3.  Bacteria  Fungi  Viruses  Parasites  Protozoa  Auto-immunity ?  Malignancy ?

4.  Innate system ( “old school”Castle with infantry defending )  - Castle : skin and mucous membrane  -infantry ( phagocytes )  Adaptive system (“modern “ intelligence gathering, IT and guided missiles and smart bombs)

6. External epithelia: External surface Wounds & abrasions Insect bites Mucosal surfaces: Airway Gastrointestinal tract Reproductive tract (Fig. 2.2)

10.  Mucosa associated lymphoid tissue  80% of all immune cells  3 functions :  Protect mucous membranes  Prevent uptake of foreign antigens from food  Prevent pathological responses if foreign antigens cross the mucous membrane

13.  then the innate immune response begins.  The cells of the immune system determine “self” from “non- self” by recognizing molecules on the microbe surface.  Macrophages and dendritic cells are immune cells (phagocytes) that reside within the tissue. Neutrophils are phagocytes that reside in the blood but can extravagate into tissue during inflammation.  There are circulating proteins, called complement, that either kill microbes or mark them for effective phagocytization.

15. Complement is a system of plasma proteins that interacts with pathogens to mark them for destruction. 1. Alternative pathway : pathogen surfaces 2. Mannan binding-lectin pathway : lectin binding to pathogen surfaces 3. Classical pathway : Ag:Ab complexes Functions: phagocytosis inflammation lysis

16.  Through pattern recognition ( genetically programmed )  PAMPS  Toll like receptors

17.    Activates vascular endothelium  Activates lymphocytes  Local tissue destruction  Increases access of effector cells    Fever,  production of IL-6

18.    Activates vascular endothelium  Increases vascular permeability    Increased entry of IgG, complement, and cells to tissues  Increased fluid drainage to lymph nodes    Fever  Mobilization of metabolites  Shock

19.    Lymphocyte activation  Increased antibody production    Fever  Induces acute-phase protein production

20.    Activates NK cells  Induces the differentiation of CD4 T cells into T H 1 cells

24.  Hypothalamus  increased body temperature  Fat, muscle  protein & energy mobilization to allow increased body temperature   decreased viral & bacterial replication &  increased antigen processing & specific immune response

28. Antigen specific response to antigen / pathogen Key feature if this system is that subsequent exposure to the initial antigen leads to more rapid and vigorous response ( Immunological memory) T and B lymphocytes drive this response from common stem cell

29.  T-cell : cellular immunity through differentiation in TH-1 ( cellular )and TH-2 pathways ( humoral)  B-cell clonal response initially producing IgM and then IgG to infections : Memory cells produced that react much faster to future threats from the same pathogen.

33.  Positive and negative selection of t-cells  CD-4, CD-8 and T-killer cells emerge  Thymus continues to work in adult life especially when t-cell pool is damages as in AIDS and cancer chemotherapy

34.  4 Major components :  Humoral immunity  Cell mediated immunity : lymphocytes  Phagocyts and polymorphnuclear cells  Complement