Innate Immune System

• Made of defenses against infection that can be activated immediately once a pathogen attacks
• Essentially is a bunch of barriers that work to keep viruses, bacteria, parasites, and other foreign particles out of the body
• Also works to limit their ability to move and spread throughout the body

Innate Immune System

• Physical barriers: skin, gastrointestinal tract, respiratory tract, nasopharynx, cilia, eyelashes and other body hair
• Defense mechanisms: secretions, mucus, bile, stomach acid, saliva, tears, and sweat
• Common immune responses: inflammation, complement, and non-specific cellular responses.

Innate Immune System

• Types of white blood cells in the innate immune system: phagocytes, macrophages, mast cells, neutrophils, eosinophils, basophils, natural killer cells, and dendrite cells
• Complement system works with the innate immune system, but if needed, it can work with the adaptive immune system.

Innate Immune System

• The complement system: made of many proteins that, when activated, circulate in the blood
• When the complement system is activated, the proteins come together to start the complement cascade which has 4 steps

Innate Immune System

• 4 steps of the complement cascade:
• Opsonization: foreign particles are marked for phagocytosis
• Chemotaxis: the attraction and movement of macrophages to a chemical signal
• Cell Lysis: the breaking down or destruction of the membrane of a cell
• Agglutination: uses antibodies to cluster and bind pathogens together so then the immune system can attack and weaken the infection

B lymphocytes

• They clean up after the T lymphocytes have attacked the virus
• Make antibodies
• Our bodies have 10 billion different B cells
• If lined up they can be as long as 100 soccer fields

B lymphocytes

• They have receptors that connect to antigens
• B cells that recognize self-antigens are demolished
• They can connect to antigens on the surface
• They can also attack viruses/bacteria outside the cell

B lymphocytes

• Helper T cells send chemicals that tell B cells to multiply several times
• Several B cells turn into plasma cells
• Plasma cells function like the B cells like making antibodies and connecting to antigens
• Plasma cells can make thousands of antibodies per second

B lymphocytes

• They are made in the bone marrow
• Then they leave the bone marrow and mature in the thymus
• Lymphokines is secreted which stimulates the B cells to enter the cell cycle and repeat mitosis

Untitled Slide

Untitled Slide

Untitled Slide

Untitled Slide