immunity against bact. & fungi

• What is the first phase of the immune response?

  Inflammation (Innate)

  
• What is the role of the skin in the immune system?

  It acts as a mechanical barrier against microbes

  
• How does the acidic environment of the skin help in immunity?

  It retards the growth of microbes
• What is the function of mucous membranes in the immune system?

  They entrap foreign microbes
• What is the role of temperature in the immune response?

  It inhibits the growth of some pathogens

  
• What do chemical mediators like lysozyme do?

  They cleave bacterial cell walls
• What is the function of phagocytic cells in the immune system?

  They internalize and break down foreign macromolecules

  
• What triggers the inflammatory response?

  Tissue damage and infection
• What are the phases of the immune response?

  1. Inflammation (Innate)
  2. Activation of the adaptive immune system
  3. Resistance to re-infection (Adaptive)

  
• How are T cells activated in the immune response?

  By MHC I and MHC II presentation

  
• What do dendritic cells do in the immune response?

  They activate specific TH and TC cells

  
• What type of cells do TH cells help?

  B cells and TC cells
• What cytokines do TH1 cells produce?

  IFN-γ, IL-2, and TNFα

  
• What is the role of TH2 cells?

  They are appropriate for parasitic infections
• What do TH17 cells respond to?

  Extracellular bacteria and fungi

  
• What are the roles of TC cells?

  • Recognize infected cells via MHC I
  • Kill infected cells using perforin
  • Proliferate with IL-2 from TH cells
• What is the primary antibody produced in a primary response?

  IgM antibody

  
• What is the function of antibodies in the immune response?

  They bind to pathogens and neutralize them

  
• What are the five groups of infectious agents?

  1. Viruses
  2. Bacteria
  3. Fungi
  4. Protozoa
  5. Helminths (worms)
• What is the role of cytotoxic T cells in protective immunity?

  They kill infected cells

  
• What is the size range of bacteria?

  0.3-5 mm
• What are examples of extracellular bacteria and the diseases they cause?

  • Bacillus anthracis: Anthrax
  • Escherichia coli O157:H7: Hemorrhagic colitis
  • Streptococcus pneumoniae: Pneumonia

  
• What are examples of intracellular bacteria and the diseases they cause?

  • Mycobacterium tuberculosis: Tuberculosis
  • Chlamydia trachomatis: Eye and genital diseases
  • Listeria monocytogenes: Listeriosis

  
• What is the role of macrophages in bacterial infection?

  They recognize and opsonize bacteria

  
• What do pattern recognition receptors (PRRs) do?

  They recognize bacterial products and surfaces

  
• What do macrophages release in response to infection?

  Inflammatory cytokines

  
• What is the function of antibodies in relation to toxins?

  They bind and neutralize toxins

  
• What are the main responses to extracellular bacteria?

  • Complement opsonization for phagocytosis
  • Direct lysis via MAC formation
  • Phagocytosis by macrophages and neutrophils

  
• What are the key components of the innate immune response?

  • Complement system
  • Phagocytosis
  • Inflammatory cytokine production

  
• What type of capsule do some bacteria have that is not recognized by macrophage receptors?

  Thick polysaccharide capsule
• How do intracellular bacteria evade macrophage response?

  By growing in phagosomes

  
• What is the role of macrophages in bacterial infection?

  • Killing by phagocytes
  • Release inflammatory mediators
  • Contribute to host defense

  
• What are Pattern Recognition Receptors (PRRs)?

  Receptors that recognize pathogens

  
• Name two inflammatory cytokines released by macrophages.

  IL-1 and TNFα

  
• What is the effect of macrophages on body temperature during infection?

  They elevate body temperature
• What are the mechanisms by which antibodies protect against extracellular bacteria?

  • Bind and neutralize toxins
  • Opsonize bacteria for phagocytosis
  • Induce complement cascade
  • Label bacteria for phagocyte recognition

  
• How do antibodies opsonize bacteria?

  By interacting with phagocyte Fc receptors

  
• What is the role of IgG in bacterial immunity?

  Blocks binding to receptors

  
• What is the function of the Fab portion of antibodies?

  Made against epitopes of adherence
• What is the role of TH cells in the immune response to intracellular bacteria?

  Produce cytokines to activate macrophages