blood typing - analyzes class of antigens found on red blood cells 

• must be matched for blood transfusions
• A blood - A antigens, B antibodies
• B blood - B antigens, A antibodies
• AB blood - A and B antigens, no antibodies
• O blood - no A or B antigens, A and B antibodies
• different blood types of blood mixed together >> clumping is possible

Rh factor - another group of antigens found on red blood cells 

• Rh-positive or Rh-negative (mostly Rh-positive)
• baby can be born anemic if mother creates antibodies against the baby’s blood during birth

monoclonal antibodies - specific for only a single antigenic determinant 

• antigens may have multiple determinants >> generates polyclonal antibodies when injected into organisms
• created from hybridoma (fusion of cancer and B cells)

evolution of immune system - started w/ restriction endonucleases to degrade foreign DNA 

• invertebrates developed self markers to figure out which cells to attack
• phagocytes - attack microbes, found in all animals
• lymphocytes - first originated in annelid earthworms
• lectins = ancestors of antibodies
  • binds to sugar molecules
• immune system fully evolved by sharks

AIDS - acquired immune deficiency syndrome due to human immunodeficiency virus 

• destroys CD4+ T cells >> body unable to respond to any foreign antigen
• HIV-infected cells only die after releasing replicated viruses
• HIV prevents cells from responding to HIV antigen, blocks transcription of MHC genes
• die of infection, can’t die of HIV
• inhibit protease >> inhibit viral assembly, possible treatment

antigen shifting - pathogen mutates frequently >> gets past immune system 

• 2ndary immune response rarely comes into play
• malaria - caused by Plasmodium falciparum
  • consumes hemoglobin
  • prevents blood cells from going to the spleen for repair
• DNA vaccines - uses T cells instead of B cells to defend
  • uses plasmid to mark pathogen

autoimmunity - immune system = source of problem 

• immune system fails to recognize self antigens
• leads to organ damage, inflammation
• stopped w/ corticosteroids, anti-inflammatory drugs

allergy - hypersensitivity to allergens 

• antihistamine blocks histamine receptor >> inhibits inflammatory response
• immediate hypersensitivity - B cell response, symptoms within seconds/minutes
  • IgE antibodies created instead of IgG
  • IgE do not circulate in blood, attaches to tissue cells >> makes cells secrete histamine
  • anaphylactic shock - uncontrolled blood pressure drop
• delayed hypersensitivity - T cell response, symptoms within 48 hours
  • contact dermatitis - caused by poison ivy, oak, sumac