By: Alisa Fay, Rachel Robert, Lindsay Kilday & Kirsten Meisterling.

By: Alisa Fay, Rachel Robert, Lindsay Kilday & Kirsten

Meisterling

Stem Cell

Lymphoid Stem Cell Myeloid Progenitor

B Cell T Cell Natural Killer

Neutrophil Eosinophil Monocytes

Basophil Mast Cell

Plasma Cell

Plasma Cell

Mast Cell

Cytotoxic Helper Suppressor

Immune System “Players”: Major Cells

• Stem Cell: an undifferentiated cell whose daughter cells may differentiate into two different cells

• Lymphoid Stem Cell: white blood cell (WBC) of the immune system that is part of the lymph system

• Myeloid Progenitor: makes platelets, red blood cells and some WBCs

Immune System “Players”: Lymphoid Cells

• B Cells: A lymphocyte that matures in the bone marrow and carries out humoral immune response. B Cells have membrane bound antigen receptors.– Plasma Cell: (Activated by B Cells) Secrete

antibodies to eliminate certain antigens– Memory Cell: (Activated by B Cells) Remember

antigen that caused its formation

Plasma CellThe orange part is the endoplasmic reticulum that manufactures, modifies and transports proteins, or antibodies. The cells nucleus is redish-brown and the

dark brown dots are mitochondria which provide the cell with energy.


• T Cells: A lymphocyte that matures in the thymus and functions in cell mediated response.– TC (Cytotoxic) Cells: Kill infected cells and cancer cells– TH (Helper) Cells: Secrete Cytokines, molecules that

are released by one cell as a regulator of a neighboring cell ( B and T cells)

– TS(Suppressor) Cells: Probably turn off immune system when antigen is gone.

• Memory T Cells: Cells that fight certain previously exposed infections faster and stronger than the first time.

T Cell in ActionCytotoxic T Cell (orange) killing a cancer cell (purple).


• Natural Killer Cells (NK Cells): Cells that destroy a body’s infected cells, especially the ones that harbor viruses, and aberrant cells, which can form tumors.– “Shake hands” with cell– If cell has no recognizable MHC

(identification), then the NK kills it

– Attack the membrane of target cell causing it to lysis

Immune System “Players”: Myeloid Progenitor Cells

• Phagocyte Cells: WBCs that ingest invading particles– Eosinophils

• 1.5% WBCs• Limited phagocytic activity, but contain enzymes within

cytoplasmic granules• Destroy parasites by positioning themselves on walls and

releasing enzymes– Neotrophils

• 60-70% of WBCs• Can leave blood and enter infected tissues to destroy

microbes, then self destruct• Live only a few days

Eosinophil:Above showing the granules

which release enzymes and the size. To the right showing a

eosinophil attacking a parasite.

Parasite

Neutophil: Leaving the blood to migrate into a tissue and a Neutrophil animation


• Monocytes– 5% WBCs– Very effective phagocytic defense– Monocytes develop into macrophages (big eaters) after

migrating into a tissue– Have amoeboid cells that pull in microbes which are then

destroyed (by enzymes and reactive oxygen) with macrophages

– Some macrophages reside permanently in organs and connective tissue (many reside in lymph nodes and the spleen)

– Macrophages secrete hormones called cytokines that call for immune system cells and activate cells involved in tissue repair


• Basophils and Mast Cells– Contain the chemical histamine which aids in the

inflammatory response– When these cells are injured in connective tissue,

histamine is released– This triggers vasodilation and makes the capillaries

“leaky”

Vasodilation by histamines released

by basophils and mast cells

Monocyte ready to defend against

antigens

Substances

Body tissue Body tissue

Alfha, beta, gammaAlfha, beta, gamma

Substances

contained in basophils and mast cellscontained in basophils and mast cells

Chemical signalChemical signalThis can be used as a biochemical fingerprint to each individual.

This can be used as a biochemical fingerprint to each individual.

Substances

Helps cause local vessel dilation.Helps cause local vessel dilation.

Blood clotting Blood clotting

Substances

Molecule that sets the body’s thermostat at a higher temperature.

Molecule that sets the body’s thermostat at a higher temperature.

Specific protein produced by specialized lymphocytes.

Specific protein produced by specialized lymphocytes.

Process: Fighting an Infection

1. Chemotaxis

• When the epithelium of the skin is damaged, chemicals are sent into the bloodstream by the invading bacteria and tissues – These molecules, called chemokines, attract phagocytic

cells to the infected area

•Chemotaxis is the process of phagocytic cells migrating to the source of the chemical attractant

2. Vasodilation

• When the chemokines are released, vasodilation, the widening of the arteries, also occurs – Increases the blood flow to the infected area, carrying

the needed white blood cells – Causes the redness and heat as the white blood cells

work to cure the infection

Inflammation:Inflammation:

1.redness 2.pain 3.swelling4.heat

3. Diapedesis• When the white blood

cells get to the infected area in the bloodstream, they undergo the process of diapedesis

• The cells move through the epithelium of the capillaries and into the surrounding interstitial fluid to destroy the invaders

3. Diapedesis• When the white blood cells get to the infected area in the bloodstream, they undergo the process of diapedesis

• The cells move through the epithelium of the capillaries and into the surrounding interstitial fluid to destroy the invaders

1. damaged cell releases chemokines

1. damaged cell releases chemokines

2. chemokines sensed by neutrophils/monocytes2. chemokines sensed by neutrophils/monocytes

3. monocytes squeeze out of capillaries (diapedesis)

3. monocytes squeeze out of capillaries (diapedesis)

4. monocytes (and/or macrophages) start to engulf pathogen(phagocytosis)

4. monocytes (and/or macrophages) start to engulf pathogen(phagocytosis)

4. Phagocytosis

• When the phagocytic cells get to the invaders, they go through the process of phagocytosis to finally eliminate the bacteria

4. Phagocytosis• When the

phagocytic cells get to the invaders, they go through the process of phagocytosis to finally eliminate the bacteria

• The Pseudopodia on the macrophages attach to polysaccharides on the microbes surface to pull it in.

• Once the microbe is in the cell, the lysosome comes to destroy it

• The lysosome in the cell can kill the microbe in one of two ways:

1) Generating toxic forms of oxygen 2) Releasing enzymes that digest microbial components

Clotting Cascade

• When the skin’s epithelium is damaged, a series of reactions occur to stop the bleeding

• The cascade follows two pathways: extrinsic and intrinsic and then finishes in the final common pathway

http://www.hopkinsmedicine.org/hematology/Coagulation.swf

Edema-Definition: large amount of fluid beneath the skin; swelling

-Homeostasis maintains the amount of interstitial fluid around the body

- Too much fluid causes swelling as well as poor removal of fluid

How it starts-- Leaky Capillaries

Two types of pressure measured in the capillaries:- hydrostatic pressure: causes water to filter into

surrounding tissues- oncotic pressure: pulls water back into the vessel

from the tissuesTogether the two pressures maintain homeostasis of fluid

levels in the body

Most leakage occurs in the capillaries due to there semi-permeable membrane

Factors that increase leakage of fluid1. increase of hydrostatic pressure in vessel2. decrease of oncotic pressure in vessel3. increase in vessel wall permeability

Humoral Immunity

What is it?

Transformation of B-cells into plasma cells that can then produce and secrete antibodies

B-cells =

-created in the bone marrow

-circulate through blood and lymph

-changes into a clone of plasma cells to secret a specific antibody

-also can change into a clone of memory cells to make antibodies after first encounters

1st Antigen Exposure-Antigen is engulfed by macrophage

-Macrophage stimulates Helper T-Cell

-Helper T-Cells stimulate B-Cells and Cytotoxic T-Cells

-B-Cells turn into plasma and memory cells

-Plasma cells secret antibodies into blood; memory b-cells are “stored” until their specific antigen shows up again (2nd exposure)

-Cytotoxic t-cells turn into active cytotoxic t-cells and memory t-cells

- Cytotoxic t-cells go and kill the antigen; memory t-cells are also stored until their specific antigen shows up again (2nd exposure)

Cellular ImmunityWhat is it?

Ability for antibodies to recognize a foreign organism, known as antigens, and destroy it

Advantage

Allows for a person’s body to destroy of antigen faster before the antigen, which could be harmful to a person, causes damage

Types of WBC’s (antibodies)

Cellular vs. Humoral Immunity

-Humoral immunity is the first stage the builds the memory b-cells for cellular immunity.

-Cellular immunity depends on the cells that are made during b-cell and cytotoxic t-cell transformation into memory cells

-Memory cells are formed with specific antibody receptors that bind to a specific antigen

Clonal SelectionDefinition

-The selection of a lymphocyte by an antigen which activates the lymphocyte stimulating it to divide and diferentiate.

Two Types:

1. Effector cells

--plasma cells--make antibodies--short lived

2. Memory cells

--long lived

White blood cells fighting a antigen

the antibody (Ab) proteinhypervariable region (hundreds of billions of possible shapes)

constant region (same for all antibody molecules)(aka Fc region)

a simpler way to show the antibody molecule

hypervariable region (hundreds of billions of possible shapes)

constant region (same for all antibody molecules)(also called Fc region)

•Ab are incredibly SPECIFIC•each one will bind ONLY to its matching antigen.•this shows 14 different antibody molecules. •in reality there would be MANY BILLIONS of different antibodies.

antigens (Ag)•any foreign object that our immune system can react with•protein, virus, bacterial cell, toxic molecule, pollen grain, polysaccharide, etc•here, there are 8 shown•in reality there are hundreds of billions•any ONE bacterial cell might have hundreds or thousands of antigenic proteins on its surface

•Antigens and Antibodies must make an EXACT MATCH•if they don’t match – no triggering, no sticking•if they DO match – they stick together strongly•if they DO match – triggers something to happen

•what DOES happen when they match?

http://www.nwfsc.noaa.gov/hab/habs_toxins/marine_biotoxins/detection/elisa.html

another way to show the antibody molecule...

B cell

• B cells make antibodies• each B cell makes ONE

type of antibody• but it makes a lot of

them• it sticks those Ab on its

surface, with the “red” end facing out• if any “red” antigen

comes around, it will be “caught” by the surface Ab

B cell

• if any “red” antigen comes around, it will be “caught” by the surface Ab• NO OTHER antigen will

be caught• this “primes” the B cell

• B cell matures into plasma cell• plasma cell pumps out

its specific antibody• plasma cell also

replicates• all daughter cells also

pump out “red” antibody

• plasma cell also replicates• all daughter cells also pump

out “red” antibody

B cell

this is a B cell which produces “red” Ab

here’s an even simpler diagram showing a B cell with “red” antibodies

recall there would be millions of different B cells circulating

each would have its own Ab projecting from its surface

Lymphocytes-White blood cells-Built with specific, unique antibodies on their surface-Antibodies are proteins that bind with antigens to neutralize itBecause of cellular immunity, the body knows which white blood

cell carries the specific antibody to “battle” the antigenAdvantage:

having the specific antibody that neutralizes the antigen is helpful because the antibody can “battle” and destroy antigens quickly and easily

WBC vs. RBC

In the first line of Defense the immune system remains non-specific. Elements of the immune system active at this point:

• Mucous•Skin •Secretions (skin & mucous membranes)

Second Lind of Defense-It still remains non-specific, as the natural response occur. • Inflammatory Response (w/histamine)•Phagocytic WBC’s (ingestion of invading cells)•Neutrophils are attracted to damaged cells•Monocytes release macrophages•Natural killer cells are released •Antomicrobial Proteins complement the system and directly attack microbes or impede reproduction

Third Line of Defense is where the immune system is specific. Lymphocytes come into play:

B Lympho’sT Lympho’s __ membrane bound antigen receptors

Also Antigens, which are antibody generator At this point there is clonol selection where the selection of a lymphocyte by an antigen activates the lymphocyte stimulating it to divide and differentiate.

There are memory cells, which are created after antigen receptors and antigen molecules (B cells) and this end up

being antibody molecules. These consist of memory cells and plasma cells.

The memory cells make it possible for the body to recognize viruses that have already entered the body once before.

The main function of the immune system is distinguishing self from non-self. The essence of immunological response is a two part system: recognition and

destruction. The pathogens or foreign bodies that trigger the immune system are called antigens. Antibodies is the structure which mostly recognizes foreign

bodies. They go throughout the body “shaking hands” with the other cells to make sure they know each other and to see if anything is wrong with the cells of the

body.

In the immune system there must be a diverse amount of lymphocyte receptors to ensure that at least a few lymphocytes can bind to any given pathogen. This diversity

is created from inherited gene segments or libraries.

Memory cell

The subjects in the box are what occurs as a second sighting of the antigen.

By: Alisa Fay, Rachel Robert, Lindsay Kilday & Kirsten Meisterling.

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Transcript of By: Alisa Fay, Rachel Robert, Lindsay Kilday & Kirsten Meisterling.