How our Immune System Fights Infection the War














- Slides: 14
How our Immune System Fights Infection: the War Against Germs Innate Immunity Adaptive (Acquired) Immunity Passive Immunity
Washington University School of Medicine in St. Louis, Missouri
INNATE IMMUNE SYSTEM proteins are the first responders to defend against pathogens (germs) Bacteria are destroyed by defense proteins A B C D Dr. Robert Schreiber
Complement Cascade Classical Pathway Lectin Pathway Alternative Pathway Ag-Ab Complexes Lectin binds mannose on pathogens Pathogens or injured tissue C 1 , C 4, C 2 Lots of proteins protect you! It’s very complicated! MASPs C 4 C 2 C 3 Convertase C 3 b C 5 Convertase C 5 b Terminal Pathway b C 3 P D, F , FB • C 3 a (Inflammation) • C 3 b (Opsonization) • C 5 a (Inflammation) • C 5 b (Initiates MAC) Membrane Attack Complex C 5 b, C 6, C 7, C 8, C 9
Complement proteins also ‘tag’ pathogens for attack by special white blood cells: macrophages, neutrophils, natural killer cells Macrophage Complement-tagged pathogen
Macrophages ‘eat’ marked pathogens Macrophage
Neutrophils – a tiny little cell with powerful effects Neutrophils release chemicals that kill pathogens Neutrophils release gooey traps to kill pathogens (NETS = neutrophil extracellular traps) Nucleus has multiple ‘lobes’
The ADAPTIVE IMMUNE SYSTEM features special immune-fighting cells and killer antibodies Antibodies are “designer proteins” specific for pathogen pieces = antigen Lymphocytes = white blood cells called T and B cells
https: //www. thevaccinemom. com/tag/t-cell/
Antibodies are Y-shaped proteins that bind and destroy pathogens B-cells make antibodies to pieces of pathogens From Wikipedia
Antibodies are released into blood stream and seek out and destroy pathogens Antibodies in the bloodstream Antibodies attacking a virus
PASSIVE IMMUNITY– Someone else’s immunity is passed to you Clinical Trial ongoing infusing into sick COVID-19 patients, the plasma from someone who is now immune to COVID-19 as a temporary therapy
Summary Innate immunity kicks in right away (microseconds) and is very powerful - but sometimes gets fooled by a smart pathogens. Many proteins and cell types direct: complement proteins, macrophages, neutrophils, natural killer cells + + + Adaptive immunity takes several days to program T & B cells and then B cells release millions of antibodies Passive immunity (antibodies) from someone who has immunity provided to another who doesn’t have immunity: mother to baby, immune plasma infused into a sick person.
Help your Immune System Stay Strong! Eat Healthy Exercise Positive Attitude Graphics from Can. Stock Photo Thank You!!