Topic 6.3 & 11.1 Immunity & Defense Against Infectious Disease

Essential Idea Immunity is based on recognition of self and Destruction of foreign material

Recognition of Self Every organism has unique molecules on the surface of its cells. These molecules are called ANTIGENS

Recognition of Self Foreign antigens vsSelf antigens Substances that can trigger an immune response External surface proteins unique to an organism Proteins & poly- saccharides Proteins & poly- saccharides See text page 466

Pollen grains

Allergic Response An immune response to a foreign antigen that is not a threat or an exaggerated response to a foreign antigen Antibody production Mast cell activation

Mast Cell and histamines Mast cell is an immune cell found in connective tissue It secretes histamine beneath the skin, near blood & lymphatic vessels Causes dilation of blood vessels Increases leakage of blood vessels to allow disease fighting white blood cells to enter the tissue

Symptoms of Allergies induced by Histamine Itching Fluid build up Sneezing Mucus secretion Inflammation Rash Swelling (anaphylaxis)

Blood Typing Antigens

Carry out the Blood Type Activity Agglutination - clumping See page

Pathogens are usually species specific Polio & measles only in humans Zoonosis is a pathogen that can cross species barriers Examples: Bird flu Link to CDC on Avian FluLink to CDC on Avian Flu Nipah Virus Link to WHO info on nipah virusLink to WHO info on nipah virus List of zoonosis disease by pathogen Link to WHO zoonosis disease agentsLink to WHO zoonosis disease agents

Antibiotics are ineffective against viruses! Over-use of antibiotics is accelerating the evolution of more harmful bacteria. We are running out of antibiotics that work and are selecting for diseases such as MRSA. Antibiotics are designed to disrupt structures or metabolic pathways in bacteria and fungi: cell walls and membranes DNA synthesis (replication) RNA polymerase Translation These do not exist or are very different in viruses, so the antibiotic will have no effect. Bacterial drug resisance, from Wiley Essential Biochemistry. Find out more here:

Click here for info on MRSA Link to the video at the right

Application: Florey and Chain’s experiments to test penicillin on bacterial infections in mice. Read pages 307 & 308 in text. Outline the experiments and results from Florey and Chain’s experiments. Find another scientific article about these experiments from a reliable source. Cite the source and summarize 3 additional facts you found.

Data Support for Antibiotic Resistance Complete the Data based Question on Page 310 Submit answers electronically by at the end of class.