How does our body protect itself? This blog posts will introduce the higher level IBDP Biology content of specific immune response within our human bodies, let's go!
Identifying Pathogens Revision
Every body cell has a common set of plasma membrane proteins. White Blood Cells recognize the set of proteins that are "self". Pathogens has different proteins (Antigens) that are "not self" and this causes the production of Antibodies
Antigens: Any molecule that can trigger an immune response leading to generation of antibodies
Antibodies are specific to antigens therefore foreign antigens are recognized and antibodies are then produced
ABO blood type classification uses the presence/absence of a certain antigen on red blood cells
Specific Immune Response
- Pathogens ingested by Macrophages
- Antigens from the pathogen are now displayed in the plasma membrane of Macrophage
- Helper T cells bind to the antigens displayed by the Macrophages
- When Helper T cells bind to the antiges Helper T cells are activated by the Macrophage
- The activated T cells then bind to Lympocytes called B cells
- The Helper T cell activates the selected B cell through
binding and also releasing a signalling protein
- Macrophages ingest pathogens via phagocytosis and present the antigen on their surface
- Helper T cells bind to the antigens displayed on the Macrophages and become activated
- Activated T cells bind with B cells while causing the B cells to activate through binding and release of a signalling protein
- Activated B cells rapidly divide by mitosis to form plasma cells that produce a large number of specific antibodies
- Antibodies destroy the pathogen
- Antibodies and plasma cells persist temporarily
Small number of plasma cells remain long after infection and become memory cells
Memory cells are then inactive till the body faces the same pathogen then allowing the memory cells to become activated leading to a faster response
Macrophage presents antigen
- Helper T lymphocyte becomes activated
- B lympocyte becomes activated
- Plasma - secrete antibodies
- Memory - long lived in bloodstream
That is all for the introduction of the immune system!
References:
- https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.p3mountains.org%2Fpost%2Fpathogens&psig=AOvVaw0QoxOctFimyNw1gXI34mUX&ust=1626201742099000&source=images&cd=vfe&ved=0CAoQjRxqFwoTCPiN9duX3vECFQAAAAAdAAAAABAD
- https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.istockphoto.com%2Fvector%2Fcell-mediated-immunity-gm524530218-92208787&psig=AOvVaw39CGygeOW3Jbu1pfnQRXkK&ust=1626201848918000&source=images&cd=vfe&ved=0CAoQjRxqFwoTCLj9nI-Y3vECFQAAAAAdAAAAABAb
Drafted by Venetia (Biology)