3Terminology Types of Symbiosis ( Living togathers) - Amensalism A symbiotic relationship in which one species is harmed, but it isdifficult to see how the other species benefit.MutualismA symbiotic relationship in which both species benefitCommensalismA symbiotic relationship in which one species benefits, and the other species is neither helped nor harmed
4Types of Symbiosis (cont.) ParasitismA symbiotic relationship in which one species benefits, and the other species is harmedGenerally, the species that benefits (the parasite) is much smaller than the species that is harmed (the host)
5Disease and Infectious Disease Any deviation from a condition of good health and well-beingInfectious DiseaseA disease condition caused by the presence or growth of infectious microorganisms or parasites
6Immunology lingo Antigen Pathogen Antibody (Ab) Immunoglobulin (Ig) Any molecule that binds to immunoglobulin or T cell receptorPathogenMicroorganism that can cause diseaseAntibody (Ab)Secreted immunoglobulinImmunoglobulin (Ig)A glycoprotein produced in response to the introduction of an antigenVaccinationDeliberate induction of protective immunity to a pathogenImmunizationThe ability to resist infection
7TYPES OF IMMUNITY.Nonspecific: Skin and mucous membranes, Phagocytosis, Inflammation, and The Complement System.Specific: Humoral(Antibody-Mediated) and Cell-Mediated.
8Nonspecific Immune Response Physical and Mechanical Barrier’sChemical Factor’sBiological Factor’sPhagocytosis and Associated with Blood and lymphDefenses that protect from ANY pathogen regardless of type and species( Bacteria, Fungi, Protozoa, etc).
9Physical and Mechanical Barrier’s THE SKIN: First Line Of Defense.Repels many organisms: difficult to get through.Epithelium lines all body systems exposed to external environments including the respiratory, digestive and urinary systems.Secretes liquid which are mildly acidic which hinder bacterial growth.Lack of nutrition for microbial growth.
16Flushing Mechanisms Epiglottis. Urine and Vaginal secretions. Sneezing, coughing, swallowing reflexMovement of Fluids across their surfaces (Saliva)Washing action of tears
17CHEMICAL FACTORS.Sebum and fatty acids in skin ( e.g. unsaturated fatty acids as Olic acid).Gastric Juice (Low pH stomach ).Lyzozyme: degrade the bacterial cell wallAntimicrobial peptides (β Lysine) with high quantity of Lysine or Arginine. Act by disruption of plasma membrane of microorganisms.
18Complement:complex of 17 proteins (Glycoproteins) present in normal serum) C1, C2, C3 …..etc. Function: Lysis of microbes, Neutralization of viruses, Enhancement of phagocytosis, Damage of plasma membrane, Recruitment of Phagocytes,Interferons : Family of Glycoproteins that block Viral Replication by rendering host cells,
19NORMAL MICRIBIOTA AND NONSPECIFIC RESISTANCE. Microbial Antagonism.Commensalism.Competitive Exclusion: Opportunistic pathogens.Natural Resistance: Microorganisms has a host range
20Cells of the Immune system: FORMED ELEMENTS IN BLOOD. Many cells of the immune system derived from the bone marrowHematopoetic stem cell differentiation
21Components of blood Serum vs. Plasma Serum: cell-free liquid, minus the clotting factorsPlasma: cell-free liquid with clotting factors in solution (must use an anticoagulant)Contain protein: Albumin, Globulin and Fibrinogen.
23LEUKOCYTES.Divided into two main categories based on their appearance under the light microscope:Granulocytes Versus Agranulocytes.Granulocytes: Neutrophils(stain lilac), Basophils (stain blue-purple), and Eosinophils (stain red or orange).
24NEUTROPHILS ( 60% of WBC)Commonly called polymorphonuclear leukocytes (PMNs).Multinucleated.Highly phagocytic and motile.Active in the initial stages of infection.Short life span (hours)Very important at “clearing” bacterial infectionsInnate Immunity
25BASOPHILS (1% of WBC) Role is not clear. Release substances, such as histamine, that are important in inflammation.Might be “blood Mast cells’Important in allergic reactions
26Eosinophils ( 3% of WBC) Somewhat phagocytic. Have the ability to leave the blood.Major function is to produce toxic proteins against certain parasites such as worms.Involved in allergic inflammationDouble Lobed nucleusOrange granules contain toxic compounds
27AGRANULOCYTES. Monocytes ( 5% of all WBC). Macrophages. Lymphocytes ( 30% of all WBC) .
28MONOCYTES. Phagocytosis and killing of microorganisms Activation of T cells and initation of immune responseMonocyte is a young macrophage in bloodThere are tissue-specific macrophagesAntigen Presentation
29MACROPHAGES.Maturation and proliferation of is one factor that is responsible for the swelling of lymph nodes during an infection.
30Lymphocytes Many types: B-cells produce antibodies( Humoral immunity) T- cells (Cellular immunity)Cytotoxic T cellsHelper T cellsMemory cells
31Lymphocytes Plasma Cell (in tissue) Natural Killer cells Fully differentiaited B cells, secretes AbNatural Killer cellsKills cells infected with certain virusesBoth innate and adaptiveAntigen presentation
33TH cells play a central role in the immune system AntigenPresentingCell
34Dendritic Cells Activation of T cells and initiate adaptive immunity Found mainly in lymphoid tissueFunction as Antigen Presenting Cells (APC)Most potent stimulator of T-cell response
35Mast Cells Expulsion of parasites through release of granules Histamine, leukotrienes, chemokines, cytokinesAlso involved in allergic responses
36Other Blood Cells Megakaryocyte Erythrocyte Platelet formation Wound repairErythrocyteOxygen transport
37Cells, tissues and organs of the immune system Immune cells are bone marrow-derived, & distributed through out the bodyPrimary lymphoid organs:Thymus: T cell maturationBone marrow (bursa of Fabricius in birds): B cell maturationSecondary lymphoid organs:Lymph nodesSpleenMucosal lymphoid tissues (lung, gut)
43ACTION OF PHAGOCYTIC CELLS. Wandering macrophages.Fixed macrophages.Mononuclear phagocytic (reticuloendothelial) system.During the initial infection, granulocytes, especially neutrophils are many and they dominate.
44Opsonization.Opsonization - coating micro-organisms with plasma proteins – aids phagocytosis.Complement binds to antibody-antigen targets.Promotes adhesion between opsonized cell & macrophages.Opsonin binds to receptors on phagocyte membrane.
46PHAGOCYTOSIS: 2ND LINE OF DEFENSE. Cell Eating.Phagocytes: Cells that perform phagocytosis.Are mostly types of white blood cells or derivatives of white blood cells.
47THE MECHANISM OF PHAGOCYTOSIS. Chemotaxis.Adherence.Ingestion.Digestion.
483. Phagocytosis & oxidative burst. Certain WBCs - phagocytosis.Chemotactically attracted to disease / tissue damage foci.Stages:Engulfment of particulate matter into phagosome. (e.g. bacteria, virions, cell debris, etc.).Phagosome fuses with lysosomes = phagolysosome.
493. Phagocytosis & oxadative burst. Human macrophage engulfing the fungus Candida albicans.Lysosomes contain enzymes = degrade biomolecules.E.g. acid hydrolases, lysozyme, neutral proteases, myeloperoxidase, lactoferrin, & phospholipase A.
503. Phagocytosis & oxidative burst. Engulfed organisms killed in WBC by “respiratory (oxidative) burst".Many pathogens / parasites succeed because avoid phagocytosis.NeutrophilYeastHuman neutrophil kills yeast cell using oxidative burst.Dye shows extent of reactions.
51INFLAMMATION: Second line of defense. Inflammatory response results in increased blood flow to infection; chemical attractants and flow of fluid to wound ( vasodilation).Together these cause swelling, heat, and pain.Fluids include histamine and serotonine (causes arterioles to dilate), and plasma (contains clotting factors to wall off area.
52Kinins: cause vasodilation and increased permeability of blood vessels. Prostaglandins: released by damaged cells, and intensifies the effects of histamin and kinins.Leukotrienes: produced by mast cells and basophils- Cause increased permeability, and attract phagocytes to pathogens.
53Vasodilation and increased permeability of blood vessels also help to deliver clotting elements to injured area.Blood clots prevent microbe from spreading, so a localized collection of pus results(abcess).
54Inflammation.Inflammation - phagocytes & complement recruited to site tissue invasion.Non-specific reaction to tissue damage.Cell damage initiates inflammation.
55Inflammation. Vasodilation - swelling. Adhesion of leukocytes to endothelial cells & migration phagocytes into tissues.Redness (blood flow).Pain (prostaglandins).Heat (pyrogens).Inflammation localised to area infection / injury and give pus.Once organisms destroyed inflammation resolves.
68Actions of antibodies include: NeutralizationAgglutination and precipitationActivation of complementAttraction of phagocytesOpsinizationStimulation of inflammationPrevention of adhesion
69Generation of immune response. Immunogen = any molecule that stimulates immune response. Proteins best immunogens > carbohydrates > nucleic acids. Lipids very poor.Antigen = molecule capable of generating antibody response.Antigen = antibody generating.Haptan= Ag incapable of stimulating immune response. Need carrier molecules for stimulating immune response
70Generation of immune response. ~ 4-7 days to generate immune response.> 7 days get primary immune response.1st IgM produced then IgG.After ~3 weeks primary immune response turned off.Ab producing cells & memory B cells formed.Memory B cells secrete ab when same agent encountered again.This is secondary immune response.Memory lasts weeks / years.
71Classes of Immunoglobulins Large globular glycoproteins released by B cells in the serum of blood tissue fluids and some secretions.Specifically interact with antigens.5 classes Antibodies:1. IgM – largest & 1st Ab made. Neutralisation, fix complement, agglutinate & immobilise ags.2. IgG - main serum Ab. Able to crosses placenta. Synthesized during secondary immune response. All functions. Smallest ab.
72IgA - mucosal / secretory ab , present in mother milk. IgD - receptor ab found on surface immunocompetent cells.IgE - binds surface mast cells = degranulation & histamine release. Allergies.