T cell B cell stuff

• How do B cells become activated?

  • Antigen attaches to antibody on B cell membrane
  • Active Th cells bind to B cells presenting a specific antigen
  • Th cell releases cytokines
  • Which activate B cell
  • Divide by mitosis + differentiate
  • Into B effector cells/ B memory cells
  • B effector cells differentiate into plasma cells
  • Plasma cells produce antibodies
  • Specific to antigen of pathogens
• Whats the role of antibodies?

  Neutralisation:

  • Neutralize toxins by binding to them -> prevents cell damage

  Opsonisation:

  • Binds to pathogen
  • So it can be recognised by phagocytes
  • Engulf pathogen
  • Phagocytosis

  Agglutination:

  • Bind to multiple pathogens
  • Clump them together
  • So they can be englufed by phagocytosis
  • More effective phagocytosis
• How are T cells activated?

  • Phagocyte engulfs pathogen
  • Phagocyte becomes APC
  • Receptors on inactive T cell binds to complementary antigens on APC
  • T cell releases cytokines
  • T cells divide by mitosis + differentiate
  • Into Th cells/ Tk
• How does immune system deal with infected cells?

  • Host cell infected by pathogen
  • Host cell becomes an APC
  • Antigen on APC binds to CD4 receptor on inactive T cell
  • T cell releases cytokines
  • Divide by mitosis + differentiate
  • Into Th & Tk
  • Tk bind to infected cell
  • Initiates cell lysis
  • Killing infected cell
  • & Destroying virus
  • Preventing its spread
• How do viruses replicate in host cell?

  • Virus attaches to host cell
  • Releases nucleic acid into HC
  • Viral protein synthesis
  • Viral particles assembled
  • Viral particles burst out
  • Cell dies via cell lysis