Ch. 21 The Immune System (innate and adaptive body defenses)

(Internal Defenses of Innate Immunity Second line of defense) What is inflammation triggered in response to?

Inflammation is triggered in response to infection or an injury. The four classic signs are redness (rubor), Swelling (tumor), heat (Calor), and pain (dolar).

What are the characteristics of innate immunity?

Innate immunity is called non-specific immunity because all pathogens are treated the same way. It does not have specific molecular recognition. No "memory" of past infections. Always present and working, it contains and destroys most pathogens.

(Internal Defenses of Innate Immunity Second line of defense) What is the Complement in innate immuntiy?

A collection of more than 20 plasma proteins. Made in the liver and often named C#. Always found in the blood in an inactive state. 3 ways to activate Complement. Classical Pathway, Lectin Pathway, and Alternative Pathway.

(Internal Defenses of Innate Immunity Second line of defense) What is a fever?

A fever is an abnormally high body temperature. Safe temperature is lower than 103* in adults for two reasons: It causes the liver and the spleen to sequester iron and zinc. Needed for bacterial growth. Increases metabolic rate of tissues, immune system works faster and tissues repair faster. Pyrogens: Chemical compounds that cause a fever, the hormone interleukin-1 and the bacterial product lipopolysaccharide (LPS)

(Internal Defenses of Innate Immunity Second line of defense) What is the Alternative pathway?

Activation of the complement spontaneously occurs. Bacteria lack complement inhibitors all human cells have.

(Anitbodies: The Humoral immune response) What are antibodies the tools of?

Antibodies are the tools of B cells. Y shaped protein, weighs about 150kDa also called immunoglobins (Igs)

(Internal Defenses of Innate Immunity Second line of defense) What is the Classical pathway in the Complement?

Antibodies on the surface of the target cell bind and activate complement proteins.

(Mechanisms of antibody protection) What do antibodies tag antigens for?

Antibodies tag antigens for destruction by innate immune system.

(Mechanisms of antibody protection) What is Opsonization?

Antibody is attached to the object it makes it easier to phagocytize, enhances phagocytosis

(Mechanisms of antibody protection) What is Neutralization?

Antibody physically blocks toxin or virus from attaching to the cell. Works against only small antigens.

(Mechanisms of antibody protection) What is ADCC?

Antibody-dependent cellular cytotoxicity (ADCC) natural killer cells and eosinophils will kill cells labeled with antibody.

(Mechanisms of antibody protection) What is Agglutination / Precipitation?

Antobodies have two identical binding sites: Allows them to ling targets and can cause clumping.

(Internal Defenses of Innate Immunity First line of defense) What are Eosinophils?

Attack large parasites, release AMPs, positively charged disrupts membranes. Releases pro-inflammatory signaling molecules, example histamine. Can perform phagocytosis, targets usually too large.

(Adaptive Immunity) what are the characteristics of B Cells?

B Cells develop to maturity in the bone marrow, they produce antibodies. They differentiate into plasma cells, large, mature antibody secreting cells. Antibodies fight extracellular pathogens.

What does innate immunity use to work?

Barriers: Thin Skin and Mucous membranes. Cells: Phagocytes and Natural Killer cells. Antomicrobrial Proteins and Fever.

(Internal Defenses of Innate Immunity First line of defense) What are the cells that specialize in signaling?

Basophils and Mast cells. Both derived from pluripotent hematopoietic stem cells. Granules contain signaling molecules that initiate inflammation with histamine and prostaglandins. Attract other immune cells, with interleukin-8 and they are anticoagulants, using heprin.

(Internal Defenses of Innate Immunity Second line of defense) What is CRP?

C-reactive protein (CRP) produced by the liver during an inflammatory response. Assists complement in opsonization. Used as blood-test marker for acute inflammation. Level increases 50,000X during inflammation.

(Adaptive Immunity) what is the mechanism of killing by Tc?

CD 8 T cells kill target cells using perforin and grnzymes, similar to natural killer cells. Only kill cells that show signs of infection or abnormal growth.

(Adaptive Immunity) what are the characteristics of CD 8 T cells?

CD8 T cells are cytotoxic T cells, they destroy abnormal human cells, infected with intracellular pathogens that are cancerous, Use the T cell receptor to recognize antigens on abnormal target cells.

What are the characteristics of adaptive immunity?

Called Specific immunity because it has the ability to recognize and remember specific pathogens, it has molecular recognition, it has Memory. Delayed responses, takes a few days to fully activate. More powerful than innate immunity.

What are the tools of adaptive immunity?

Cells: Lymphocytes B cells and T cells. Proteins: Antibodies.

What are Tears and Saliva for in the innate immune system?

Constantly rinses the eyes and mouth. Also contains Lysozyme.

(Adaptive Immunity) What does each antibody recognize?

Each antibody recognizes only one epitope of an antigen through its variable region. Specificity is random and is set forever durig lymphocyte debelopment, antibody A was made by B Cell A. Each antigen contains many epitopes, many recognize it from different angles.

(Adaptive Immunity) What does each antigen contain?

Each antigen contains many epitopes, epitopes is a place on an antigen where an antibody binds, an appropriate epitope is about 7 amino acids long.

(Internal Defenses of Innate Immunity Second line of defense) What is the Activation Cascade?

Each complement protein activates the next. Usually by cleaving it into two fragments, a and b. Large fragments (b) attach to the surface of a foreign cell, targeting destruction. Small fragments (a) float away and act as signaling molecules, they call in reinforcements.

How does Innate and Adaptive immunity work together?

First Line of Defense: Innate Immunity. Contains Intact Skin, Mucous membranes and their secreations, and normal microbiota. If Pathogen still gets through second line of defense kicks in. Second Line of Defense: Innate Immunity, Natural Killer cells and phagocytic white blood cells, Inflammation, fever, and antimicrobrial substances. If pathogen still doesnt get killed, third line of defense kicks in. Third Line of Defense: Adaptive Immunity, Specialized Lymphocytes T cells and B cells, and Antibodies.

What does normal microbiota do in the innate immune system?

Helpful bacteria, out compete harmful bacteria. Prevents Infection. Examples are E.Coli it lives in the GI tract. High numbers prevent invading bacteria from finding a place to live.

(Internal Defenses of Innate Immunity Second line of defense) What is the Lectin Pathway int he Complement?

Lectin proteins made in the liver bind sugars in the bacterial cell wall. Than activate the complement proteins.

(Internal Defenses of Innate Immunity Second line of defense) How do leukocytosis mobilize phagocytes.

Leukocytosis: Signaled by prostaglandins, increases the number of neutrophils in the blood for 5 hours. Margination: Neutrophils attracted by chemical signals like IL-8 cling to capillary walls. Diapedesis: NEutrophils leave the capillaries. Chemotaxis: Neutrophils move to damaged area following IL-8 concentration gradient.

(Internal Defenses of Innate Immunity Second line of defense) What do macrophages take over for?

Macrophages take over for neutrophils, monocytes follow neutrophils into site of infection. Also perform margination diapedesis and chemotaxis. The Differentiate into macrophages once in the tissue. Remove deadly body cells, and foreign material. Clear stage for repair.

(Internal Defenses of Innate Immunity Second line of defense) How does Interferon A and B warn of near by viral infection?

Made in infected host cells, adnd sent to nearby cells. They tell the uninfected cell to make antiviral proteins, proteases and nucleases that inhibit viral reproduction, example is the oligoadenylate synthetase, an enzyme that degrades viral mRNA. Also activate NK cells.

(Internal Defenses of Innate Immunity Second line of defense) What is the mechanism of inflammation?

Mechanism of inflammation: The signals, tissue damage causes mast cells to release signals, like histamine, IL-8, prostaglandins, heparin, NO, and others.

(Internal Defenses of Innate Immunity Second line of defense) What is MAC?

Membrane attack complex (MAC). End result of complement activation cascade. A ring of 10-16 molecules of C5b-9 punches a hole in the target cell membrane, causes the cells to lyse.

(Internal Defenses of Innate Immunity First line of defense) What are the characteristics of monocytes?

Monocytes develop into macrophages. Travel inactively in the blood, they migrate to infected tissues, differentiate into free macrophages. Used for final debris clean up by Voracious phagocytes. Live longer than neutrophils, activate an adaptive immune response.

What is the Ciliary Escalator in the innate immune system?

Mucous membranes of the respiratory tract and trap microbes, and push them out, also contains lysozyme, contains defensins another AMP

(Internal Defenses of Innate Immunity Second line of defense) What is the Strategy of the second line of defense?

Neutralize any microbes that get past the first line of defense. By Cells and Proteins.

(Internal Defenses of Innate Immunity First line of defense) What do Neutrophils do before Phagocytosis?

Neutrophils kill before phagocytosis. Granules contain destructive proteins, Proteases, defensisns (AMPs), Enzyme that produce toxic forms of oxygen. Production of theses toxic compounds is know as the respiratory (Oxidative) bursts.

(Internal Defenses of Innate Immunity Second line of defense) What is an abscess?

Occurs when prolonged infection, inflammation could not clear infection. Dead tissue, bacteria and WBC accumulate forming pus. Collagen fibers wall off the area forming the abscess. Surgical drainage sometimes necessary.

(Internal Defenses of Innate Immunity Second line of defense) What are the two ways that the complement activation leads to target cell death?

Opsonization: Helps Phagocytes grab a hold of the cell. Membrane attack complex: Pokes holes in bacterial plasma membrane.

(Adaptive Immunity) What is the strategy of adaptive immunity?

Recognizes and remembers specific pathogents. Tools of attack: The lymphocytes: B Cells Produce antibodies AKA humoral cells T Cells attack abnormal cells, secrete signaling molecules, AKA cellular immune response,

(Adaptive Immunity) What are CD 4 T Cells?

Release signaling proteins that activate other immune cells, B cells and Macrophages. Release hormones called cytokines. There are several subtypes of Th cells.

(Internal Defenses of Innate Immunity First line of defense) What are the characteristics of Natural Killer (NK) Cells?

Special type of granular lymphocyte (Tcells) not part of adaptive immunity. They kill abnormal human cells, virally incfecected and cancer cells. Kill without Phagocytosis, and kill with out molecular recognition of foreign orgnaism, they kill cells lacking self atingen called MHC.

(Internal Defenses of Innate Immunity First line of defense) what are the characteristics of Mast Cells?

Stationary in connective tissues, famous for releasing chemical signals that initiate inflammation, with histamines and protaglandins.

What are Gastric Juices used for in the innate immune system?

Stomach contains acid and enzymes that break down protein, it is a hostile environment for most microbes. Contains Acid Mantel=Low pH of skin, vagina, and stomach is protective.

(Anitbodies: The Humoral immune response) What are the antibodies structurally broken into?

Structuarally broken into 2 regins: The Variable Region: Top "V" contains the antigen binding site, different in every B cells. Constant region: The bottom "stem", it determines what class of antibody it is (5 classes)

(Anitbodies: The Humoral immune response) What is Immunoglobulin A (IgA)?

Structure: Dimers protected by J chain Location: fount in body secretions. Function: Prevents pathogens from entering the body.

(Anitbodies: The Humoral immune response) What is Immunoglobulin G (IgG)?

Structure: Mnomer Location: Plasma, relatively long lastng. Function: Targets ccompliment NK cells, naeutralizes pathogens, agglutination. ONLY CLASS ABLE TO CROSS THE PLACENTA.

(Anitbodies: The Humoral immune response) What is Immunoglobulin E?

Structure: Monomer Location: Surface of mast cells. Function: Trigger histamine release, famously in allergies.

(Anitbodies: The Humoral immune response) What is Immunoglobulin D (IgD)?

Structure: Monomer Location: Surface of maturing B cells, very low in plasma. Function: First to bind antigen upon B cell activation.

(Anitbodies: The Humoral immune response)What is Immunoglobulin M (IgM)?

Structure: Pentamer Location: Plasmal first class secreted by newly activated B cells. Function: 1st secreted, Excellent at afflutination, activates complement.

(Adaptive Immunity) What are Antigens?

Substances that cause an immune response by the body. Usually macromolecules from foreign organisms, non-self proteins.

(Adaptive Immunity) What are the Characteristics of T cells?

T cells develop into maturity in the thymus. They produce the T cell receptor (TCR) allows cell to differentiate self from non-self. Binds to the antigen only when presented by MHC molecules. Two classes of T cells: CD 8 Cells--> Cytotoxic T cells (Tc) CD 4 Cells--> Helper T cells (Th)

What is the function of the immune system?

The Function of the immune system is to protect the body from disease. From Pathogens, the organisms that cause disease. Tow arms of the immune system work together to protect the body, Innate immunity and the adaptive immune system.

(Internal Defenses of Innate Immunity First line of defense) What do Basophils do?

The circulate in the blood and they are the rarest granulocyte.

What does urine do in the innate immune system?

The flow sweeps away the microbes.

(Internal Defenses of Innate Immunity Second line of defense) What is the mechanism of the NK cell killing?

The mechanism of NK cell killing, is NK cells release 2 proteins, proforin and granzymes. Perforin punches holes in the target cell membrane. Granzymes induce the cell to undergo apoptosis, programmed cell death.

(Internal Defenses of Innate Immunity First line of defense) What are the Phagocytes?

The phagocytes ingest microbes, and cellular debris called phagocytosis. Consist of three cell types Neutrophils, Macrophages (from Monocytes) and Eosinophils.

What does the skin do for innate immunity?

The skin is a tightly sealed protective barrier. It constantly sheds keratinized cells and keeps the microbes colonizing. Eccrine sweat lowers the pH, contains Lysozyme that digests the peptidoglycan cell walls. Also contains Broad Spectrum antimicrobial peptide (AMP)

(Internal Defenses of Innate Immunity First line of defense) What are the characteristics of Neutrophils?

They are Granulocytes, most numerous immune cell. First cell to attack invading pathogens, they migrate into infected tissues from the blood vessels. Typically destroy themselves when they attack targets they are short lived.

(Internal Defenses of Innate Immunity First line of defense) What is the strategy of innate immunity?

To neutralize any microbes that get past the first line of defense. Contains cells and proteins.

What is the strategy for innate immunity?

To prevent microorganisms from enterring or remaining in the body, by physical barriers, chemical barriers and Out-Compete harmful microbes.

(Internal Defenses of Innate Immunity Second line of defense) What is the purpose of inflammation?

To prevent the spread of infection to nearby tissues. Dispose of cell debris, and pathogens. Activate adaptive immune system, and sets the stage for repair.

(Internal Defenses of Innate Immunity Second line of defense) What are the effects of released signals?

Vasodilation, it increases the blood floe caused by Prostaglandins and NO, leads to heat and redness, bringing in more white blood cells. Increased Capillary permeability, Caused by histamine and heparin. Exudate leaks fluid into the tissue. Foreign material into the lymphatic capillaries. Clotting factors eventually wall of site of infection, leads to swelling and lots of pain.

(Internal Defenses of Innate Immunity Second line of defense) How does Opsonization work?

When C3 is activated it splits into 2 proteins C3a and C3b. C3b coats the surface of the microbes. Phagocytes have C3b receptors in their plasma membrane to grab onto C3b and pull in the target cell.

(Mechanisms of antibody protection) What is Complement activation?

classical activation pathway. IgG and IgM binding to antigen can start the activation cascade for compliment.