Immunology. Lecture ( 7 ) Dr, Baha,Hamdi,AL-Amedi Ph. D.Microbiology HOST DEFENSE

Transcription

1 Immunology Lecture ( 7 ) Dr, Baha,Hamdi,AL-Amedi Ph. D.Microbiology HOST DEFENSE

2 The Origin of Immune Concept-I The term Immunity-1 Latin word Immunitas :Protection from legal prosecution Biological definition: Protection from infectious diseases

3 Edward Jenner (1796)

4 The scientific view of immunity = Edward Jenner (1796) Observation Milkmaids generally get No smallpox Hypothesis = Pus from vaccinia (cowpox) Protect milkmaids from smallpox

5 The Origin of Immune Concept-II The concept of Immunity developed gradually through many scientific findings: Robert Koch (1905 Nobel Laureate) :Infectious diseases caused by microorganisms Louis Pasteur :Vaccines against cholera & rabies

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8 These clinical successes facilitate The search of underlying mechanism of Protection of Infectious Diseases The development of Immunology Advances in technology (e.g. Cell culture, Monoclonal Ab, Flow cytometry, Genetic engineering etc) have facilitated our understanding of the immune system and its functions.

9 Non-specific defense mechanism It is an inherent resistant present in the host body they are present as normal components they are not induce by exposure to infection. There are different determinants affected this immunity. :

10 A- host determinant. 1-Age 2-hormones &nutritional 3-Genetic back ground(hereditary factors)

11 B-physical determinate : as membrane barrier,moist surface. Skine; it is first line of defense against infection consisting keratinized outer layer also secretion of sweat,sebaceous, fatty acid, tears.

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13 C-Active antimicrobial determinant: Mucus:it is coats the epithelial cell of mucosa which trapped microbes and remove it with different mechanism: 1-cilia in respiratory tract 2-coughing & sneezing in respiratoy tract 3- flashing reaction of saliva, tears Also skine secretion of sweat & seabessus which is antibacterial & antifungal and mucus membranes of antibacterial &antivirus secreation

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15 Phagocytosis& digestion. Antimicrobial substances of tissue fluids, e.g lysozyme, basic Polypeptides Phagocytosis& digestion. Macrophage:it is either monocytes or Polymorphnuclear leukcytes (PMN) Which are present in peripheral blood or in tissue.

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18 The main function is phagocytosis to ingestion & destroy invades microbes There are variety of molecules which react with many microbes ; 1-Acute phas protein 2-Complement 3 Cytokine

19 Interferon : The important of cytokine in Nonspecific immunity is Interferon(INF) Interferon :It is family of cytokines produced by a wide variety of cell such as fibroblast, macrophage & epithelial cell they induce by viruses that which block the viruses invade from infected neighbear cell of the host.

20 Interferon :

21 Innate immunity First line of defense Penetration of the epithelial surface of the body by microorganism (e.g. bacteria) Engulfment of microorganism by macrophages, neutrophils, and dendritic cells Release of cytokines and chemokines Inflammation

22 Inflammation

23 Adaptive (acquired) immunity Takes time to develop Humoral immunity (antibody mediated specific immunity) Cell-mediated immunity (The aspect of the adaptive immune response where antigen-specific T cell have a main role)

24 Antigen: it is a substance that cause immune response when it introduce into the body of the host, the Antigen have the following character: 1- Have large molecular weight about Dalton or more 2-It should have large surface area.

25 3-It should specificity: this spcificity due to antigenic determinantion (epitopes): which is surface located with certain sequence in sterochemical structure of substance.

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28 4-Chemical complexity :Antigen should have a great degree of complexity,protein are the most potent immunogen because of the three dimention of its structure

29 5-Foreigennes: Antigen must be foreign to the host which it makes contact with it,so it should be recogonized when interoduce into the human or experimental animales

30 Immunogen: it is any substance Foreign to host of immune system there for any microorganism get into the body host and it is foreign into the body host so it is recogonized by cells of immune system and induce the immune response.

31 one must differentiate between antigen which is react(in vitro) with the products of immune system and immunogen which is induce the immune response lead to the production of antibody or T- lymphocyte.

32 Hapten: substance with multi determinants as Allargen molecul can not initiate immune response but react with the product of immune response e.g drugs may adsorbs on surface of R.B.C. stimulating this will result in hemolytic disease and lysis of R.B.C

33 Hapten:

34 Immunological Adjuvant: substance are add to vaccine or antigen to stimulate & enhance theimmune response, Inorganic gell, Alamin salt it the sole adjuvant acceptable for human vaccine.

35 The end