Innate and Adaptive Immunology PDF

Innate & Adaptive Immunology Assoc. Prof. Dr Rajesh Ramasamy Immunology Unit Department of Pathology Faculty Of Medicine And Health Sciences Universiti Putra Malaysia NUR3107 Basic Microbiology, Immunology and Parasitology Functions of the Immune System A state of protection from infectious dise...

Innate & Adaptive Immunology Assoc. Prof. Dr Rajesh Ramasamy Immunology Unit Department of Pathology Faculty Of Medicine And Health Sciences Universiti Putra Malaysia NUR3107 Basic Microbiology, Immunology and Parasitology Functions of the Immune System A state of protection from infectious disease Non-specific and specific Non-specific immunity Innate immunity Inherited or naturally occurring defence First line body defence system Specific immunity - Adaptive immunity - High degree of specificity to a particular pathogens - Immunological memory  Range of harmful organisms VIRUS Infectious organisms HELMINTHS  Distribution of immune cells Circulatory System Lymphatic System Barriers to Infection: Immunological Protection Innate system Antigen presenting cells Adaptive system Innate-adaptive Cellular barrier Secretion fluid: tears, saliva, mucous, digestive fluid, interstitial fluid, serum pH: acidic, alkaline Physiological barrier mucous membrane and cilia Skin and hair Anatomical / Physical barrier Virus Bacteria Protozoa Fungi Helmint Macrophages Cellular components Macrophages / monocytes important cell type in innate immunity found in most tissues as local macrophages act as police, leave bloodstream patrol and sample the tissue for foreign invaders and back to bloodstream by lymphatic system. Function Phagocyte pathogens or damaged tissues ( sampling) Produce danger signals (cytokines and chemokines) if there is infection this will induce inflammation cascade (vasodilatation, chemo-attractant , accumulation of more macrophages and PMN) Process involved in elimination of pathogen - chemotaxis - phagocytosis - killing 1. Chemotaxis 2. Phagocytosis agents that induce cell engulfment of pathogens by phagocytes migration ( chemokines or formation of pseudopodia and can be pathogens products such as enhanced by opsonin such as complement or fMLP) receptors Phagocytes migrate toward an increased gradient of chemoattractant 3. Microbial killing elimination of pathogens by hydrolytic enzymes or reactive oxygen species (ROS) Mechanisms to clear pathogens NK cell mediated lysis Upon recognition of antigen through activatory receptor, NK cell produces Perforin Granzymes Perforin makes holes in the target cells Granzymes activate apoptosis Image adapted from https://www.pinterest.co.kr/pin/442126888393962511 Adaptive Immune Cells  Lymphocytes - B and T cells - main players of the immune system - priming, proliferation and effector function  APC - Dendritic cells and Macrophages - initiator of immune response T cells  Derived from BM and educated in thymus  In the thymus, T cells that express a single specific T cell receptor mature and are released to circulation  Device that recognises foreign antigens called TCR  Cell mediated immune response, T helper and T cytotoxic B cells ▪ Derived and matured in BM ▪ Device that recognises foreign antigens called as B cell receptor (BCR) or Antibody ▪ Humoral immunity  A protein or oligosaccharide marker on the surface of cells  Identifies the cell as self or non-self  Stimulates the production of antibodies, by B lymphocytes, that will neutralize or destroy the cell if necessary  stimulates cytotoxic responses by granulocytes, monocytes, and lymphocytes  Medically important antigens Allergens Self-proteins Transplant proteins Tumour antigens Cells of Immune System Adaptive Immune Cells T cells CD4+ T cells CD8+ T cells B cells T and B Cells Adaptive Immune Cells Produced in the bone marrow in postnatal life from haematopoietic stem cells Lymphocytes (T & B Cells) derived from common lymphoid progenitor cells B and T cells mature in bone marrow and thymus, respectively Maturation process is mandatory for forming antigen specific receptors (BCR & TCR) on lymphocytes BCR: B cell receptor / Immunoglobulin / antibody TCR: T cell receptors Functional of Adaptive Immune Cells Functions of adaptive immune cells Clearance of pathogens from the body (B cells) Strengthening the cellular immunity by secretion of pro-inflammatory cytokines (CD4+ Th1 cells) Clearance of infected cells or transformed cells (cancer cells) (CD8+ Cytotoxic T cells) Adaptive Immune Response Adaptive Immune Response Lymphocytes require antigen recognition, activation, expansion (proliferation) in order to become effector cells Effector cells are fully activated immune cells which are ready to perform their duties Antibody producing B cells, cytokines secreting T helper cells and cytotoxic T cells that kill infected target cells Once the inflammation is over, activated lymphocytes will undergo apoptosis leaving a small fraction of memory cells Effector mechanism of CTL Humoral Immunity Immunity to Extracellular Bacteria Immune response towards intracellular bacteria Immunity towards virus  References IMMUNOBIOLOGY, 6TH EDITION, KUBY IMMUNOLOGY, 6TH IMMUNOLOGY, 2ND EDITION, JANEWAY ET AL. 2005 EDITION, KINDT ET AL. 2007 KLAUS D. ELGERT, 2009 Note: The images and media used in the presentation as full or partial were taken from the published sources. The primary resources were either indicated in the relevant slides or at the reference slide. Thus, these should be used for personal (academic) use only and strictly not for dissemination or public use.