Allergy, Autoimmunity and cancer

Learning objectives To look at topics associated with immunity and understand the link to allergies and autoimmunity To understand what a cancer is.

Who here has allergies? List them:

Allergies An immune reaction to a harmless substance. Tendency to be allergic can be inherited Common allergies are pollen, dust, mold spores, venoms, cat saliva, peanuts. These are known as allergens and symptoms result when they trigger an allergic response, Body mistakes allergens for pathogens

An allergic response 5. Stimulates mast cells to release histamines promoting inflammatory response 4. Re-exposure results in allergen binding to antibodies on mast cells 3. Allergy antibodies bind to mast cells 2. Plasma cells produce allergy antibodies instead of disease fighting ones st exposure stimulates b cells to produce allergy plasma cells (instead of useful disease fighting ones)

Anaphylaxis An extreme inflammatory response vessels become very leaky,Throat and breathing tubes may become very constricted and blockedFluids flood out of the blood vesselsBlood pressure drops very lowTreated with an injection from an epi-pen Long term treatment can include aversion therapy with injections of the allergen which serve to reduce allergen related antibodies and thus reduce seriousness of allergic response.

Autoimmune diseases These occur when the body misreads its own antigens and turns on itself Common autoimmune diseases include rheumatoid arthritis, Type 1 diabetes, pernicious anaemia, lupus, myasthenia gravis and multiple sclerosis. (interestingly these were many of the diseases the anti- vaccination lobby identified as being linked to vaccination)

Immunodeficiency Can be congenital (born with it)Acquired (AIDS) Medical – the result of immunosuppressive drugs to treat cancers or prevent rejection of transplants.

SCID Severe Combined Immune DeficiencyA rare recessive genetic condition Person born with it lacks the ability to make immune cells due to a deficient gene.

HIV AIDS HIV = Human immunodeficiency virusAIDS = acquired immune deficiency syndrome HIV is a virus that infects and destroys helper T cells, thus effectively paralysing the specific immune system. As your T Cell count falls you become increasingly less able to mount an immune response to pathogen invasions so that increasingly, common, harmless pathogens become deadly.

HIV virus infecting a helper T Cell

Cancer Cancers are? result of the failure of the mechanism that controls the division of body cells.Uncontrolled growth by cell division to form a tumourOccur all the timeNormally killed by cytotoxic T cells as they develop slightly different antigens Some grow too quickly or suppress body’s immune system or evade identification because antigens are unchanged. Kill you by taking resources from body, producing toxins, squeezing out existing organs and possibly producing hormones.

Homework 3 (reminder) Immunity in your own wordsDescribe what happens when an invader enters your body – your non specific responseExplain what happens if the normal mechanisms of protection failExplain how your body learns to recognize and fight the invadersExplain how this leads to immunity and how the memory is stored.Minimum 2 sides. Use diagrams where possible to help explanations.You must include at least 2 references.