BIO220 Lecture Exam 5 (Ch 14, 15, 16, 17)

First Line of Defense

-Any barrier that blocks invasion at the portal of entry

-nonspecific & innate

-physical & chemical barriers

First Line of Defense - Physical or anatomical barriers examples

Skin and mucous membranes of respiratory, urogenital, eyes, and digestive tracts

First Line of Defense - Nonspecific Chemical barriers examples

•Sebaceous (oil) secretions

•Lysozyme

•High lactic acid and electrolyte (salt) concentration in sweat

•Skin's acidic pH

•Hydrochloric acid in stomach

•bile of intestines

•Semen antimicrobial

•Vagina has acidic pH

•Urine is antimicrobial

Second Line of Defense

Protective cells and fluids;

inflammation and phagocytosis

-nonspecific & innate

Second Line of Defense - examples

phagocytosis, inflammation, fever, antimicrobial proteins (interferon)

Third Line of Defense

-acquired with exposure to foreign substance;

-produces protective antibodies and creates memory cells (includes lymphocytes)

-specific

-adaptive

Functions of a healthy functioning immune system

1. Surveillance of the body

2. Recognition of foreign material

3. Destruction of foreign material

What are the five types of leukocytes (WBCs)?

Neutrophils

Lymphocytes

Monocytes

Eosinophils

Basophils

mnemonic: Never Let Monkeys Eat Bananas (in order of prevalence in the blood)

Neutrophils

2nd line of defense

-general phagocytosis

Eosinophils

2nd line of defense

-destruction of large eukaryotic pathogens (worms/fungi)

Monocytes

2nd line of defense

-phagocytosis

-when migrating into tissues, they differentiate into macrophages

Basophils

2nd line of defense

-releases histamine (in immediate allergic reactions)

Lymphocytes

3rd line of defense

B & T Cells

B cells

make memory cells

mature in red bone marrow

T cells

mature in the thymus

Types of leukocytes that perform phagocytosis?

neutrophils & monocytes

What are the functions of a healthy immune system?

-surveillance of the body

-recognition of foreign material

-destruction of entities deemed to be foreign

Fever

•Initiated by circulating pyrogens which reset the hypothalamus to increase body temperature;

-signals muscles to increase heat production and vasoconstriction

Fever - benefits

-Inhibits multiplication of temperature-sensitive microorganisms

-Impedes nutrition of bacteria by reducing the available iron

-Increases metabolism and stimulates immune reactions and protective physiological processes

pyrogens

substances that cause fever

Lymphatic system - functions

1. Provides an auxiliary route for return of extracellular fluid to the circulatory system

2. Acts as a drain-off system for the inflammatory response

3. Renders surveillance, recognition, and protection against foreign material

spleen- functions

-structurally similar to lymph node;

-filters circulating blood to remove worn out RBCs and pathogens

bone marrow - functions

how all blood/immune cells are made

stem cells

undifferentiated/unspecialized cells that retain the ability to become a wide variety of specialized cells

diapedesis

The movement of white blood cells from the blood across blood vessel walls into tissues.

chemotaxis

•migration in response to specific chemicals at the site of injury or infection

How Do WBCs Know Self vs. Foreign (Non-self)?

•WBCs interact with the markers on the surface of cells.

•If these markers are deemed to be "self," the cell is bypassed and left alone.

•If these markers are deemed as foreign (non-self), the cell/virus/particle is ingested and destroyed.

interferon

•Small protein produced by certain white blood cells and tissue cells

•Bind to cell surfaces and induce expression of antiviral proteins

•Inhibit expression of cancer genes

complement proteins

•Consists of 26 blood proteins that work in concert to destroy bacteria and viruses

Antigen (Ag)

Anything that the body views as foreign and provokes a response from the T cells and B cells.

Examples of Antigens

bacteria, viruses, eukaryotic pathogens - whole cells/particles or parts of them, allergens such as pollen, animal dander, mold spores, etc., even cells from another person.

natural active immunity

production of one's own antibodies or T cells as a result of infection or natural exposure to antigen;

creates memory, takes time, and is lastingf

natural passive immunity

acquired by a child through placenta and breast milk

artificial active immunity

vaccines

artificial passive immunity

Injection of an antiserum derived from an immune individual; does not create memory, acts immediately, and is short term

how are B cells activated?

•B cells are activated by T helper cells.

B Cells - what determines the shape of the antibodies & what info the memory cells made will have?

by the shape of the antigen they are exposed to and what memory the memory cells will have.

T helper cells - function

•In charge of the immune system; generals of the army.

Cytotoxic T cells - function

•Put toxic chemicals on foreign invader target cells to kill them

•Put toxic chemicals on our own cells that are infected (to prevent pathogens from completing their multiplication cycle and spreading) --> kills them

Major Histocompatibility Complex (MHC) also known as

HLA

MHC or HLA - related to grafts and transplants

must be matched as closely as possible for grafts/transplants to minimize the recipient's immune system from seeing the donated tissue/organ as being foreign (and thus, attempting to destroy it as it would a pathogen).

MHC - class I

-found on ALL cells

-how all your cells know that they belong together in one body

-required for T cells

MHC - class II

-found on macrophages or B cells

-recognition of self by the immune system and the rejection of foreign tissue

What are B-Cell Receptors called?

immunoglobulins

what are the B cell receptors called when they are released/secreted from the B cell membrane?

antibodies (Ab)

what are immunoglobulins (Ig) used for?

-proteins that act as antibodies

-gamma globulin portion of blood

Shape of immunoglobulins

Y shaped

What are the five types of immunoglobulins?

IgG, IgA, IgM, IgE, IgD

(remember mnemonic GAMED)

IgG

-most abundant (Greatest plasma concentration)

-Goes across placenta (mom (G) -> baby (g))

-Gets released as an Ab (antibody)

IgA

-mucosal immunity, secretions (sAliva, teArs, breAst milk)

-gets released as an Ab

IgM

-first antibody produced (Made first)

-largest of the antibodies (Mega)

-gets released as an Ab

IgE

-allergEE (allergy)

-causes mast cells & basophils to release histamine

-active in some parasitic worm infections

-gets released as an Ab

IgD

-serves as a receptor for antigen on B cells

-remains a receptor in B cells

monoclonal antibodies

are laboratory-produced proteins that mimic the body's natural antibodies. They are designed to bind to specific targets, known as antigens, on the surface of cells or molecules.

What are the main receptors T cells have?

CD4 & CD8

Type of T cell that has CD4 receptors

T helper cells

Type of T cell that has CD8 receptors

Cytotoxic T cells

allergen

antigen that causes an allergic reaction

What is the Primary immune response?

produces IgM and gradually increases IgG production, but it is slow

What is the Secondary immune response?

(after contact with the same antigen) produces a faster stronger response due to memory cells that were made during the primary response

What do vaccines do?

artificially cause the immune system to produce a primary and secondary response, so that upon subsequent response with an actual pathogen, the immune response clears the pathogen so fast that you usually don't even realize you've come in contact with it.

What are Superantigens?

Produce an overwhelming immune response with drastic consequences:

-Release of cytokines

-Blood vessel damage

-Toxic shock

- Multiorgan damage

Four ways vaccines are prepared

1. Killed whole cells or inactivated viruses

2. Live, attenuated cells or viruses

3. Antigenic molecules derived from bacterial cells or viruses

4. Genetically engineered microbes or microbial agents

Acellular/subcellular vaccines (subunit if virus)

-capsules

-surface proteins

-endotoxins

Adjuvant

a substance that enhances the body's immune response to an antigen

What is the reasoning behind Herd Immunity?

the resistance to the spread of a contagious disease within a population that results if a sufficiently high proportion of individuals are immune to the disease, especially through vaccination.

-If you vaccinate most people, it will make it less likely that any person will get the pathogen (protects most everyone)

Allergy/hypersensitivity

-an exaggerated, misdirected expression of immune responses to an allergen (antigen)

Autoimmunity

abnormal response to self Ag

Autoimmunity examples

•Disruption of function can be systemic or organ specific:

-Systemic lupus erythematosus

-Rheumatoid arthritis

-Endocrine autoimmunities

-Myasthenia gravis

-Multiple sclerosis

Immunodeficiency

deficiency or loss of immunity

ex. AIDS, born with a genetic error, missing immune system (SCID)

Why is cancer able to spread without much interference from the immune system?

Underreaction to antigenic stimulation leading to loss of immunity, which can lead to a lack of surveillance resulting in cancer.

Hypersensitivities - Type I

Immediate

-ex. hay fever, asthma, anaphylaxis

-mechanisms: IgE, basophils

Hypersensitivities - Type II

Antibody-mediated

-ex. blood type incompatibilities, pernicious anemia, myasthenia gravis (some autoimmune disease)

-mechanisms: IgG & IgM antibodies, complement

Hypersensitivities - Type III

Immune complex mediated

-ex. rheumatoid arthritis, serum sickness, systemic lupus (some autoimmune disease)

-mechanism: IgG

Hypersensitivities - Type IV (4)

T Cell-mediated

-mechanisms: delayed hypersensitivity & cytotoxic reactions in tissues

-ex. infection reactions, contact dermatitis, graft rejection, some autoimmune diseases

Which of the 4 types of hypersensitivities can result in autoimmune diseases?

2, 3 & 4

Anaphylaxis

a systemic, often explosive reaction that involves airway obstruction and circulatory collapse

Sensitizing Dose (Type I Allergy)

on first contact with allergen, specific B cells form IgE

**generally no signs or symptoms

Second exposure (provocative dose) Type I Allergy

causes the release of cytokines, producing a response

physiological effects and symptoms of a type I allergy

-vasodilation and bronchoconstriction (constriction of airway)

-rash, itching, redness, increased mucous, swelling, difficulty breathing

What do basophils produce during an allergic response?

histamine

What are common cytokines?

histamine and leukotrienes; these are often targeted for treatment of allergic reactions (antihistamines such as Benedryl, Claritin, etc.)

What is atopy/atopic disease?

atopy usually results in milder, seasonal allergies, but can be more bothersome and chronic like eczema or asthma

How are allergies treated and prevented?

1. Avoid allergen

2. Use drugs that block the action of the cells involved (antihistamines)

3. Desensitize therapy- allergy shots

Blood Type - A

antigen A, antibody B (anti-B)

Can receive A & O blood, can give to A & AB

Blood Type - B

Antigen-B; Antibody-Anti A;

Can receive from B or O; Can donate to B or AB

Blood Type - O

no antigens, anti-A and anti-B antibodies

universal donor

can receive from O; can donate to A, B, AB or O

Blood Type - AB

A and B antigens, no antibodies

universal recipient

can receive from A, B, AB or O; can donate to AB

Rh factor (D antigen)

additional marker that may be present in any type of blood

if present, then the person's blood is said to be Rh+

if not present, Rh-

Hemolytic Disease of the Newborn (HDN)

is caused by an Rh- mother having an Rh+ fetus and that usually the second pregnancy is affected and that Rh- mothers are given an injection of RhoGAM passive immunization to prevent rejection of the Rh+ fetus.

Lupus, Rheumatoid Arthritis, Rheumatic Fever & Serum sickness are why type of hypersensitivity?

Autoimmune (type III)

Autograft

transplantation of healthy tissue from one site to another site in the same individual

Isograft

transplant between identical twins

Allograft

transplantation of healthy tissue from one person to another person

Xenograft

a graft from individuals of another species (pig most common)

What are the 2 GENOTYPIC methods for identifying unknown microbes?

1. nucleic acid (DNA) probes

2. PCR (polymerase chain reaction)

What are the basis for immunological tests/reactions?

ANTIGENS reacting with ANTIBODIES (although, in some cases, antibodies react with other antibodies).

• extremely SPECIFIC.

Presumptive results

-allows you to presume what is causing the patient's infection, ex. Dipstick urinalysis test, Gram stain

Confirmatory results

-allows you to determine definitely what is causing the patient's infection, ex. Culture of urine

What does it mean to determine an antibody titer?

to determine the amount of antibodies a patient has