Acquired immunity Expected learning: To gain an understanding of acquired immunity and what it does

WHAT IS IT?? ACQUIRED IMMUNITY - immunity that is not inherited. Acquired immunity can be active or passive. Active immunity is the result obtained through development of antibodies in response to an antigen, as from exposure to an infectious disease or vaccination. Passive immunity results from the transmission of antibodies, as from mother to fetus through the placenta or by the injection of antiserum.

DEFINITIONS Antibodies: proteins generally found in the blood that detect and destroy invaders, like bacteria and viruses Antigen: A substance that when introduced into the body stimulates the production of an antibody. Antigens include toxins, bacteria, foreign blood cells, and the cells of transported organs. Antiserum: a serum containing antibodies that are specific for one or more antigens. Serum: The clear liquid that can be separated from clotted blood. Serum differs from plasma, the liquid portion of normal unclotted blood containing the red and white cells and platelets. It is the clot that makes the difference between serum and plasma.

IMMUNITY

INNATE IMMUNITY The natural resistance that a person is born with Provides resistance through physical, cellular and chemical approaches Prevents colonisation, entry and spread of microbes

ADAPTIVE IMMUNITY Can be sub-divided into two groups; Natural or Artificial Natural acquired immunity will occur through a disease causing agent (not deliberate) Artificially acquired immunity can be developed through vaccines (deliberate) Natural and artificially acquired immunity can be further sub-divided into Passive or Active immunity

PASSIVE IMMUNITY - NATURAL Passive immunity: A type of immunity acquired by the transfer of antibody from one individual to another, such as from mother to offspring Can occur naturally: When maternal antibodies are transferred to the fetus through the placenta during the third month of gestation iGg is the only antibody that can pass through the placenta to the fetus Antibodies (iGa) are also naturally transferred through breast milk Transferred in the stomach of the infant to protect against bacterial infections This will protect the new born until they can synthesise their own antibodies

PASSIVE IMMUNITY - ARTIFICIAL Artificially acquired immunity: short-term transfer of antibodies through an immunisation These antibodies can be administered in a few ways: As human or animal blood plasma As pooled human immunoglobulin for intravenous (IVIG) Intramuscular use (IG) Monoclonal antibodies (Mab) Used to prevent diseases Fights against immune deficiency (inability to fight infectious diseases) Treats poisonings Disadvantages: only lasts a short period of time Potential risk of hypersensitive (various allergic) reactions Risk of serum sickness (exposure from antibodies obtained from animals)

ACTIVE IMMUNITY - NATURAL Active immunity: A type of immunity or resistance developed in an organism by its own production of antibodies in response to an exposure to an antigen, a pathogen or to a vaccine Can occur naturally: When a person comes into contact with a particular disease-causing organism for the first time (because no antibodies will be present) Immunity will be acquired naturally after infection After a person has been infected with a certain disease once, antibodies can quickly act on and kill the virus if it invades the body a second time

ACTIVE IMMUNITY - ARTIFICIAL Artificial immunity: a substance that contains antigens released into the body through things such as vaccines how can these antigens be released into the body? Vaccines – that contain dead or treated living micro-organisms. These activate the immune system to produce antibodies against specific disease-causing organisms without actually causing the disease http://www.youtube.com/watch?v=PNTDpxsrNGM

Reflection Question What are the two types of acquired immunity??