immunology
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IMMUNOLOGY. Cellular and molecular immunology (Abul K. Abbas )7th edition. Application of Immunology. Clinical diagnosis Treatment Prophylaxis Research. Types of immunity. (Natural or Innate immunity) (adaptive or acquired immunity). Innate immunity. First line of defence - PowerPoint PPT PresentationTRANSCRIPT
Innate immunity
• First line of defence• Cellular and biochemical mechanisms are present before
infection• These mechanisms react only to microbes• They respond in essentially the same way to repeated
infections• The principal components of innate immunity are:a) Physical and chemical barriersb) Phagocytic cellsc) Blood proteins(CRP,complement,interferons)d) cytokines
Innate immunity
• Some components are functioning at all times even before infection
• Others are normally inactive but poised to respond rapidly to the microbes
Anatomical Barriers - Mechanical Factors
System or OrganCell typeMechanism
SkinSquamous epitheliumPhysical barrierDesquamation
Mucous Membranes
Non-ciliated epithelium (e.g. GI tract)
Peristalsis
Ciliated epithelium (e.g. respiratory tract)
Mucociliary elevator
Epithelium (e.g. nasopharynx)
Flushing action of tears, saliva, mucus, urine
Anatomical Barriers - Chemical Factors
System or OrganComponentMechanism
SkinSweatAnti-microbial fatty acids
Mucous Membranes
HCl (parietal cells)Tears and saliva
Low pHLysozyme and phospholipase A
Defensins (respiratory & GI tract)
Antimicrobial
Sufactants (lung)Opsonin
Anatomical Barriers - Biological Factors
System or OrganComponentMechanism
Skin and mucous membranes
Normal floraAntimicrobial substancesCompetition for nutrients and colonization
Humoral ComponentsComponentMechanism
ComplementLysis of bacteria and some virusesOpsoninIncrease in vascular permeabilityRecruitment and activation of phagocytic cells
Coagulation system
Increase vascular permeabilityRecruitment of phagocytic cellsΒ-lysin from platelets – a cationic detergent
Lactoferrin and transferrin
Compete with bacteria for iron
LysozymeBreaks down bacterial cell walls
CytokinesVarious effects
Cellular Components
CellFunctions
NeutrophilsPhagocytosis and intracellular killingInflammation and tissue damage
MacrophagesPhagocytosis and intracellular killingExtracellular killing of infected or altered self targetsTissue repairAntigen presentation for specific immune response
NK and LAK cellsKilling of virus-infected and altered self targets
EosinophilsKilling of certain parasites
interferon
• Type I(IFN-α,IFN-β) all immune cells and fibroblasts as an anti virus
• Type II(IFN- )
T cells as a immunoregulator
interferons
• Interferon alphas are used for treating cancers and viral infections
• interferon betas are used for treating multiple sclerosis
• interferon gamma is used for treating chronic granulomatous disease.
Adaptive immunity
• Stimulated by exposure to infectious and noninfectious agents,increase in magnitude and defensive capabilities with each succesive exposure to a particular microbe.
Types of adaptive immunity
• Humoral immunity (antibodies)Principal defence mechanism
against extracellular microbes and their toxins
• Cell mediated immunity (CMI)Defence against intracellular
microbes