Immune System

By: Chas Pedersen

Self vs. Nonself

T cells- T cells go around the body reading each cells "bar code" which is made up of proteins unique to us and if they do not match the T cell will act upon this cell. Usually in most cases destroying the cell.

2 Types of Responses

Innate Immunity- nonspecific defense mechanisms that come into play immediately or within hours of an antigen's appearance in the body. These mechanisms include physical barriers such as skin, chemicals in the blood, and immune system cells that attack foreign cells in the body.

Humoral Immunity- is the aspect of immunity that is mediated by macromolecules (as opposed to cells) found in extracellular fluids such as secreted antibodies, complement proteins, and certain antimicrobial peptides.

Roles of Immune Cells

White blood cells, also called leukocytes or leucocytes, are the cells of the immune system that are involved in protecting the body against both infectious disease and foreign invaders. All white blood cells are produced and derived from a multipotent cell in the bone marrow known as a hematopoietic stem cell.

Difference Between Active and Passive Immunity


  1. Produced due to contact with pathogen or antigen
  2. Immunity is not immediate it takes a while
  3. The immunity lasts a long time and even a life time
  4. Very few side effects


  1. Produced due to antibodies obtained from outside
  2. Immunity is immediate
  3. Does not last very long
  4. Has some side effects that can get you sick

How Do Vaccines Fit Into Immunity

When the Vaccine is injected into he body a weakened form of the virus is presented to the T cells. The T cells nit knowing that it is a weakened form of the virus attacks it as if it were a dangerous virus. This process produced an antibody for the body so that if a virus for the vaccine were to be in the body the T cells can destroy it.