRs Do Specifically?

Detech Viral RNA and Produce Interferons

What are Interferons?

Cytokines Released by Infected Cells to Tell Nearby Cells to Produce Inactive Antiviral Proteins

Do Interferons Protect the Cell?

No

What is a Group of Interacting Serum Proteins that Provide a Nonspecific Defense Mechanism?

The Complement System

What Triggers the Classical Pathway?

Antibodies Binding to the Microbial Invaders

What Triggers the Lectin Pathway?

Mannose-Binding Lectin Binding to the Microbial Invaders

What Triggers the Alternative Pathway?

C3b Binding to the Microbial Invaders

What Do All Three Pathways Lead to?

The Formation of C3 Convertase

What Does C3 Convertase Specifically Do?

Split C3 into C3a and C3b

What Does C3b Primarily Function in?

Opsonization

What Does C3 Convertase Do After Splitting C3? What Does this Structure Yield?

Binds to C5 to Form an Enzyme to Split C5; C5a and C5b

What Does C5b Do?

Combines with C6, C7, C8, and C9 to form a Membrane Attack Complex

How Does the Membrane Attack Complex Defend Against Microbes?

Lysing Foreign Cells

What is the Function of C3a and C5a?

Help to Induce the Inflammatory Response

What are the Six Steps of Phagocytosis?

Chemotaxis, Recognition and Attachment, Engulfment, Phagosome Maturation and Phagolysosome Formation, Destruction and Digestion, and Exocytosis

Where Does the Destruction of Microbes Occur?

Phagolysosomes

What are the Four Cardinal Signs of Inflammation?

Redness, Pain, Swelling, and Heat

What Can Swelling Lead to?

Loss of Cell Function

What is a Damaging Effect of Inflammation?

Collateral Damage

What is Apoptosis?

Programmed Cell Death

Does Apoptosis Trigger the Inflammatory Response?

No

What Specifically Causes Fever?

The Presence of Pyrogens

What are the Two Direct Effects of Fever?

Inhibiting Bacterial Growth and Speeding Up the Body’s Reactions

Who Came Up with the Hypothesis of Antitoxins that Lead to the Discovery of the Adaptive Immune Response?

Emile von Behring

What is the Role of the Adaptive Immunity in the First Exposure to an Antigen?

Developing “Memories” of the Antigen

Why is the Secondary Response to an Antigen Stronger?

This Response has Molecular Specificity

What are the Two Primary Lymphoid Organs?

Thymus and Bone Marrow

What is the Function of the Primary Lymphoid Organs?

Producing Lymphocytes

What are the Five Secondary Lymphoid Organs?

Adenoids, Appendix, Lymph Nodes, Spleen, and Tonsils

What is the Function of the Secondary Lymphoid Organs?

Facilitating Antigen Encounters for Lymphocytes

Are Secondary Lymphoid Organs Strategically Located in the Body to Encounter Antigens?

Yes

Why are People Who have their Tonsils Removed More Prone to Upper Respiratory Tract Infections?

Because the Lymphocytes in that Area Do Not Have the Place to Encounter Antigens

When are Lymphocytes Considered Mature?

When they have Specific Receptor Proteins on the Surface

What is Clonal Selection Theory?

The Theory that Explains the Process in Which a Lymphocyte’s Antigen Receptor Binds to an Antigen, Allowing the Cell to Multiply

Where Does the Development Stage of Clonal Selection Occur?

Secondary Lymphoid Organs

Where Do B Cells Develop?

Bone Marrow

What Do B Cells Differentiate Into?

Plasma Cells and Memory B Cells

What Do Plasma Cells Produce?

Antibodies

What Binds to Antigens with a High Degree of Specificity?

Antibodies

Where Do T Cells Mature?

Thymus

What are the Three Subsets of T Cells?

Cytotoxic T Cells, Helper T Cells, and Regulatory T Cells

What is the Function of Cytotoxic T Cells?

Binding to and Killing Infected Cells

What is the Function of Helper T Cells?

Recognizing Antigens on Macrophages and B Cells

Can T Cell Receptors Recognize Free Antigens?

No

Which T Cell Prevents the Immune from Mounting a Response Against “Self” Molecules?

Regulatory T Cells

What Protein Presents the Antigen in All Cells in the Body

Class I MHC Proteins

What Protein Presents the Antigen in Macrophages, B Cells, and Activated T Cells?

Class II MHC Proteins

What Do Cytotoxic T Cells Specifically Respond to?

Endogenous Antigens on Class I MHC Proteins

What Do Helper T Cells Specifically Respond to?

Exogenous Antigens on Class II MHC Proteins

What Type of Receptor is on Cytotoxic T Cells?

CD8 Receptor

What Type of Receptor is on Helper T Cells?

CD4 Receptor

What is the Substance that Elicits an Immune Response Called?

Antigen/Immunogen

What Does the Name “Antigen” Come From?

Antibody Generator

Do Proteins and Polysaccharides Induce a Strong Response?

Yes

What is the Name for the Antigenic Determinants?

Epitopes

Can One Antigen Have Multiple Antigenic Determinants?

Yes

For Which Type of Antigen Do B Cells Require a Signal from Helper T Cells?

T-Dependent Antigens

What are the Four Types of T-Independent Antigens?

Polysaccharide Capsules, Flagella, Lipopolysaccharides, and Molecules with Repeating Subunits

Will B Cells Undergo the Clonal Selection Process in Response to T-Independent Antigens?

No

What Happens to the B Cell that Presents a Peptide that the Helper T Cell Does Not Recognize?

It Becomes Anergic

Which Region of the Antibody Contains the Variable Region and Accounts for Specificity?

The Fab Region

Which Region of the Antibody Contains the Light Chains?

The Fab Region

Which Region of the Antibody is Constant and Allows the Immune System to Recognize Diverse Antibody Molecules (Classes of Antibodies)?

The Fc Region

Which Region of the Antibody Contains the Heavy Chains

The Fc Region

What are the Two Ways the B Cell Compensates for the Imbalance Between the Epitopes and the Antibodies?

By Producing Diverse Antibodies and Expressing Three Gene Segments

How Does the B Cell Express the Three Gene Segments?

By Deleting Sections of DNA