Immunology: Specific Defenses

40-2 Continues….

SPECIFIC DEFENSE: 3rd Line If the 1st (skin) and 2nd (Inflammatory

Response) lines of defense don’t work, an Immune Response is started Pathogens are coated with antigens 2 types of Immune cells (WBC’s) recognize

pathogens B cells: fight pathogens/antigens in body fluids T cells: fight abnormal cells and pathogens inside living

cells

B Cells Attack!!!!

When a pathogen enters the body:1. B cells recognize the antigens and divide

rapidly (Think the size of an army)2. Many B cells produce antibodies (proteins that

bind to antigens; these markers tell the body where the “bad guys” are)

3. Other B cells turn into memory cells. If the pathogen attacks the body a second time; these cells divide rapidly and produce mass amounts of antibodies

Antibodies

These proteins are “Y” shaped in structure

Each branch of the “Y” can bind to an antigen

Antibodies are specific for antigens Similar to the lock and

key model Healthy adults can produce

about 100 million different types of antibodies!

T Cells Attack!!!!!

Once the antibodies are attached to the pathogens, Natural Killer T cells destroy the pathogen

Other T cells may help activate Killer T cells or Memory T cells (which act the same way as Memory B Cells)

Killer T cells kill pathogens found inside other cells as well as body cells gone bad

Passive vs. Acquired Immunity Passive Immunity:

Any time Antibodies are injected or introduced into an organism, it is passive immunity.

The immunity is given to the organism without any work being done

Acquired Immunity Requires the organism to

make Antibodies Can be the result of

previous infection Often the result of

Vaccination Vaccines are weakened

or dead versions of a live more harmful pathogen

Immune system goes wrong…. Allergies: Overreactions of the immune system…normally the

body is trying to kill something that is not harmful The body produces Histamines which cause sneezing, itchy

eyes, running nose etc… Treatments include antihistamines

Asthma: A severe respiratory allergic response in which the airways become inflamed There is not cure but many treatments including steroids

Autoimmune Disorders: Sometimes the body doesn’t recognize its own cells and attacks them. Examples include: Rheumatoid arthritis, Multiple Sclerosis,

AIDS and Type I Diabetes