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What is immunity?

What is immunity?. Resistance to a disease causing organism or harmful substance Two types Active Immunity Passive Immunity. Active Immunity. This is immunity where the body is “actively” producing antibodies to fight infection. The body produces the antibodies.

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What is immunity?

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  1. What is immunity? • Resistance to a disease causing organism or harmful substance • Two types • Active Immunity • Passive Immunity

  2. Active Immunity • This is immunity where the body is “actively” producing antibodies to fight infection. • The body produces the antibodies. • Your body has been exposed to the antigen in the past either through: • (Natural)-Exposure to the actual disease causing antigen • (Induced)-Vaccines • What is this second type of exposure called?

  3. Vaccine • Vaccination:An injection of a weakened strain of an infectious microbe (pathogen) that causes the body to undergo active immunity (produce antibodies). Because the bacteria has been killed or weakened, minimal symptoms occur.

  4. How long does active immunity last? • It depends on the antigen • Some disease-causing bacteria multiply into new forms that our body doesn’t recognize, requiring annual vaccinations, like the flu shot • Booster shot - reminds the immune system of the antigen • Others last for a lifetime.

  5. Passive Immunity The body doesn’t produce the antibodies. This is immunity where antibodies are given to a person from the blood of another person or animal. This immunity only lasts for a short period of time. • Natural:A mother will pass antibodies on to her baby during pregnancy and through breast milk. • Artificial:the injection of antibodies.

  6. Immune system in plants Mechanical barrier Chemical barrier -oil Chemicals gums • -cuticle • epidermis

  7. Adverse Events associated with Immunity ??????????????????????????

  8. Immune deficiency Immune deficiency is a malfunction or a deficiency in one or more components of the immune system.

  9. Acquired Immune Deficiency Syndrome(AIDS) • Caused by the Human Immunodeficiency Virus • Specifically targets and kills T-cells • Because normal body cells are unaffected, immune response is not launched

  10. Autoimmune Disease • Autoimmune diseases are diseases where the immune system begins to attack itself. • Ex: • Rheumatoid Arthritis – crippling disease of the joints. • Multiple Sclerosis – disease of nervous system • Cause(s): unknown • Cures/Treatments: No known cures. Usually treated with drugs.

  11. Blood group

  12. Mixing blood from two incompatable individuals can lead to blood clumping or agglutination. The clumped red cells can cause toxic reactions.

  13. Rh factor blood grouping system • If theredblood cells which also needs to be considered. It is called the Rhesus-D antigen. So that increases number of blood types to eight (A Rh+, A Rh-, B Rh+, B Rh-, AB Rh+, AB Rh-, O Rh+, O Rh-).

  14. Rhesus incompatibility

  15. Rh factor • Problems can occur during pregnancy when the baby's blood has the Rh factor and the mother's blood does not . • During delivery baby’s blood enters mothers blood stream and mother’s body produces antibody against the Rh factor. Second time when the mother conceives a Rh+ child the antibodys in mothers blood destroy baby’s red blood cells leading to death. This is called haemolytic disease. • Most Rh disease can be prevented by treating the mother during pregnancy or promptly (within 72 hours) after childbirth. The mother is given an injection of anti-Rh antibodies. This is done so that the featalRhesus D positive erythrocytes are destroyed before her immune system can discover them.

  16. Immune DisordersAllergies Allergy - An exaggerated response by the immune system to otherwise harmless substances called allergens. Allergen: a normally harmless substance that causes an allergic reaction. ex: dust, pollen, mould, food, insect stings Types of Allergic reactions There are two types of allergic reactions. a. Immediate – occurs within seconds and normally lasts for about 30 minutes.Mast cell-mediated b. Delayed – takes longer to react and can last for a much longer time.Mediated by T cells

  17. What happens during an allergic reaction? • When an allergen comes in contact with the body the body produces antibody called immunoglobulin (IgE). • Mast cells capture and display (IgE). When the allergen comes in contact second time it binds to IgE. This activates the mast cell which inturn releases histamines. Inside mast cells are small granules that contain histamine. Histamines cause: a. blood vessels to widen and become leaky. Release of fluids cause runny nose . b. Histamine causes smooth muscles to constrict Anaphylaxis or anaphylactic shock: This is the sudden and severe allergic reaction to a substance that can cause death. Treatments for Allergies • Avoidance of material – especially food. • Epinephrine • Antihistamines

  18. Allergies • Histamine causes blood vessels to widen and become leaky. • Fluid and white blood cells leave capillaries. • The area of leakage becomes hot, red and inflamed • Histamine causes smooth muscles to constrict.

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