Lecture 03, 4

• What is the primary function of the immune system?

  To protect the body from pathogens
• What is the role of B cells in the immune system?

  They produce antibodies to fight infections
• Where do B cells develop?

  In the bone marrow
• What is an epitope?

  A specific part of an antigen recognised by antibodies
• What do plasma cells primarily do?

  Secrete antibodies
• How can plasma cells be detected in serum?

  By measuring antibody response
• What is the function of T cells?

  Recognise and respond to antigens
• What is clonal expansion in T cells?

  Formation of identical cells from specific binding
• What do cytotoxic T cells do?

  Initiate cell death in infected cells
• What is the role of MHC molecules?

  Present antigen fragments to T cells

  
• What is the difference between MHC Class I and Class II?

  Class I presents endogenous antigens, Class II exogenous
• What happens when CD8+ T cells recognise an antigen?

  They initiate cell death of infected cells
• What is a characteristic of Type I hypersensitivity?

  Rapid allergic reaction
• How does penicillin induce Type II hypersensitivity?

  It transforms erythrocytes to appear foreign
• What is a common consequence of autoimmune diseases?

  Immune system attacks the body's own cells
• What is the role of Natural Killer (NK) cells?

  Kill host cells if activation exceeds inhibition
• What is the effect of HIV on the immune system?

  It targets CD4+ T cells
• What are the types of hypersensitivity reactions?

  • Type I: Immediate hypersensitivity (allergies)
  • Type II: Cytotoxic hypersensitivity (e.g., penicillin)
  • Type III: Immune complex-mediated hypersensitivity
  • Type IV: Delayed-type hypersensitivity (e.g., TB response)
• What are the differences between MHC Class I and Class II in terms of antigen presentation?

  • Class I:
  • Presents endogenous antigens
  • Found on most nucleated cells
  • Class II:
  • Presents exogenous antigens
  • Primarily on APCs (e.g., dendritic cells, macrophages)
• What are the consequences of immune dysfunction?

  • Hypersensitivity reactions
  • Autoimmune diseases
  • Immunodeficiency diseases
• What is the role of memory cells in the immune response?

  • Provide quicker response upon re-exposure
  • Maintain specificity for previously encountered antigens
• What is the significance of the thymus in T cell development?

  • Site of T cell maturation
  • Regulates immune response
  • Becomes less effective with age
• How do allergens affect the immune system?

  • Elicit allergic reactions
  • Trigger mast cell activation
  • Can cause hypersensitivity responses
• What is the impact of estrogen on autoimmune diseases?

  • Enhances immune response
  • Increases susceptibility in females
  • Affects immune function during menopause
• What is the role of cytokines in the immune response?

  • Tailor immune response
  • Activate T cells and macrophages
  • Regulate inflammation
• What is the function of granzymes and perforin in cytotoxic T cells?

  • Induce programmed cell death
  • Target infected or cancerous cells
• What is the significance of the reticular network in lymph nodes?

  • Supports lymphocyte interaction
  • Facilitates antigen response