Immunity and Infection Mr. Nagel

Meade High School

Think…

• What are the sources of illness in living organisms?

• What aspects of your body keep you healthy and resist these infections?

IB Syllabus Statements • 6.3.1

– Define pathogen. • 6.3.2

– Explain why antibiotics are effective against bacteria but not against viruses. • 6.3.3

– Outline the role of skin and mucous membranes in defence against pathogens. • 6.3.4

– Outline how phagocytic leucocytes ingest pathogens in the blood and in body tissues. • 6.3.5

– Distinguish between antigens and antibodies. • 6.3.6

– Explain antibody production. • 6.3.7

– Outline the effects of HIV on the immune system. • 6.3.8

– Discuss the cause, transmission and social implications of AIDS. • 11.1.1

– Describe the process of blood clotting. • 11.1.2

– Outline the principle of challenge and response, clonal selection and memory cells as the basis of immunity. • 11.1.3

– Define active and passive immunity. • 11.1.4

– Explain antibody production. • 11.1.5

– Describe the production of monoclonal antibodies and their use in diagnosis and in treatment. • 11.1.6

– Explain the principle of vaccination. • 11.1.7

– Discuss the benefits and dangers of vaccination.

• http://click4biology.info/c4b/6/hum6.3.htm

Pathogens and Antibiotics

• What makes us sick? – Bacteria, viruses, protists, fungi, parasites

• Why do we use antibiotics? – ANTIBIOTICS: Block metabolic pathways. – Flavors

• Bacteriocidal and Fungocidal (KILL KILL KILL!) • Bacteriostatic and Fungostatic (cease growth)

– Think: “Tactical Nukes” – Why won’t they work on viruses?

Primary Defenses (non-specific)

• Epithelial cells – Skin

• Epidermis (keratin) - surface with tougher cell walls • Dermis – lower layer with hairs, capillaries, and

sensory receptors – Mucous-covered tissue

• Cilia propel mucous from inside the longs to the epiglottis, where it is swallowed and bathed in acid

Secondary (non-specific)

• Phagocytic white blood cells – Macrophages “eat up” invaders (phagocytosis) – Think “Jabba the Hutt”

• Inflammatory Response – Secretion of chemical signals dilates and increases

permeability of capillaries • ex: histamine

– This allows blood clotting factors and phagocytes to respond to the ‘site of activity’

Tertiary Defense (Specific)

• Antigens – foreign molecule eliciting a response from B and T cells (white blood cells) often found on the outside surface of a cell – Ex: Blood types present various antigens

• Antibody (immunoglobulin or Ig) – secreted proteins by B cells in response to foreign molecules (“paint target”) – 2 heavy chains, 2 light chains

http://anthro.palomar.edu/blood/ABO_system.htm

Antibody Creation

• All blood cells come from Bone Marrow – B cells mature in the Bone Marrow – T cells mature in the Thymus

• Antigens stimulate B-cells to secrete additional antibodies AND also to produce Memory B-cells for subsequent infections

P 848, Campbell Biology

H.I.V. and A.I.D.S.

• HIV disables lymphocytes (B and T cells) • No ability to present antigens to T-cells • Immune system does not ‘counter’

infection because it does not believe it is under attack

• AIDS – Acquired (HIV transmission) – Immunodeficient (cannot be resisted) – Syndrome (manifestation of disease varies)

Why should we care about AIDS?

Vaccination – Why?

Odds and Ends

• Blood Clotting – http://users.rcn.com/jkimball.ma.ultranet/Biolo

gyPages/C/Clotting.html • MAB’s (Monoclonal Antibodies)

– http://www.cancer.org/docroot/ETO/content/ETO_1_4X_Monoclonal_Antibody_Therapy_Passive_Immunotherapy.asp

Loose Ends

• Viroids – Raw RNA that attacks plants – Why not animals?

• Prions – Malformed protein that alters surrounding

protein (ie Mad Cow)

Griffith

Hershey/Chase

Transformation/Transduction

• What does it mean to be transformed? – What is a transducer?

• How can information travel from one cell to another, even if it is killed?

• Can viruses be responsible for transferring the information?

• Notation: arg+ trp-

Transduction

• Describe the process of blood clotting. • Outline the principle of challenge and response,

clonal selection and memory cells as the basis of immunity.

• Define active and passive immunity. • Describe the production of monoclonal antibodies

and their use in diagnosis and in treatment. • Discuss the principles of vaccination. • Discuss the benefits and dangers of vaccination.