Sir aries 2nd trinal exam

• Functional components of immune system
• Types of Immunity


  • Natural
  • Artificial
• Natural Immunity


  • Active
  • Passive
• Artificial Immunity


  • Active
  • Passive
• Immunoglobulins


  Glycoprotein molecules produced by plasma cells (white blood cells) that act as a critical part of the immune response by specifically recognizing and binding to particular antigens
• Five categories of Immunoglobulins

  • IgA
  • IgD
  • IgE
  • IgG
  • IgM
• Types of Parenteral Immunoglobulins


  • Hepatitis B immune globulin (HBIg)
  • Rabies immunoglobulin (RIG)
  • Gamma globulin
• Antisera


  • Anti-tetanus serum
  • Anti-rabies serum
  • Venom Antiserum
• Vaccines


  • BCG (Bacillus Calmette Guerin)
  • HBV (Hepa B vaccine)
  • DPT (Diphtheria Pertussis & Tetanus)
  • TT (Tetanus Toxoid)
  • Td (Tetanus Diphtheria)
  • PCV (Pneumococcal vaccine)
  • OPV (Oral Polio Vaccine)
  • IPV (Inactivated Polio Vaccine)
  • HPV (Human Papilloma Virus) vaccine
  • Flu Vaccine
  • Rotavirus vaccine
• Herd immunity


  The overall level of immunity in a community and is relevant in the control of epidemic diseases. When a large proportion of community (herd) are immune to a pathogen, the herd immunity to the pathogen is satisfactory.
• Interactions between the two systems: innate (nonspecific) defenses, which protect against microorganisms in general, and adaptive (specific) immunity, which protects against a particular microorganism.
• External defenses


  • Skin
  • Mucous membranes
  • Secretions
• Internal defenses


  • Phagocytic cells
  • Antimicrobial proteins
  • Inflammatory response
  • Natural killer cells
  • Humoral response (antibodies)
  • Cell-mediated response (cytotoxic lymphocytes)
• Components of Innate Immune System

  • Anatomical Barriers - Mechanical Factors
  • Anatomical Barriers - Chemical Factors
  • Complement proteins
  • Coagulation proteins
  • Cytokines
  • White blood cells
• White blood cells (WBCs)

  • Macrophages
  • B-lymphocytes
  • T-lymphocytes
  • Natural killer(NK) cells
  • Mast cells
  • Neutrophils
• Phagocytosis


  The process where white blood cells (e.g. Neutrophils) find, eat and digest microbes
• Monocytes


  Migrate into the tissues and become Macrophages
• Macrophages


  Phagocytosis of microbes in tissue (neutrophils are present only in blood)
• Natural Killer Cells


  Important part of the innate immune system, kill virus /bacteria infected cells (Intracellular pathogens) and cancer cells
• Toll-Like Receptors (TLRs)


  Transmembrane proteins present on macrophages and few other cells, conserved across vertebrates, important part of innate immune system that look out for and bind to microbes (or their components) to trigger a cascade of events to kill or protect against pathogens
• What happens when a TLR binds to a microbe

  1. Inflammation

  2. Secretion of Cytokines / Interferon

  3. Phagocytosis of an infected cell

  4. Apoptosis of infected cell

  5. Enhanced immune response

  6. Killing of infected cell
• Cells that release cytokines

  • Neutrophils
  • Macrophages
  • TLRs
  • NK cells
  • Lymphocytes
• Examples of cytokines


  • Interferons
  • Interleukins
  • Tumor Necrosis Factor (TNF)
• Interferons (IFN)


  Signalling proteins produced by virus infected monocytes and lymphocytes that "interfere" with virus replication and warn neighbouring cells of a virus
• How interferons inhibit viruses

  1. Host protein induction

  2. Cascade of events

  3. Activation of inactive host protein

  4. Inhibition of host protein synthesis to prevent virus replication
• Interleukins


  Not stored inside cells, quickly synthesized and secreted in response to infection, key modulators of behaviour of immune cells, mostly secreted by T-lymphocytes & macrophages
• Tumor Necrosis Factor (TNF)


  Kills cancer, causes fever, and inflammation
• Complement (C')


  A large number of distinct plasma proteins that react with one another (C1 - C9), can bind to microbes and coat them, essential part of innate immune response, enhances adaptive immune response
• How complement proteins facilitate phagocytosis

  Bacteria coated with C' are recognised by neutrophils with C' receptors, initiating phagocytosis
• How complement proteins lyse pathogens

  Membrane attack complex formed by C' proteins
• Coagulation proteins


  Involved in the complex pathway of blood clotting to stop bleeding after injury, includes platelets and vitamin K
• Inflammation refers to the body's process of fighting against harmful materials, infections, injuries, and toxins, in an attempt to heal itself
• Five cardinal signs of inflammation

  • Redness (rubor)
  • Swelling (tumor)
  • Heat (calor)
  • Pain (dolor)
  • Loss of function (functio laesa)
• Signs of inflammation


  • Vascular changes
  • Vasodilatation
  • Capillary permeability
  • Heat / redness
  • Temporary loss of function
  • Fever
  • Swelling
  • Pain
• Microbial pathogenesis


  Entry into the host, penetrate or evade host defenses, and damage tissue to cause disease
• Portals of entry


  • Mucous membranes
  • Skin
  • Parenteral
• Microbial mechanisms of pathogenicity

  1. Access and adhere to host tissues

  2. Penetrate or evade host defenses

  3. Damage tissue to cause disease
• Mucous membranes


  • Epithelial tissue lining the respiratory tract, gastrointestinal tract, genitourinary tract, and conjunctiva
• Respiratory tract


  Easiest and most frequently used entry site for microbes
• Gastrointestinal tract


  Another common entry site, enter through water, food, contaminated fingers, and fomites, must survive stomach HCl, enzymes, and bile