Micro lecture 9 - Immunity and Antimicrobials PDF

9 Immunology What is immunology?  The study of how body defends itself against foreign bodies What is the immune system?  Thegroup of cells and tissues responsible for protection of the body Components of the immune system Innate immune Adaptive system immune...

9 Immunology What is immunology?  The study of how body defends itself against foreign bodies What is the immune system?  Thegroup of cells and tissues responsible for protection of the body Components of the immune system Innate immune Adaptive system immune system Difference between innate and adaptive immune response Innate immune response Adaptive immune response Time Immediate reaction Takes time Specificity Not specific Specific Components Macrophages, Natural Cytotoxic T cells, B cells killer cells Memory No memory Memory Innate immune system  1. Intact skin and mucous membranes  2. Acids and enzymes  3. Normal flora  4. Inflammation  5. Cells First barrier in the immune system  Intact skin and mucous membrane  Acids and enzymes that kill microorganisms (like acids in the stomach)  Normal flora: competing for nutrients, space occupying and secreting antibacterial substance Innate immune system  Inflammation dilutes toxins and limit spread of infection Cells of the innate immune system  Phagocytes: ‫الخاليا البالعة‬  Natural killer cells: ‫الخاليا القاتلة‬ Adaptive immune system  Humoral immune response  Cell-mediated immune response Humoral immune system Mediated by B-lymphocytes )‫(االمصال‬B-lymphocytes secrete antibodies  Antibodies are specific for target antigensِ Antigen and antibody like lock and key Antigen: It is the foreign substance that the immune system react to. Antibody: Proteins found in the body that react against specific antigens (like lock and key) Cell mediated immune response  Mediated by T-lymphocyte  T-lymphocytes can be T-helper or Cytotoxic T cells  T-Lymphocytes T-Helper Cytotoxic T-lymphocytes  T-Helper:Help other cells of  T-Cytotoxic:Kill infected the immune system by cells as natural killer cells secreting cytokines do (activation or inhibition)  Acquired immunity Active (immunity made by Passive (immunity passed the body) to the body) Exposure to Mother to Antisera Vaccination disease baby Clinical applications of immunology  Immune system can attack the body if there is fault in the immune response leading to autoimmune disease ( ‫االمراض‬ )‫المناعية مثل الذئبة الحمراء و الصدفية و الحساسية‬  Immune system is protective against bacteria, viruses and tumors and immune components can be used in treatment of many diseases.  Vaccines can be protective against many diseases and can be given as active vaccination or passive vaccination  10 Antimicrobials What are antimicrobials?  Agentsthat kill or inhibit the growth of bacteria  Spectrum of antimicrobials Wide spectrum Narrow spectrum Against gram positive and Against gram positive or gram gram negative bacteria negative bacteria Culture and sensitivity  To know the causative organism of a disease specimens should be collected and cultured )‫(المزارع مثل مزرعة البول‬  If the causative agent is bacterial then we should perform sensitivity tests to know which antibiotic to use.  Before performing culture and sensitivity the patient should not take any antibiotics so the results are not affected.  Antibiotics are selected if the bacteria is sensitive to it but if resistant it is not selected Culture and sensitivity Antimicrobials mechanism of action Properties of ideal antibiotic  Not toxic to the body  Killing activity against bacteria not just inhibitory  Broad spectrum  Easy to take  Don’t cause allergy (‫)حساسية‬  No resistance against the antibiotic Complications of antimicrobial therapy  Super infection: overgrowth of microbial flora due to disturbed balance between bacteria.  Drug toxicity: some antibiotics are toxic to kidneys  Allergy: some antibiotics cause skin allergies or systemic allergies and can cause death.  Drug resistance: due to abuse of antibiotics (wrong choice, use antibiotics when not indicated, not completing treatment course) Test Yourself!  Quiz 1. An ideal antimicrobial agent is characterized by which of the following : a) Broad spectrum activity. b) Toxic to the host. c) Inhibitory to bacteria d) Produce allergy. 2. Which of the following best describes innate immune response: a) I takes time to react against b) First defense of the body c) IT is specific to antigens. d) IT produces immunological memory Thank You!