Specific Immune Response Flashcards
Where are B cells produced?
Bone marrow
Where do B cells mature?
Bone marrow
Explain the activation of B cells - 7
- B cells are covered in antibodies
- Antibodies bind to antigens to form antibody-antigen complex
- Each B cell has different shaped antibodies so each will bind to a different complementary antigen
- Activated T helper cell with complementary receptors binds to APC
- Produces cytokines that stimulate B cell
- B cell divides by mitosis to form B memory cell and plasma cells
- Plasma cells release antibodies
What are the 4 types of antibody defence?
- Phagocytosis
- Aggulating pathogens
- Neutralising toxins
- Preventing pathogen binding
Explain how antibodies are involved in phagocytosis 2
- Antibodies bind to antigens and label them
- Macrophage engulf antibodies and pathogen and phagocytosis occurs
Explain how antibodies neutralise toxins 3
- Antibodies bind to toxins from pathogens
- Prevent toxins from affecting human cells so toxins are neutralised
- Toxin-antibody complexes phagocytosised
Explain how antibodies prevent pathogen binding 3
- Antibodies bind to antigens on pathogens
- Blocks cell surface receptors
- Pathogens cannot bind to host cells to infect them
What are antibodies made up of?
- 4 polypeptide chains
- Two heavy chains
- Two light chains
- Each chain made up of variable region and constant region
- Each heavy chain has a hinge region
What are the variable regions in antibodies?
- Antigen binding sites
- Different amino acid sequence so different shape for each antibody
- Complementary to particular antigen
What are the hinge regions in antibodies?
Areas allowing flexibility for when antibodies bind to antigens
What are the constant regions in antibodies? 2
- Regions for binding to receptors on immune system cells e.g phagocytes
- They all have the same amino acid sequence so same shape
What holds the polypeptide chains in an antibody together?
Disulphide bridges
Give the 2 types of antibody
- Membrane bound
- Secreted
What are membrane bound antibodies?
Antibodies attached to the membrane of a B cell
What do membrane bound antibodies have that secreted antibodies do not?
Extra section of protein in the heavy chain anchoring them to the B cell membrane