Immunity Q and A

What is the name of our immunity response that involves the first and second line of defense?

(Nonspecific) Innate immunity, which we have from birth, forms the first and second line of defense.

What is the name of our immunity response that involves the third line of defense?

(Specific) Adaptive immunity, which we acquire over the course of our lifetimes, is the third line of defense.

What does increased permeability do to the injured tissue and what stage is it associated with?

Increased permeability is associated with the first stage, vasodilation. It allows defensive immune substances to get out of the blood and travel to the site of inflammation. These substances include antibodies and clotting factors. This increased permeability also allows toxins and dead cells to be removed from the site.

What is an interferon and how does it slow the spread of viral infections?

Interferon is a chemical release by cells that have been infected by a virus. It signals nearby cells to produce antiviral proteins, granting them temporary resistance to infection in order to stop the virus from spreading to new host cells.

No, seriously...what does histamine do?

It causes dilation and increased permeability of blood vessels. Often as part of an inflammation response.

How do natural killer cells cause death to abnormal cells?

Natural Killer cells attach themselves to abnormal cells and release Perforin, which puts holes in the cells' cytoplasm leading to cytolysis and Granzymes which program the cell to destroy itself

What happens to helper T-cells once they spot an antigen specific for them?

Once a T-cell recognizes its specific antigen it secretes cytokines and undergoes mitosis to split into more T-cells.

What is different about scar tissue compared to normal tissue?

Scar tissue typically has dense collagen fibers, decreased elasticity and fewer blood vessels when compared to normal tissue.

What are the phases of inflammation?

The 3 stages are vasodilation, emigration of phagocytes and tissue repair.

What is a complement system and how does it stop microbe invaders?

The compliment system is a non-specific set of 30 proteins produced by the liver. Some of the proteins come together to form MAC's. Others work to enhance chemotaxis and the release of histamine.

What 3 events are triggered by the helpers release of cytokines?

The cytokines initiate and control the immune response by stimulating B-cells to produce antibodies, regulating T-cell cytotoxic activity and encouraging the formation of more macrophages.

Which phagocyte is the main antigen presenting cell?

The dendritic cells. They process antigens and present them for the T-cells, acting as messengers between the innate and adaptive immune systems.

List and describe each component of the first line of defense.

The first line of defense involves physical barriers between the body interior and the outside world. These include: Our skin, which microbes cannot normally pass through, our mucus membranes which trap foreign substances trying to get in, hair and cilia which catch and sweep away invaders and digestive enzymes in the mouth and acid in the stomach, which break down potentially harmful pathogens that enter the upper digestive tract.

Which phagocyte is an example of microglia?

The fixed macrophages which come from monocytes. These can also function as antigen presenting cells.

For cell-mediated immunity, list the major players and their function.

The major players are the T-cells. Helper T-cells initiate and oversee the immune response, cytotoxic T-cells directly kill specific infected cells, Regulatory T-cells turn off the immune response once the job is done and Memory T-Cells roam through the body looking for antigens they have previously encountered.

For antibody-mediated immunity, list the major players and their function.

The major players are: B-cells which are activated in the spleen, lymphoid nodule, or lymph node to defend against antigens and pathogens, plasma cells which produce and secrete antibodies into interstitial fluid and Memory B cells which remember antigens so that if they show up again the body can attack them faster.

Which phagocyte is the first responder?

The neutrophils are always first on the scene when an immune response is needed. They are the most numerous phagocyte in the body and they work to destroy unwanted substances.

What makes up the second line of defense?

The second line of defense works on the interior of the body. It consists of: fever to overheat and kill pathogens, inflammation to raise blood flow and bring helpful immune cells and substances to injured or distressed areas, phagocytes and natural killer cells to destroy and consume pathogens and antimicrobial substances to inhibit the reproduction of anything that gets past them.

What makes up the third line of defense?

The third line of defense is specific and adaptive. It consists of Lymphocytes, antibodies and memory cells.

What are the distinct signs and symptoms of inflammation?

There are 4 distinct signs and symptoms. Redness, heat, pain and swelling.

Are natural killer cells specific or non-specific?

They are non-specific.

When would the second line of defense be activated?

When the first line (physical barriers) is breached and foreign substances or pathogens find a way to enter the body.

When is tissue repair considered done?

When the invading microbes have been removed from the site of injury.

What are the phases of phagocytosis?

1. chemotaxis: The chemical attraction of phagocytes, causing them to move toward a target. 2. adherence: Attachment of the phagocyte to the target. 3. ingestion: The phagocyte uses pseudo pods to engulf the target and place it in an endocytic vesicle called a phagosome 4. digestion: Lysosomes within the phagocyte release digestive enzymes into the vesicle containing the target which begin to chemically break it down. 5. killing: The target dies, its chemical energy is harvested by the cell

What is a MAC?

A Membrane Attack Complex, formed by proteins from the compliment system, is a donut like structure which embeds itself in the plasma membrane of pathogens, opening them up to osmotic influx of water, which causes them to swell and burst.

What is the difference between an antigen and an antibody?

An antigen is a protein on a cells surface which causes the immune system to produce antibodies. Antibodies are y-shaped molecules that recognize specific antigens and bind with them, "marking" the cells they are a part of as targets for immune system attack.

What happens to B-cells once they are activated?

B-cells undergo mitosis and turn into either plasma cells or Memory B-cells.

What is chemotaxis, what causes it,and what stage is it associated with?

Chemotaxis is a chemical signal released by macrophages that draws phagocytes to the area of inflammation. It is associated with the second stage.

What molecule triggers the helper T cell to present antigens to a B cell?

Cytokines.

What does histamine do?

Damn bro, what doesn't histamine do?

What is diapedesis and what stage is it associated with?

Diapedesis is the movement of blood cells through the capillary walls to sites of inflammation. It is associated with the second stage, emigration of phagocytes.

What causes inflammation?

Direct physical damage, caustic chemicals, ischemia or infarction, allergic reactions, extremes of heat or cold, foreign bodies. (Freakin' EVERYTHING)

How are cytotoxic T cells activated?

Either by a helper T-cell or an antigen presenting cell.

How is adaptive immunity acquired?

Either naturally through infection or maternal antibodies OR artificially through vaccination or monoclonal antibodies in blood transfusions.