The Immune System

The Immune System
• The First Lines of Defense:
– Skin
– Antimicrobial proteins
– Cilia
– Gastric Juice
– Symbiotic bacteria – your ‘microbiome’
This is directly from the Cliffs book . .
.so make sure you read that
• Second Line of Defense
– Phagocytes
– Complement – promote cell lysis
– Interferons - ‘interfere’ with viral reproduction
– Inflammatory response
Immune Response
• The Third Line of Defense:
– This targets specific antigens – any molecule that
can be identified as foreign
Major Histocompatibility Complex
• The MHC allows the immune system to
differentiate between self and non-self cells.
- Made up of glycoproteins
- Found on the membranes of all body cells
- 20 genes code for these; unlikely that two
people have the same set
• Primary Agent of the Immune Response
– B Cells – originate and mature in the Bone
– Respond to antigens through antigen receptors
called antibodies
• Y shaped proteins, 5 different classes
5 Classes of Antibodies
T cells
• Lymphocytes that originate in the bone marrow
but mature in the thymus gland
– Have antigen receptors, but they are not antibodies
– You should read up on the additional information . . .
Responses of the Immune System1.CELL MEDICATED
• Cell-mediated response
– Uses T cells to respond to any non self cell,
including cells invaded by pathogens.
Cell Mediated Response
The Humeral Response
• Involves most cells and responds to antigens
or pathogens
- B cells produce plasma cells
- B cells produce memory cells
- Macrophage and helper T cells stimulate
the production of additional B cells
Why aren’t we dead?
• 1. Antibodies
• 2. Vaccines
• 3. Passive Immunity – placenta, breast milk