Immune system and immunity
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Immune system and immunity

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by nitish shah

by nitish shah

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Immune system and immunity Immune system and immunity Presentation Transcript

  • THE IMMUNE SYSTEM and IMMUNITY
  • Immune Systeml a biochemical complex that protects the body against pathogenic organisms and other foreign bodies.l The structure, cells and soluble constituents that allow the host to recognize and respond to foreign stimulus.
  • Primary Role of The ImmuneSyateml Surveillance and destruction of substances that are foreign to the body.- bacteria, viruses, parasites or fungi
  • Primary Function of the Immune System1. To protect the body against invasion by so called non-self substance.(any and all substances that are considered “foreign”)2. To differentiate between “self” and “non- self” and to destroy that which is “non- self”
  • Origin, Destination and Structure of the Cells and Tissues
  • Bone Marrowq constitutes almost 5% of the total body weight and is responsible for the formation of all blood cells in adult
  • Stem Cellsq all cells originates from undifferentiated pluripotential hemopoietic stem cells, which can be found first in the mammalian embryo with in the liver then the spleen.q are pluripotential CD34+
  • l Erythropoiesis q occurs when a CFU-S cell gives rise to burst-forming units-erythrocytesl granulocytopoiesis q the generation of three types of granulocytesl monocytes q more pathogenic than neutrophils or eosinophils
  • Dendritic Cellsq are bone marrow derived cells specialized for presenting antigens to either CD4+ or CD8+ t cells in order to initiate a primary immune response.
  • Thymusq is a primary lymphoid organ that is required for the generation of immunocompetent CD3+4+ & CD3+8+ cells necessary for an adaptive immune response.
  • Lymph Nodesq are encapsulated structures that are strategically placed throughout the body to receive and filter antigens & cells from peripheral interstitial fluid and lymph.
  • Localization of Cells1.Superficial cortex q containing primary & secondary follicles with germinal centers containing dark and light zone2. Deep cortex q containing high endothelial post-capillary venules3. Medulla q with medullary cortex
  • Spleenl is an encapsulated organ with lymphoid tissue called white pulp(WP), which can respond to blood-borne antigens surrounded by the red pulp(RP).l Mucosal Associated Lymphoid Tissue (MALT)
  • T Cellsl about half of the stem cells migrates to the thymus gland where they differentiate into T lymphocytes or T cellsl small lymphocytes found in the bloodl about 70%-80% of the lymphocytes in peripheral blood are T cells.
  • Two immunologic Functions of T cells1. Effector q includes the cytolysis of virally infected cells & tumor targets & the production of lymphokines2. Regulator q includes the ability to amplify or suppress other effector lymphocytes
  • Most of the T-cells express three of the following CD Markersl CD2l CD3l CD4l CD8
  • Two Subpopulation of T cell in the Circulation1. Those with CD2, CD3, CD4 phenotype2. Those withCD2 ,CD3, CD8 phenotype
  • includes: 1. Helper T cells (Th cells) 2. Suppressor T cells ( Ts cells) 3. Cytotoxic T cells (Tc cells ) 4. Delayed hypersensitivity T cells (Td cells)
  • B cellsl Other lymphocytic stem cells differentiate in the liver & intestinal lymphoid areas into B lymphocytes or B cells.l About 10%-15% of the lymphocytes in peripheral blood are B cells.l Each is capable of producing hundreds of specific antibodies per second
  • IMMUNITYin positive sense: q providing natural resistance, recovery, and acquired resistance to infectious disease.in negative sense: q may result in rejection of a life-saving transplant
  • Types of Immunity
  • Natural or Innateq present at the time of birth or that develops during maturation
  • - refers to anatomical, cellular, and humoral defenses that function in the early stages of host defense response to foreign substances (antigens)- cells that function in innate immunity does not possess immunological memory.- they are nonspecific because the cells do not express receptors specific to one particular antigen.
  • Acquired or Adaptiveq which is acquired as a result of prior experience with a foreign substance
  • Further divided into:humoral immunity (gut associated tissue GALT) q is mediated by the antibody secreted by terminally differentiated B cells, the plasma cells q Type I, II, III hypersensitivity reactionsCell mediated immunity (Thymus) q involves T cells that recognize antigen in an MHC- restricted fashion (CD4 - T-helper cells, CD8 - T-suppressor cells) q tissue graft rejection, delayed hypersensitivity reaction, mononuclear inflammatory reaction
  • Characteristic of Natural Immunity1. Do not possess immunologic memory2. Non specific • operates as the first line of defense against pathogens includes the Physical barriers: – Skin – Mucous membrane – Susceptibility & nonsusceptibility – The provision of an unfavorable environment for the infecting organism
  • Host defense in Innate Immunity1. Cells q antigen presenting cells q basophils q eosinophils mast cells natural killer cells phagocytes2. Humoral Factors q complement proteins q lactoferrin (present in tears, sebaceous & sweat glands) q lysozymes
  • 3. Anatomical Barriers q cilia q mucus membrane q skin4. Resident Flora q mainly nonpathogenic bacteria q prevents colonization of new microorganisms. (intestine, vagina & nasopharynx)
  • Other factors that forms theoverall action of innate immunity1. Inflammation2. Complement3. Phagocytosis
  • Adaptive immunity1. Acquired adaptive immunity q is highly specific, inducible, discriminating & unforgetting. - cell surface receptors are specific for a particular antigen. - memory because lymphocytes that have been activated in response to a particular antigen will respond much faster in a subsequent exposure to the same antigen. q T lymphocyte dependent response.
  • TwoTypes of Adaptive immunity1. Acquired active immunity q by actual infection or inoculation that causes the production of specific protective antibodies (vacines - hepatitis, tetanus)2. Acquired passive immunity q afford temporary protection against invading antigen. (RhIg given during birth, HBIg)
  • Characteristic of Adaptive Immunity1. With Memory2. Specific
  • Host Defense in Adaptive immunity1. Cells q B cells q plasma cells q T cells (cytotoxic & helper cells)2. Humoral factors q antibodies q cytokines
  • Factors involved in the degree of infectionl size of infecting dosel route of administrationl type of infective agent
  • Nothing is predestined: The obstacles of your past canbecome the gateways that lead to new beginnings. Thank you and God bless!!!