Lesson K: Chapter 14 & 15 Innate & Adaptive Defenses

Neutrophils

-1st at infection -Work quick, but messy -Produce pus.

Complement proteins

-Activated by antiboides on infected cells. -MAC (Cytolysis: bursting of microbe d/t inflow of extraceullar fluid) -Help degranulate mast cells & basophils -Act as opsonins (coat pathogen to make tasty for phagocyte cell) -Help with vasodilation and phagocytosis (attract phagocytes)

Basophils

-Allergic reactions -Granules can release histamine resulting in inflammation.

What are the 6 ways that antibodies will rid the body of microbes?

-Coat the surface of a bacterium preventing functions & reproduction -Opsonization: Bind to microbes encouraging phagocytosis. -Neutralization: Fill surface receptors/active site;prevent it from acting normally. -Antitoxin: Special Ab;neutralizes bacterial exotoxins. -Agglutinate: immobilizes microbes; enhances phagocytosis -Rupture: Interaction of antibody with complement.

IgA

-Dimer (most effective form) -In secretions; most common in saliva, tears, mucous, breast milk. -Mucosal protection -Prevents attachment

Eosinophils

-Helminth infections & little in allergic reactions.

What do vaccines do?

-Low level adverse side effects or toxicity & not cause serious harm -Protect against exposure to natural & wild forms of pathogen. -Stimulate both Ab & cell-mediate response. -:Long-term;lasting effects (memory) -Numerous doses/boosters not required. -Inexpensive, long self life, easy administration.

IgD

-Monomer -In blood, lymph, & B cells -Initiate immune response on B cells -Exact function unknown.

IgG

-Monomer -Most common & longest lasting -Trigger complement system -Enhance phagocytosis -Neutralize toxins & viruses -Protect fetus & newborn

IgE

-Monomer, slightly larger than IgG -On mast cells, basophils, and in blood -Allergic reactions -Lysis of parasitic worms.

IgM

-Pentamer -Fix complement -In blood, lymph, & B cells -Agglutinates microbes -First Ab produced in response to infection.

What are the attributes of the adaptive immunity?

-Specificity-3D shape is everything for binding -Inducibility-Activation only in response to specific pathogens. -Clonality-Active immune cells proliferate into clones (army) -Unresponsiveness to self-self-tolerance, no auto-immunity -Memory-responds faster upon next exposure to pathogen.

How do vaccines work?

-Stimulate a primary immune response that primes the immune system for future exposure to a virulent pathogen. -If the pathogen later enters the body, the secondary immune response will be immediate, powerful, & sustained.

Monocytes

-out of bloodstream they are macrophages. -2nd at site of infection -Clean up after neutrophils.

Third line of defense

1) B cells 2) T cells

What are the steps of phagocytosis?

1) Chemotaxis of phagocyte to microbes 2) Adherence 3) Ingestion of microbes 4) Fusion of a series of vessicles, including lysosomes 5)Killing of microbes by enzymes & other chemicals 6) Elimination (exocytosis)

How does a phagocytic cell get to the site of injury?

1) Injured tissue release cytokines; leukocytosis-increase WBC 2) Cytokines put up CAM 3) WBC will marginate (stick to vessel wall). 4) WBC will squeeze through vessel wall-diapedesis 5) WBC will use positive chemotaxis (cytokines) to find microbe & exact spot of injury.

Second line of defense (innate/nonspecific)

1) Phagocytes: Ex: Neutrophils & Macrophages 2) Inflammation: Heat, Redness, Swelling, Pain 3) Fever: Pyrogen (exogenous (organism release pyrogen) or endogenous (WBC release pyrogen)) 4) Antimicrobial proteins: Complement proteins & interferons 5) NK cells: Lymphocyte that attacks non-self antigens (bacteria, tissue/organ, infected cell, cancer) -Burst of Perferin (poke holes, causing cell to lyse)

First line of defense (innate/nonspecific)

1) Physical barriers: Skin & mucosa memebrane -Mucous traps m/o -Skin decreases pH 2) Chemical barriers: Tears, sweat, saliva have lysosomes (break down bacteria) -Urination and defication remove bacteria. -Stomach and vagina decrease pH.

What are the basic functions of the lymphatic system?

1) Provide an auxiliary route for the return of extracellular fluid to the circulatory systems proper. 2) Act as a "drain-off" system for the inflammatory response. 3) Provide surveillance, recognition, and protection against foreign materials through a system of lymphocytes, phagocytes, and antibodies.

What is the overall function of inflammation?

1) To mobilize & attract immune components to the side of injury 2) To set in motion mechanisms to repair tissue damage & localize & clear away harmful substances. 3) To destroy microbes & block their further invasions.

What are the actions of interferons?

1) Virus infects cell. 2) Viral replication in cell triggers transcription & translation of alpha or beta interferon depending on type of host cell. 3) Interferon is released, diffuses to neighborning uninfected cells, & binds to receptors. 4) Binding triggers transcription & translation of inactive antiviral proteins (AVPs). 5) Meanwhile, the infected cell dies & releases the virus. 6) When the 2nd cell becomes infected with viruses, double-stranded RNA of the virus activates AVP. 7) Active AVPs degrade mRNA & bind to ribosomes, which stops protein synthesis & viral replicaiton.

What are the benefits of fever?

A) Increase BMR (speed up phagocytes & healing) B) Liver & spleen to hold onto iron & zinc needed for microbial replication. C) Increase microbial replication, causing resources to be used up, leading to population collapse.

What is a fever?

Abnormall elevated body temperature.

What do B cells produce?

Antibodies

Ab

Antibody

APCs

Antigen present cells (Have epitope on MHC to activate 3rd line of defense)

BCR

B cell receptor

Adaptive Immune System

Body's ability to recognize & defend itself against distinct invaders & their products.

CAM

Cell adhesion markers

CD

Cluster of differentiation

Active

Creates immune response

What are the different types of T cells and their functions?

Cytotoxic T cell- Directly kills other cells (endogenous antigens) Helper T cell- Helps regulate the activities of B cells (exogenous antigens) & cytotoxic T cells. —involved in activating macrophages. Regulatory T cell- Represses adaptive immune responses. -Carry CD4 markers -Act to control inflammatory process -Prevent autoimmunity. -Make sure immune response does not inappropriately target normal biota.

What is the role of NK cells?

Differentiates between self vs. non-self cells.

What is fever caused by?

Exogenous (viruses, bacteria, protozoans, & fungi) or endogenous (monocytes, neutrophils, & macrophages) pyrogens -Reset hypothalamus upwards.

What kind of immunity is each of the 3 lines of defense?

First two lines are innate or nonspecific, whereas the third line is specific or acquired immunity.

What will cytotoxic T cells attack?

Foreign peptide complexed with self MHC-I

What are the cardinal signs of inflammation?

Heat, redness, swelling, pain

How are each of the cardinal signs of inflammation caused?

Heat: Increased BMR Redness: More blood to the area Swelling: Exudate: protein rich fluid that leaks out of blood vessels. Pain: Caused by prostaglandins.

What is the function of each of the cardinal signs of inflammation?

Heat: Tissues heal quicker & phagocytic cells work faster. Redness: More WBC, nurtiens, O2, and removes waste. Swelling: Exudate has healing properties, clotting factors, & dilutes toxins Pain: To make organism aware they have been hurt.

What kinds of pathogens will activate what kinds of lymphocytes?

Humoral: B cell, Ab, extracellular pathogen Cell-mediated: T cell, intracellular pathogen.

What is the purpose of fever?

Increase BMR (Speed up phagocytes & healing) Liver & slpeen hold onto iron & zinc needed for microbial replication. Increased microbial replication causes all resources to be used up leading to populatioin collapse.

Artificially acquired passive immunity

Injection of Ab from animal/person immune to disease.

Artificially acquired active immunity

Injection of Ag (vaccination)

What is the difference between first and second exposure to an antigen?

Innate immunity is quicker to respond on first exposure, however adaptive immunity is quicker to respond on second exposure.

What are all of the purposes of interferons and complement proteins?

Interferons: Used in therapy against certain viral infections & cancer. Involved in defenses against other microbes & in immune regulation & intercommunication. Complement Proteins: Work together to destroy bacteri and viruses. Produce a cascade reaction.

LPS

Lipopolysaccharide

What kind of organisms will be exposed on each MHC class I & II?

MHC I: Endogenous MHC2: Exogenous

Where are MHC class I & II found?

MHC I: Nucleated cells MHC II: macrophages, dendritic cells, & B cells.

MAC

Membrane attack complex

M/o

Microorganisms

What are the antigens and give examples of them?

Molecules the body recognizes as foreign & worthy of attack -Recognized by 3D regions -Include: bacteria, protozoa, certain proteins in foods, component of serum & RBC from other individuals.

How do B cells get activated?

Must interact with a T helper cell that bears receptors for antigen from the same microbe.

What are the types of acquired immunity?

Naturally: Response against antigens encounter in daily life. Artificially: response to antigens introduced via vaccine.

Innate Immune System

Nonspecific response; Nonspecific barriers that impede pathogens from entering the body or multiplying; Internal and external barriers.

Passive

Passively receive antibodies from another individual.

PRR

Pathogen recognition receptor

PAMPs

Pathogen-associated molecular patterns; structures found on foreign microbes but NOT on self-cells

What does perferin do?

Poke holes in cell wall causing cell to lyse.

What are epitopes?

Portion of the antigen molecule recognized & responded by a lymphocyte.

Interferons

Proteins released by virally infected cells that let neighboring uninfected cells know there is an infection. -When uninfected cell is infected, will produce antiviral proteins to block viral synthesis.

Why are helper T cell so important?

Recognize a specific epitope & are self tolerant.

What is the role of mast cells?

Release histamines (Vasodilation)

Naturally acquired active immunity

Results from infection

How do cytotoxic T cells attack?

Secretion of performing & granzymes.

Lymphocytes

T cells, B cells, & NK cells.

Where do the different lymphocytes gain maturity?

T cells- Thymus B cells- Bone marrow

What does it mean for the different lymphocytes to be mature?

T cells-Immunocompetent B cells-Produce antibodies necessary to fight off infections and produce memory to specific antigens.

TCR

The T cell receptor on the majority of T cells - it recognizes antigen-MHC complexes

What are the functions of the organs of the lymphatic system?

Thymus: site of T-cell maturation Lymph nodes (glands): Filter out materials that have entered the lymph and providing appropriate cells & niches for immune reactions. Spleen: Filters worn-out RBC from circulation & pathogens from blood, then having them killed by resident macrophages. MALT: Provides immune functions against intestinal pathogens & produces some types of antibodies.

TLRs

Toll-like receptors (TLR is a type of PRR on phagocytes that can detect PAMPs)

Naturally acquired passive immunity

Trans-placental or via colostrum

What is pus?

Viscous, opaque, usually yellowish matter formed by an inflammatory infection. -Consists of serum exudate, tissue debris, leukocytes, & microorganisms.

What are the different components of blood and roles each play in maintaining the immune system?

Whole blood: -Formed elements: WBC (leukocytes), platelets (clotting), RBC (erythrocytes/carry O2) -Plasma (Water, nutrients, glucose, fats, wastes, hormones, bicarbonates, clotting factors)

MHC

major histocompatibility complex; found in the plasma membrane; alerts T cells that a cell is infected w/ a virus