• non-specific
• We are born with it
• Skin and mucous membranes make up the first line of defense.
• Phagocytes make up the second line of defense

• Third line of defense
• Specific to various pathogens that attack the body
• Takes longer to develop but is very effective
• Works along with the adaptive system

Humoral Immunity (Anti-body mediated)

Cellular Immunity (Cell mediated)

Antibodies are releasesd to the blood and lymph.

Antibodies are proteins that combine with bacteria or viruses and inactivate them or help get rid of them

Involves B cells

• Activated cells fight against infected cells, cancer cells, and transplanted cells
• Involves T cells

mostly foreign substances but also cancer cells. 

the are the target of all adaptive immune responses.

All lymphocytes are formed in the bone marrow.

B lymphocytes stay in the bone marrow to develop immunocompetence

T cells move to the Thymus to develop immunocometence

All B and T cells are considered "naive" until they come into contact with a pathogen.

It means they acquire a specific antigen receptor.

Once they recieve antigen receptors they are dispersed to the secondary lymphoid organs such as lymph nodes and the spleen.

What is clonal selection theory and the Humoral Immune response?

• Antigen combines with a B cell that has a receptor complimentary to it.
• The cell clones itself into:
• Plasma cells: secrete large amounts of antibodies that can combine with the antigen
• Memory cells: mount an almost immediate humoral response if they encounter the same antigen again
• secondary exposure responses happen much faster and with more antibody production

• Vaccines are weakened (attenuated) viruses or bacteria that stimulate the immune system but aren't strong enough to give you the disease
• Therefore when you really do come into contact with the bacterium or virus your body ilicits a secondary response and you do not get sick.

• helper T cells
• cytoxic T cells

• central to the adaptive immune response because they stimulate B and T cells to proliferate by secreting Inter-Leukins

**HIV, the AIDS virus, destroys this cell type and so destroys a persons immune system.

• Cytoxic T-cell joins with the infected cell and releases the contents of its granules.
• Granule contents: 
• Perforin: Makes holes on the surface of target cell
• Granzymes: proteolytic enzymes which enter through the holes and start destruction of the cell.
• Cell will then kill itself: Apoptosis