Week 7 HUBS1406 - Immune system

3 lines of Immune system defence – primary, secondary and tertiary [blank_start]Primary[blank_end] – skin, hair, nasty substances mucosal membranes, sweat, cilia, HCl [blank_start]Secondary[blank_end] – Phagocytic white cells, inflammation, chemical weapons and turning up the heat [blank_start]Tertiary[blank_end] - Lymphocytes, antibodies, memory cells

Neutrophils are a type of white blood cell (WBC or granulocyte) that protect us from infections, among other functions. They make up approximately 40 percent to 60 percent of the white blood cells in our bodies, and are the first cells to arrive on the scene when we experience a bacterial infection.

[blank_start]Neutrophils[blank_end] are a type of white blood cell (WBC or granulocyte) that protect us from infections, among other functions. They make up approximately 40 percent to 60 percent of the white blood cells in our bodies, and are the first cells to arrive on the scene when we experience a bacterial infection. [blank_start]Monocytes[blank_end] are the biggest type of white blood cell in the immune system. Originally formed in the bone marrow, they are released into our blood and tissues. When certain germs enter the body, they quickly rush to the site for attack.

Monocytes are the biggest type of white blood cell in the immune system. Originally formed in the bone marrow, they are released into our blood and tissues. When certain germs enter the body, they quickly rush to the site for attack.

INFLAMMATION The inflammatory response (inflammation) occurs when tissues are injured by bacteria, trauma, toxins, heat, or any other cause. The damaged cells release chemicals including histamine, bradykinin, and prostaglandins. These chemicals cause blood vessels to leak fluid into the tissues, causing swelling. This helps isolate the foreign substance from further contact with body tissues. The chemicals also attract white blood cells called phagocytes that "eat" germs and dead or damaged cells. This process is called phagocytosis. Phagocytes eventually die. Pus is formed from a collection of dead tissue, dead bacteria, and live and dead phagocytes.

Mast cells are long-lived tissue-resident cells with an important role in many inflammatory settings including host defence to parasitic infection and in allergic reactions. Mast cells are located at the boundaries between tissues and the external environment, for example, at mucosal surfaces of the gut and lungs, in the skin and around blood vessels. Mast cells are key players in the inflammatory response as they can be activated to release a wide variety of inflammatory mediators, by many different antigens including allergens, pathogens and physiological mediators.

What are the five cardinal signs of inflammation?

Interferons (IFNs) are a group of signaling proteins made and released by host cells in response to the presence of several viruses. In a typical scenario, a virus-infected cell will release interferons causing nearby cells to heighten their anti-viral defenses

A fever is a prevention technique for the body to prevent the bacteria from replicating

Two type of defence of the immune system:

Antigen - a toxin or other foreign substance which induces an immune response in the body, especially the production of antibodies.

With the help of T-cells, [blank_start]B-cells[blank_end] make special [blank_start]Y-shaped proteins[blank_end] called [blank_start]antibodies[blank_end]. Antibodies stick to [blank_start]antigens[blank_end] on the surface of germs, stopping them in their tracks, creating clumps that alert your body to the presence of intruders. Your body then starts to make toxic substances to fight them. Patrolling defender cells called [blank_start]phagocytes[blank_end] engulf and destroy [blank_start]antibody-covered[blank_end] intruders

The basic structural unit of an antibody molecule consists of four polypeptide chains

The basic structural unit of an antibody molecule consists of three polypeptide chains

Immunoglobulins, also known as antibodies, are glycoprotein molecules produced by plasma cells (white blood cells). They act as a critical part of the immune response by specifically recognizing and binding to particular antigens, such as bacteria or viruses, and aiding in their destruction.

The various antibodies produced by plasma cells are classified by isotype.

The various antibodies produced by plasma cells are classified by protein type.

Five major antibody classes have been identified in placental mammals: IgA, IgD, IgE, IgG and IgM.

[blank_start]Immunoglobulin A (IgA),[blank_end] which is found in high concentrations in the mucous membranes, particularly those lining the respiratory passages and gastrointestinal tract, as well as in breast milk, saliva and tears. [blank_start]Immunoglobulin G (IgG),[blank_end] the most abundant type of antibody, is found in all body fluids and protects against bacterial and viral infections. Also crosses the placenta. [blank_start]Immunoglobulin M (IgM),[blank_end] which is found mainly in the blood and lymph fluid, is the first antibody to be made by the body to fight a new infection. [blank_start]Immunoglobulin E (IgE),[blank_end] which is associated mainly with allergic reactions (when the immune system overreacts to environmental antigens such as pollen or pet dander). It is found in the lungs, skin, and mucous membranes. [blank_start]Immunoglobulin D (IgD),[blank_end] which exists in small amounts in the blood, is the least understood antibody.

Passive immunity is an immune response which involves antibodies obtained from outside the body. An example of this is the antibodies a mother passes to her infant through her breastmilk.

Naturally acquired passive immunity – IgG through the plasma during pregnancy.