CH. 21: The Immune System: Innate and Adaptive Body Defenses

What are the primary structures (organs) of the immune system?

Red bone marrow & thymus

What is another name for primary structure of the immune system?

Central

What occurs in primary immune structure?

Lymphocyte production

What are the secondary structures (organs) of the immune system?

Lymph nodes, spleen, & tonsils

What occurs in secondary immune structure?

Activation of lymphocytes (they begin to work)

What is another name for secondary structure of the immune system?

Peripheral

What is a pathogen?

A potential disease-causing microorganism

What is the focus of the innate immune system?

Pathogens

What are examples of pathogens?

Bacterium, parasites, & viruses

What is an antigen?

Something that elicits an adaptive immune response (immunogenicity)

What does an antigen react to?

It reacts specifically to the antibodies and cells it provoked (reactivity)

How are antigens built?

Either complete (cancer cell, bacteria, virus, parasite) or just a small part (hapten)

What is an epitope?

The part of the antigen that is bound by an antibody or lymphocyte receptor

What is an allergen?

Antigen causing the allergic reaction

What type of white blood cells are there?

Granulocytes & Agranulocytes

What type of granulocytes are there?

Neutrophils, Eosinophils, & Basophils

How abundant are neutrophils?

Most abundant of all leukocytes

What type of specialist are neutrophils?

Bacteria specialist

What is the method of attack for neutrophils?

They attack bacteria via: degranulation & phagocytosis

How does degranulation work?

Degranulation releases various enzymes and antimicrobial proteins

What does phagocytosis involve?

Phagocytosis involves TLRs and lysosomal enzymes and reactive oxygen species

What type of -phage are neutrophils?

Microphage

How are neutrophils kamikaze microphages?

Main inflammatory cell and they die fighting bacterial infections (pus).

What type of specialist are eosinophils?

Parasite specialist

What type of parasites do eosinophils attack?

They attack endoparasites (especially helminthic worms)

What is the method of attack for eosinophils?

They attach via TLRs, and release granules containing enzymes (lipases, ribonucleases, deoxyribonucleases) and peroxidases

What is the result after eosinophils attack?

In cell apoptosis and necrosis

What is apoptosis?

Death of cell

What is necrosis?

Death of body tissue

What else do eosinophils contribute to?

To allergic reactions as well

What type of -phage are eosinophils?

Microphage

How abundant are basophils? How large is this granulocyte?

Least abundant, but largest granulocyte.

What is the method of attack for basophils?

They release granules containing histamine, heparin, proteolytic enzymes, and various other chemicals (like Mast cells).

What do basophils contribute to?

They contribute significantly to allergic reactions & inflammatory processes.

What type of agranulocytes are there?

Monocyte, T lymphocyte, & B lymphocyte

What is the origin of T and B lymphocytes?

T and B lymphocyte stem cells originate in lymphoid red bone marrow

What occurs during the maturation of T and B lymphocytes?

They begin developing immunocompetence, self-recognition & self-tolerance.

Where do T lymphocytes mature?

Cells destined to become T cells migrate to and mature in the thymus

What do T lymphocytes differentiate into?

Cytotoxic T Cells, Regulatory T Cells, Helper T Cells, Memory T Cells.

What is another name for Regulatory T Cells?

Suppressor T Cells

Which T Cells are CD 4?

Helper T Cells & Memory T Cells

Which T Cells are CD 8?

Cytotoxic T Cells & Regulatory T Cells

Where do B lymphocytes mature?

B cells stay and mature in the red bone marrow

What do T lymphocytes target/do?

Target viral infected cells, cancerous cells, regulate immune activity, etc

What do B lymphocytes differentiate into?

Plasma cells

What do B Lymphocyte produce when activated?

Antibodies

What do antibodies that originate from B Lymphocytes do?

Neutralize, opsonize, agglutinate, & activate complement

What do Monocytes differentiate into?

Macrophages

How large are Macrophages / Monocytes?

They are the largest leukocytes & primary phagocytic cells in the body

What do Macrophages rely on?

On TLRs, but other factors can significantly enhance phagocytosis

What do Free Macrophages do?

They wander through interstitial spaces, blood, and lymph

What do Fixed Macrophages do?

They are permanent residents of some organs (bone marrow, liver, spleen)

What specificity is Innate Immunity?

Non-specific

What is the response time for Innate Immunity?

Immediate response (1st and 2nd lines)

What type of immunological memory does Innate Immunity have?

No immunological memory

What type of non-specific defenses does the innate immune system have?

Barriers, Phagocytes, Fever, Inflammation, Complement, Interferons, & NKCs

What does the innate system use to stop attacks?

Uses the first and/or second lines of defense to stop attacks by pathogens.

What is the 1st line of defense for the innate system?

Surface Barriers which are skin and mucous membranes

What is the main purpose of surface barriers?

To stop bad things from coming in

What else do these surface barriers include for added protection.

Protective chemicals that inhibit or destroy microorganisms

What are the surface barriers in the 1st line of defense?

The Skin & Mucous Membranes

What does the skin provide in the innate immune system?

Acidity, defensin proteins, dermcidin, & sebum

What does the mucous membrane provide in the innate immune system?

Acidity, defensin proteins, enzymes, mucus (mucin), hairs, & cilia

What occurs when surface barriers are breached by wounds?

it triggers an internal 2nd line defenses, which protects deeper tissues

What is the 2nd line of defense for the innate immune system?

Internal Barriers which are WBCs: granulocytes, macrophages, natural killer cells, and antimicrobial proteins

What important role do Internal Barriers play?

These cellular and antimicrobial barriers play important roles in inflammatory responses and fever.

What type of cells are in the 2nd line of defense for innate immune system?

They include granulocytes, macrophages, and NK cells

What are TLRs & PAMPs?

Most innate immune cells utilize Toll-like receptors (TLRs) that identify/bind tightly to structures or patterns (pathogen-associated molecular patterns; PAMPs) on pathogens.

What role do TLRs play in?

TLRs play a central role in triggering immune responses.

What specificity is Adaptive Immunity?

Antigen-specific

What is the response time for Adaptive Immunity?

Lag time from exposure to response (3rd line)

What type of immunological memory does Adaptive Immunity have?

Immunological memory after exposure

What type of response is Adaptive Immunity?

Systemic response

What does Adaptive Immunity provide protection against?

Against specific microbes & pathogens

What type of “immunity” is in Adaptive Immunity?

Cell-Mediated Immunity & Humoral Immunity

What structures are in the 1st line of defense?

Surface Barriers aka skin & mucous membranes

What is the function of the 1st line of defense?

This line of defense inhibits & destroys microorganisms

What structures are in the 2nd line of defense?

Internal Barriers aka granulocytes, macrophages, NK cells, & antimicrobial proteins

What is the function of the 2nd line of defense?

They participate in inflammatory responses & fever

What is the abbreviation for Toll-like receptors?

TLRs

What role do TLRs play?

In triggering immune responses

What do TLRs do to pathogens?

They identify and bind tightly to structures or patterns on pathogen

What are the main phagocytic cells?

Macrophages, neutrophils, & dendritic cells

How do phagocytic cells AIDD?

Adherence

Ingestion

Digestion

Destruction

What is the first step of phagocytosis (Adherence)?

Phagocyte adheres to pathogens or debris using TLRs

How does phagocytosis aid with antigen-presenting / what are antigen presenting cells?

They insert digested pieces of the pathogen into specific membrane proteins for presenting to/activation of other immune cells

What is Opsonization?

Antibodies or complement proteins are opsonin that coat pathogens

What do Opsonization basically do?

Makes pathogens more desirable to destroy

What does Opsonization stick to?

stick to pathogenic cells like glue, making them difficult to adhere

What do interferons do?

Cells infected with viruses can secrete IFNs that “warn” healthy neighboring cells.

What are IFN-a(interferon alpha) & IFN-b(interferon beta) secreted by?

Secreted by virus-infected cells

What is the purpose of IFN-a & IFN-b?

They stimulate production of anti-viral proteins that block viral reproduction and degrade viral RNA

What do IFN-a & IFN-b activate?

NK cells

What are IFN-g(interferon gamma) secreted by?

Secreted by T cells, NK cells, & macrophages

What is the purpose of IFN-g?

Widespread immune mobilizing effects

What do IFN-g activate?

Potent activator of macrophages, but also activates NK cells and T cells.

What do Interferon proteins increase?

Resistance to viral infections & stimulate Macrophages & NKCs

What is a Complement System?

About 20 blood proteins that circulate in blood in inactive form

What proteins does Complement System include?

Proteins C1–C11

What does the Complement System enhance?

Enhances inflammation and directly destroys bacteria & Enhances both innate and adaptive defenses.