OUR IMMUNE SYSTEM

What is our immune system? A system of biological structures and processes within an organism that protects against disease. Must detect a wide variety of agents, known as pathogens, from viruses to parasitic worms, and distinguish them from the organism's own healthy tissue.

Immunology Branch of biomedical science that covers the study of all aspects of the immune system in all organisms.

Two parts to the immune system Innate Adaptive

Innate Immune System The body’s first line of defense A non-specific series of defense mechanisms in our body utilized to fight off infections when it first occurs Recognizes pathogens from healthy tissue and acts right away

What are some examples we can think of? Surface Skin, exoskeleton (on insects), mucus, our own bacteria Inflammation First sign of infection, increased blood flow to site of damaged tissue – bringing white and red blood cells for protection and repair against pathogens Cell protection Natural Killer cells Cells which recognize damaged cells (virus infected, tumorous etc.) and eliminate them

Innate immune system Kicks in for the first 0-12h following an infection If pathogen persists past that point, our body utilizes our Adaptive Immune system to begin fighting off infection

Adaptive Immune System Acquired immune system Comprised of a series of highly systematic cells utilized to fighting off, eliminating, and recognizing pathogens.

Adaptive Immune System Produces cells which are highly specific to different pathogens Comprised of B-Cells, and T-Cells

B-Cells Produce our antibodies (IgA, IgG, IgE, IgM, IgD) Each antibody is specific to a certain pathogen. Antibodies circulate our system until it finds it’s specific antigen.

B-Cells Once pathogen has been recognized, B-cell produces more antibodies to neutralize pathogens B-cells then display the antigen on it’s surface so that T-cells can then recognize the antigen and get to work. Antigen is the part of a foreign substance which elicits an immune response

T-Cells Originate from the thymus 5 different types of T-cells Helper Cytotoxic Memory Regulatory Natural Killer

Helper T-Cells Assist white blood cells with the immunological processes Developing Memory B-Cells Produce cytokines which aid in the active immune response

Cytotoxic T-Cells Destroy virus-infected cells and tumor cells, and are also implicated in transplant rejection

Memory T-Cells Antigen-specific T cells that persist long-term after an infection has resolved Provides immune system with “memory” of past infections

Regulatory T-Cells Immunological tolerance Keeps our immune system from “over-reacting” Allergies Host bacteria Autoimmune disorders

Natural Killer T-Cells Not to be confused with NK cells of innate immune system Purpose is to eliminate cells displaying antigens Can recognize tumor cells, and cells infected with the herpes virus.