PHYSICAL BARRIERS & IMMUNE SURVEILLANCE Celia, Darian, Lindsey, and Kathy

PHYSICAL BARRIERS

Purpose To prevent entry of bacteria and other substances or harmful toxins into the body Non-specific immune responses are often more rapid than specific immune responses

Examples Tears Wash harmful substances from the eyes and traps foreign material in the mucous membrane of the eye Sweat A natural antibacterial Increases the pH of your skin to 3-5pH.

Examples cont... Skin First defense of the innate immune system Acidity of our skin serves to kill foreign pathogens Cuts and burns allow pathogens to penetrate the skin

Mucous Membrane Examples cont... Can trap pathogens, which are then sneezed, coughed, washed away, or destroyed by chemicals Lines all body cavities open to the exterior and function as an additional physical barrier. Examples cont...

Examples cont... Saliva Contains digestive lysozymes that destroy bacteria Stomach Acids Destroy pathogens through secreted hydrochloric acid solutions and protein digestive enzymes

First Lines of Defense

IMMUNE SURVEILLANCE

The immune system patrols the body to recognize and destroy invading 1) pathogens AND 2) cancerous host cells

IMMUNE SURVEILLANCE PROCESS (general)

IMMUNE SURVEILLANCE definitions Natural Killer Cell (NK) Lymphocyte Innate (nonspecific) immunity Perforin “Pore forming protein” Found in NK Binds to enemy cell’s plasma membrane and forms a pore Pore lets granzymes into enemy cell “Doorman” Granzymes “Killer enzyme” Found in granules of NK Induce cell death “SWAT team” *Granules: tiny secretory vesicles

IMMUNE SURVEILLANCE PROCESS (general)

IMMUNE SURVEILLANCE IN CANCER DETECTION T Cell Receptors Antigens on the tumor cells are recognized by the T cell receptors Activated T Cells Can kill the tumor cells and then are referred to as Cytotoxic T Cells and Natural Killer Cells T Helper Cells Aid in the activation of T Cells and Natural Killer Cells Send signals to stimulate the T Cells and the Natural Killer Cells

IMMUNE SURVEILLANCE PROCESS in response to cancer INTERFERON inhibits cancer cell mitosis CANCER CELLS enhances directly attacks & destroys CYTOTOXIC T Cell NATURAL KILLER Cells MACROPHAGES secretes

CYTOTOXIC T cells NATURAL KILLER MACROPHAGES secrete toxic chemicals (exocytosis) NATURAL KILLER secrete toxic chemicals (exocytosis) MACROPHAGES engulfs pathogens (phagocytosis)