Acquired (specific ) immunity 4.24.45 PM

Acquired (specific ) immunity 4.24.45 PM - ‫بسم...

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Unformatted text preview: ‫بسم اللة الرحمن‬ ‫الرحيم‬ Acquired Immunity Acquired Immunity Acquired (Adaptive) Immunity Acquired Defensive mechanisms include : 1) Innate immunity (Natural or Non specific) 2) Acquired immunity (Adaptive or Specific) Cell­mediated immunity Humoral immunity Aquired (specific) immunity Aquired * The acquired immune response is more specialized * The than innate immune response * The acquired immune response involves a combination of two mechanisms : 1) Humoral immune response 2) cell mediated immune response * They interact with one another to destroy foreign body (microorganisms, infected cells, tumor cells) Aquired (specific) immunity Aquired Two mechanisms 1) Humoral immune response: ­ Antibodies are produced by B­lymphocytes ­ These have the ability to recognize and bind specifically to antigen that induced their formation 2) The cell mediated immune response (CMI) ­ It is mediated by certain types of T­lymphocytes ­ T­lymphocytes recognize foreign material by means of surface receptors ­ T­lymphocytes attack and destroy foreign material directly or through release of soluble mediators i.e. cytokines Characters Of Acquired Immune Response Characters 1) Highly specific for the invading organism 2) Discrimination between “self and “non self” molecules The response only occurs to “non self” molecules 3) Diversity: ­ It can respond to millions of different antigens ­ Lymphoctes population consists of many different clones (one cell and its progny) ­ Each clone express an antigen receptor and responds only to one antigenic epitope Mechanism Of Acquired Immune Response Mechanism Acquired immune response is initiated by: * Recognition of the antigen by specific lymphocytes * Activation of these specific lymphocytes * Proliferation and differentiation into effector cells; ­The effector cells eliminate the antigen ­Return of homeostasis and development of memory cells * Memory cells evoke a more rapid and long response on re­ exposure to same antigen Acquired Or Adaptive Immunity Acquired I­ Passive acquired immunity a­Naturally passive acquired immunity Antibodies are passed through placenta to the fetus b­ Artificially passive acquired immunity The injection of alredy prepared antibodies, such as gamma globulin (short­term immunization) II- Active acquired immunity IIa­Natural active acquired immunity : ­ Following clinical or subclinical infections ­ measles or mumps, in which immunity is long lasting b­ Artificial active acquired immunity : ­ Following vaccination with live or killed infectious agents or their products Mechanism of Humoral immunity Mechanism * Antibodies induce resistance through: 1) Antitoxin neutralize bacterial toxins (diphtheria,tetanus) Antitoxin are developed actively as a result of: a­ Previous infection b­ Artificial immunization c­ Transferred passively as antiserum * Neutralization of toxin with antitoxin prevents a combination with tissue cells Mechanism of Humoral immunity Mechanism 2) Antibodies attach to the surface of bacteria and a­ act as opsonins and enhance phagocytosisd b­ prevent the adherence of microorganisms to their target cells, e.g. IgA in the gut c­ Activate the complement and lead to bacterial lysis d­ Clump bacteria (agglutination) leading to phagocytosis Vaccination Vaccination * Vaccination prevents and control such diseases as cholera, rabies, poliomyelitis, diphtheria, tetanus, measles, and typhoid fever * Vaccines can be: a­ prophylactic (e.g. to prevent the effects of a future infection by any natural or "wild" pathogen b­ Therapeupic (e.g. vaccines against cancer are also being investigated) Vaccination Vaccination Vaccination: *Producing immunity against pathogens (viruses and bacteria) by the introduction of live, killed, or altered antigens that stimulate the body to produce antibodies against more dangerous forms *Vaccines work with the immune system's ability to recognize and destroy foreign proteins (antigens) Vaccination Vaccination Immunization of young children and adolescents: ­ Hepatitis B (HepB) and Hepatitis A (HepA) ­ Diphtheria, tetanus and pertussis (whooping cough) given together as DTaP (formerly DTP) ­ Haemophilus influenzae b (Hib) ­ Poliomyelitis (IPV) ­ Measles, Mumps, and Rubella, given together as MMR ­ Chicken pox (Var) Cells Of Immune Response Cells Cells involved in specific immune mechanisms are: I) Hematopoitic leucocytes 1­ Lymphoid * T­lymphocytes: ­ Antigen specific cells carrying CD3 complex, CD4, CD8 ­ Dominant blood lymphocytes (70%) ­ Produce cytokines ­ Activation of other cells (Th CD4) ­ Suppressors for others (Ts CD8) Cells Of Immune Response Cells * B­lymphocytes: ­ Antigen specific cells with surface receptor ­ Less common lymphocytes (20%) ­ Responsible for antibody production * NK, K cells: ­ Not antigen specific ­ Carry Fc receptors , NK­target cell receptor Cells of Immune Response (cont.) Cells 2­ Monocytic myeloid a­ Monocyte­tissue macrophages: . Non specific . Carry Fc receptors . Phagocytic . Antigen processing and presenting cells . Produce cytokines b­ Neutrophils: . Non specific . Carrying Fc, complement molecules Cells of Immune Response (cont.) Cells c­ Eosinophils: . Non specific . Carrying Fc receptor . Produce allergic mediators d­ Basophils and Mast cells: . Non specifc . Carrying Fc receptors . Produce allergic mediators Cells of Immune Response (cont.) Cells ІІ­Non hematopoietic cells: ­ Dentritic cells ­ Astrocytes and ­ Endothelial cells Function : antigen presentation Thanks Thanks ...
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This note was uploaded on 12/24/2011 for the course STEP 1 taught by Professor Dr.aslam during the Fall '11 term at Montgomery College.

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