Immune System
There are many types of protein immune system uses to fight off invaders:
"Interferons are proteins produced by body cells that are infected by a virus" (Nowicki 947) [Ben]. They stimulate healthy cells to create enzymes that prevent viruses from infecting them (Nowicki 947) [Ben].

There are 2 types of immunity: passive and active
Passive immunity occurs without body's immune response. They can be transferred between generations through DNA. Also passive immunity can mean that different species are automatically immuned to pathogens that aren't specialized to infect them (Nowicki 948) [Ben].
Active immunity occurs with body's immune response. Acquired immunity is a type of active immunity. It keeps you from getting infected by the same pathogens more than once (Nowicki 948) [Ben].
For more information about immunities, click here [Ben]

"Humoral immunity is a type of immune response that depends on antibodies" (Nowicki 953) [Ben]. It can cause the pathogens to burst, inactivated, or causing them to clump. First the pathogen binds to a B cell. Then the antigen is put onto the B cell's surface. A T cell then binds to the antigen part on a B cell, stimulating it to divide and differentiates into memory and activated B cells. Those activated B cells produce antibodies that cause the pathogens to clump, then phagocytes come and eat them, while memory B cells act as back ups (Nowicki 953) [Ben].

blue_pathogen_photo.JPG Pathogen [Polly] B-cell-picture1.jpg B cell [Polly]
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Sometimes, when a person is getting an organ transplant, tissue rejection can happen. It is when the body detects the foreign cells, and sends white blood cells to attack and eliminate it (Nowicki 954) [Ben]. When a cell's protein markers fit into the white blood cell's receptor, they are considered foreign. "Other times, the immune system loses the ability to recognize the body's healthy cells", thus "the immune system attacks the healthy body cells" (Nowicki 954) [Ben].
For more information about types of white blood cells, click here [Ben]
T cells function is: if the invader gets inside a cell, these (T cells) lock on to the infected cell, multiply and destroy it. (Nowicki 946) [Polly]
t-cell.gifT cell ( [Polly]

A bacteria and a virus share differences and similarities. A bacteria is a prokaryote and alive, while the virus is not a living thing, but both can harm whoever got infected by them. Since they are different, there are white blood cells that are specially for fighting them. When defending against bacteria, a type of white blood cell called eosinophil comes and sprays poison onto the pathogens (Nowicki 946) [Ben]. When defending against viruses, phagocytes come and engulf pathogens and destroy them (Nowicki 946) [Ben].
bacteria_cell.jpgBacteria ( [Ben]1211626994_virus.jpgVirus ( [Ben]

Vaccines are created to keep a person from getting a specific infection, not curing it. "Vaccination allows a person to develop memory cells and acquired immunity against and illness without actually contracting the disease" (Nowicki 956) [Ben]. They work faster than humoral immune response. they usually already contain pathogens' antigens, which causes an immune
response and creates memory B cells, which are ready when the real pathogens come, thus they can make antibodies faster (Nowicki 956) [Ben].
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HIV is a deadly infection. In fact, it is uncurable and so far there are no vaccine or medication that can cure it. HIV kills T cells. Because T cells tell activated B cells to make antibodies, when they die activated B cells can't make antibodies, thus making the body vulnerable to diseases and AIDS (Nowicki 961) [Ben]. But why is it uncurable may we ask? HIV kills T cells and reproduce faster than we reproduce T cells. If less T cells are available, they can't make activated B cells to create enough antibodies to fight against HIV (Nowicki 961) [Ben].
T4andHIV.jpgThousands of HIV on a T cell ( [Ben]

Antibodies are:

- A blood protein produced in response to and counteracting a specific antigen.

- Antibodies combine chemically with substances that the body recognizes as alien, such as bacteria, viruses, and foreign substances in the blood (Nowicki 947) [Polly]

antibodies.jpg Antibodies <> [Polly]

Antibodies destroyed pathogens. Antibodies might make the pathogen ineffective by binding to the pathogen’s membrane proteins. Antibodies might also cause pathogens to clump, making them easier for phagocytes to engulf and destroy. Other antibodies activate complement proteins that weaken the pathogen’s cell membrane. (Nowicki 947) [Polly]
biwhitebloodcell_(1).jpg Antibodies destroy pathogens <> [Polly]

As we know, inflammation and fever have the relationship with the immune system very much for preventing the viruses. Inflammation release chemical called histamines in response to a pathogen invasion, histamines cause the cells in blood vessels walls to spread out. When this happen, fluids can move out of the blood vessels and into the surrounding tissues (Immune system) Besides, Low fever - when the body is around 37.7 degrees - will support the protein to prevent the viruses (Immune system). The fever also increases the white blood cells, and white blood cells have a role of destroying viruses, so more white blood cells more destroying viruses (Immune system). White blood cell has the role of recognizing which are body cells or pathogens (foreign cells) (Immune system). White blood cell can recognize by the antigen, which body cells have it but pathogens (Immune system). There are 2 types of white blood cell: T cells which is functioning in cellular immunity, and B cells which is produce antibodies in humoral immunity (Immune system). White blood cells sometimes cause tissue rejection after an organ or tissue transplant because there is a something call protein maker, that rejects the attacks on donated tissues, because the protein maker have ability to recognize foreign tissues (Immune system).
Almost people take the bacteria as viruses but the fact is not. They both are microscopic and both can cause diseases or sickness. But the difference that viruses are considered as a living and non- living thing. And the viruses reproduce, duplicate themselves. Bacteria are alive. And they reproduce by splitting themselves into half and then make new bacteria (Immune system).

external image immune-system.jpg

Economy, Weak. "Researchers Discover New Way to Boost the Immune System | TopNews." TopNews | Only Top Stories of the Day. Web. 25 May 2011.

For more information about immune system, click here