CHAPTER 51 Animal Immune Systems PPT Notes 5 7 2014 immune system combats pathogens disease causing organisms to keep bacteria healthy o pathogens include bacteria parasites viruses fungi protists 3 methods to keep animals healthy o wounds heal after infection o most people who contract bacterial viral illness recover w o medication o people who acquire bacterial viral infections recover frequently do not contract same disease again barriers to pathogen entry eyes blinking wipes tears containing antibacterial enzyme lysozyme across eye ears hairs earwax trap pathogens in external ear passageway nose mucous secretions in nasal passage lining works w hairs to trap pathogens airways tracheal lining most pathogens trapped in mucus before reaching lungs lined w mucus secreting cells ciliated cells digestive tract saliva mucus trap pathogens low pH ins stomach destroys pathogens immunity resistance to protection against disease causing pathogens prevents individuals from contracting same disease twice immunization allowing immunity to a particular disease o o o o o o o vaccination introduction of weakened altered pathogen to prime immune system to fight infection innate immunity immune system cells that respond to foreign invaders all times nonspecific responds in same way to all antigens involves leukocytes white blood cells mast cells macrophages neutrophils are white blood cells alterted to presence of foreign invaders by antigens found on surface of pathogens only o antigens foreign molecule that initiates immune response innate response is immediate nonspecific but responds to groups of pathogens in humans inflammatory response process continues until foreign material eliminated wound repaired skin breaks pathogens enter wound 1 2 platelets release blood clotting proteins wound site 3 chemokines signaling molecules recruited by immune cells secreted by wounded tissues macrophages wound site form a gradient to mark path to site 4 mast cells release chemical messengers to constrict blood vessels near wound blood flow blood loss histamine other signaling molecules secreted by mast cells dilate blood vessels farther away from wound to permeability 5 neutrophils macrophages engulf digest pathogens through phagocytosis 6 cytokines secreted by macrophages cytokines attract other immune system cells to site activate cells involved in tissue repair induce fever elevated body temp that helps healing o adaptive immunity occurs when cells require activation cells lymphocytes respond in specific way to particular strains of bacteria viruses fungi that enter body lymphocytes o o contrast leukocytes of innate immune system formed matured activated transported in distinct components of immune system lymphocyte origin bone marrow lymphocyte maturation B cells mature in bone marrow 5 7 2014 T cells mature in thymus lymphocyte activation occurs in spleen lymph nodes lymphocytes recognize antigens lymphocyte transport occurs in lymphatic ducts blood vessels circulate through blood secondary organs of immune system lymph nodes spleen lymphatic ducts lymphatic ducts thin walled branching tubules that transport lymph throughout body in lymphatic system adaptive immune response acquired immune response based on interactions btwn immune system cells specific antigen antibodies proteins produced secreted by certain lymphocytes that bind to a specific part of a specific antigen 4 key characteristics of AIR specificity antibodies other components bind to specific sites on specific antigens diversity adaptive response recognizes limitless antigen array o o o memory adaptive response may be reactivated quickly if it recognizes antigens from previous infection self nonself recognition molecules produced by individual don t act as antigens o allows adaptive immune system to distinguish between self nonself if B cell receptor or T cell receptor responded to self molecule immune response autoimmunity anti self reaction that may lead to self destruction anti self T B cells destroyed before maturation o o o examples of autoimmunity o multiple sclerosis anti self T cells attack myelin sheath of nerve fibers muscular coordination problems rheumatoid arthritis T cells antibodies alter joint linings type 1 diabetes mellitus T cells attack kill insulin secreting cells in pancreas inability to regulate blood glucose levels 5 7 2014 5 7 2014 CHAPTER 51 Animal Immune Systems Blue Thread Questions If you understand the role of pattern recognition receptors you should be able to return to Figure 51 2 and predict how the same two groups of flies would respond to a Gram negative bacterial pathogen Draw a line on the graph to represent flies lacking the Toll protein after treatment and explain your reasoning Assume the survival rate of wild type flies would be similar to what is shown in the figure Describe how the following steps that first aid workers use when initially treating a wound mimic events in the innate immune response 1 Applying direct pressure to close blood vessels 2 Cleaning the wound to remove dirt and debris 3 Applying bandages containing compounds that half blood flow from the wound How do these events lead to the classical signs of an infection which include rubor reddening calor heat and tumor smelling among others 5 7 2014 If you understand how unique genes for the light and heavy chains of the BCR are made you should be able to calculate the number of different antigen specific BCRs that could be made by this process in 1 a human and 2 a single human B cell Cite two key events that must occur during lymphocyte maturation to ensure a safe and effective adaptive immune response Explain the benefit of assembling the variable region from discrete segments rather than having multiple intact variable regions You should be able to predict how the BCR locus in the genomic DNA of immature B cells is different from that in mature B cells 5 7 2014
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