That bridge is looking quite appealing

What do T cells recognize when bound to a MHC protein?

Antigens

What type of protein do antigens bind to on the plasma membrane of cells that allow for T cells to recognize them?

Glycoproteins

What does MHC stand for?

major histocompatibility complex

What are the glycoproteins on the surface of plasma membranes produced by?

major histocompatibility complex (MHC) gene

Are the MHC proteins unique to each individual?

Yes; except for identical twins

What do MHC proteins bind to on the plasma membrane of body cells?

Antigens

What are the two major Classes of MHC proteins?

Class 1 MHC proteins & Class 2 MHC proteins

Where are Class 1 MHC proteins found?

The plasma membrane of all nucleated cells

Where are Class 1 MHC proteins not found?

Red blood cells

What is an antigen presenting cell?

They engulfing pathogens, digesting them into small peptides, and displaying these antigens on their surface via class 2 MHC proteins to activate T-lymphocytes

Where are class 2 MHC proteins found?

The plasma membrane of Antigen presenting cells (Dendrites, macrophages, B cells) and lymphocytes

What are the two main types of macrophages?

Fixed and floating

What are examples of structures that house antigen presenting cells?

lymph nodes and spleen

What determines what type of MHC protein a T cell can bind to?

Cluster of differentiation (CD) markers

What are the two Cluster of Differentiation (CD) Markers?

CD8 markers & CD4 markers

Where are CD8 markers found?

On Cytotoxic T cells and regulatory T cells

What type of MCH protein do CD8 markers respond to?

Class 1 MCH markers

What cells are CD4 markers found?

Helper T cells

What type of MHC protein do CD4 markers respond to?

Class 2 MHC proteins

What happens when T cells become activated by the MHC protein with an antigen they recognize?

They undergo mitosis producing identical clone cells

What are the types of T cells that have CD8 markers that are activated by class 1 MHC proteins and react quickly?

Cytotoxic T cells, and Memory T cells

What are the types of T cells that have CD8 markers that are activated by class 1 MHC proteins and react slowly?

Regulatory T cells

What do cytotoxic T cells attack and destroy?

Infected and abnormal cells displaying antigens

What type of T cells are highly mobile cells that roam throughout injured tissues?

Cytotoxic T cells

What are the three ways that Cytotoxic T cells attack and destroy infected and abnormal cells displaying antigen?

Perforins, cytokines, and lymphotoxin

What happens when cytotoxic T Cells release perforins?

forms pores on the plasma membrane of target cell

What happens when cytotoxic T Cells release cytokines?

activate genes for apoptosis (programed cell death)

What happens when cytotoxic T Cells release lymphotoxin?

Kills target cell

During the first exposure to an antigen how long is the response from a cytotoxic T Cell?

It takes a significant amount of time, 2 days to reach sufficient levels.

What is produced when T cells with CD8 markers are activated?

Memory T cells

What happens when a Memory T cell is re-exposed to an antigen?

They differentiate into cytotoxic T cells and produce a rapid and effective response

How do regulatory T cells moderate the response of other T cells and B cells?

By secreting inhibitory cytokines called suppression factors

What are cytokines?

signaling proteins released by immune cells

Why does the response of regulatory T cells take longer than the response of Cytotoxic T cells

Because they take longer to activate and their are fewer that are activated.

What do activated CD4 T Cells produce?

Active Helper T cells & Memory Helper T cells

What do the cytokines secreted by activated helper T cells do?

stimulate cell-mediated and antibody mediated immunity

(☆ ask slide 15 vs 16) What do the Cytokines of inactive Helper T cells do?

• Promote Activation of B cells

• Attract and stimulate Cytotoxic T Cells

• Attracts and stimulates macrophages

• Stimulates T cell division that produce memory T cells

• Speeds up the maturation of Cytotoxic T cells

How many different populations of B cells does the human body contain?

Millions

What do B cells carry?

thousands of unique antibody molecules bound to its plasma membrane

What happens to an antigen when its in the presents of its antibody on the plasma membrane of a B cell?

Binds to the B cell

How does a B cell become sensitized?

1) The inactive B cell has antigens attach to it’s antibodies

2) The antigens are brought into the B cell through endocytosis

3) The antigen binds to the Class 2 MHC protein and goes to the cell membrane.

4) A helper T cell can now activate it

What has to happen for a Helper T cell to activate a B cell?

The B cell has to be sensitized

How does a Helper T cell activate the sensitized B cell?

Helper T cells bind to the B cells class 2 MHC protein then secretes cytokines that promote B cell activation

What’s produced by an activated B cell?

Plasma and memory B cells

What does the activated B cell do to create plasma and memory B cells?

It divides several times producing daughter cells that differentiate into plasma cells and memory B cells

What do plasma cells do?

Plasma cells synthesize and secrete large quantities of antibodies

Which antigens can the antibodies produced by the plasma cells recognize?

same antigens as the antibodies on the plasma membrane of the activated B cell

How many antibodies can a plasma cell secrete hourly?

100 million antibody molecules

When is inflammation triggered?

From physical trauma, intense heat, irritating chemicals, or infection by viruses, fungi or bacteria.

What are the beneficial effects of inflammation?

Prevents spread of damaging agents, Disposes of cell debris and pathogens, Alerts adaptive immune system, and Sets stage for repair

What are the four major signs of acute inflammation?

Redness, heat, swelling, and pain

What causes the release of inflammatory chemicals?

Tissue injury & immune cells

What is a key component of the inflammatory response and releases histamine?

Mast cells

What is released by Mast cells that is of note during the inflammatory response?

Histamine

What are the inflammatory chemicals?

Histamine, Kinins (Bradykinin), prostaglandins, and complement proteins

What is the effect that inflammatory chemicals have on the body?

They dilate local arterioles, make local capillaries leakier, and attract leukocytes to the area

During the inflammatory response what is responsible for the redness and heat?

Vasodilation through increasing blood in the area

What does vasodilation cause in the inflammatory response?

Redness and heat

What is the fluid containing clotting factors and antibodies that leaks from the capillaries into the tissue?

Exudate

What is exudate?

The fluid containing clotting factors and antibodies that leaks from the capillaries into the tissue

What does Exudate during the inflammatory response cause?

produces swelling (edema) and pain through increased pressure on nerve endings

What is edema?

Swelling produced by exudate which puts excess pressure on nerve endings causing pain.

What is produced by bacterial toxins within the inflammatory response?

The release of prostaglandins and kinins which produce pain.

What does sensitization do during the inflammation response?

It lowers the pain threshold, amplifying pain, causing the release of prostaglandins and kinins

How does Aspirin and other anti-inflammatory drugs work?

They inhibit prostaglandins, which in turn reduces pain

How does exudate aid the immune response in tandem with the lymphatic system?

the surge of protein rich fluids in the tissue washes the foreign material into lymphatic vessels causing the lymphatic system to respond.

How do the contents of exudate aid the immune response?

It delivers important proteins to the area. Complement proteins, and clotting factors that isolate the injured area and prevents the spread of the foreign material.

What are the four steps that allow the mobilization of phagocytes to injured areas?

Leukocytosis, Margination, Diapedesis, & Chemotaxis

What is Leukocytosis?

First step of the mobilization of phagocytes to injured area. When leukocytosis inducing factors is released form damaged cells it induces neutrophils to enter blood from red bone marrow

What causes Leukocytosis?

leukocytosis inducing factors

What is Margination?

Second step of Mobilization of Phagocytes to Injured Area. Cell adhesion molecules on endothelial cells of inflamed tissue signal the site of injury. When the Cell adhesion molecules on neutrophils are activated by inflammatory chemicals they bind to the endothelial cells of capillaries

What is diapedesis?

Third step of Mobilization of Phagocytes to Injured Area. The neutrophils flatten and squeeze through the endothelial cells of the capillary wall.

What is Chemotaxis?

The last step of phagocytes moving to injured areas. Neutrophils and other WBCs migrate up gradient of chemotactic agents released during inflammation.

How long does it take for neutrophils to gather at a site of injury from the start of inflammation?

Within the hour

How do monocytes get to an injured area?

They follow the neutrophils

After a monocyte leaves the blood how long does it take for it to differentiate into a macrophage?

Within 12 hours

What type of protein enhances the innate response?

Antimicrobial Proteins

What are the two most important antimicrobial proteins?

Interferons and complement proteins

What produces interferons?

Cells infected by viruses

Whats the function of interferons?

They are released from the infected cell and bind to the receptors in near by cells. This binding stimulates the cell to produce antiviral proteins that block viral protein synthesis and degrade viral RNA

What do the proteins that are produced by interferons stimulating cell receptors do?

They interfere with the normal function of viruses by blocking protein synthesis, and degrading viral RNA

Are Interferons virus specific or non-specific

They are not virus specific

What is this?

The interferon’s function cycle

What are the three types of interferons?

Alpha (α), Beta (β), and Gamma (γ)

Whats the effect of an alpha interferon?

Has antiviral effects, and activates natural killer cells

What do beta interferons do?

Has antiviral effects, and activates natural killer cells

What are Gamma interferons secreted by?

T cells and NK cells

What do gamma interferons do?

Activates macrophages

How many different plasma proteins that circulate in blood are apart of the complement system?

Over 20

What proteins are included in the complement system?

C1-C9, Factors B, D and P, & Regulatory proteins

When the complement system is do to inflammation?

Enhances inflammation

What makes up the adaptive defense system?

T cells & B cells

What makes the adaptive defense system special?

It is specific, systemic, and has memory

What does it mean for the adaptive defense system to be specific?

It targets specific pathogens

What does it mean for the adaptive defense system to be systematic?

It is not restricted to initial infection site.

What does it mean for the adaptive defense system to have memory?

Mounts a faster and stronger defense against pathogens previously encountered.

What do the B cells do within the adaptive defense system?

Involved in the humoral antibody-mediated immunity. It’s Antibodies produced through humoral immunity circulate in blood and lymph
binding to extracellular pathogens

What do T cells do in the adaptive defense system?

They are involved with cell-mediated immunity and when activated T cells attack cells infected with pathogens directly

What are the four primary types of T Cells?

Cytotoxic, Helper, Regulatory, & Memory T Cells.

What do Cytotoxic T cells (T_c) do?

Directly attack antigen presenting cells