a full detailed illustration of INNATE & ADAPTIVE IMMUNITY & its COMPONENTS (NK cells, phagocytosis, APCs, Active & Passive immunity)

1. Innate and Adaptive
In detail
Immune system
@ujjwal sirohi
Ph.D scholar

2. content
 Innate immune system
 Mechanism of phagocytosis
 Inflammatory response
 Natural killer cells
 Events of inflammation
 Adaptive defense
 Adaptive, Humoral Immunity
 Antigen Presenting Cells (APCs)
 Types ofAcquired Immunity

4. Innate immune system
 Innate structural defenses: respond to non-specific foreign
substances.
 First line: external structure epithelium & membranes
 Second line: inflammatory processes- anti-microbial proteins,
phagocytes, etc

5. Innate: surface defence
 Skin
o physical barrier to microbes
o Keratin resistant to most bacterial enzymes and toxins
o Secretions are acidic pH 3-5
• Mucous
o Physical barrier and produces a variety of products
• Gastric mucosa
o Very acidic and produces, proteolytic enzymes
• Saliva and lacrimal fluid contain lysozymes
• Mucous
o Traps bacteria and moves them away from epithelial surface

6. Innate internal defense
 Phagocytes
◦ Macrophages: derived from monocytes
 Free Macrophages: roam through tissues
 Fixed Macrophages: Kupffer cells (liver) & microglia (brain)
 Ingest cellular debris, foreign material, bacteria, fungi
◦ Neutrophils: ingest pathogens
◦ Eosinophils: weakly phagocytic of pathogens.Attack parasites
(degranulation)
◦ Mast Cells: phagocytic of various bacteria

7.  Phagocytic mechanisms:
◦ Adherence: cell binds to invader
 Aided by opsonization (a chemical process that enhances binding via
complement & antibodies)
◦ Ingestion: formation of phagolysosomes
 Respiratory Bursts: merge phagosome with lysosome & flood
phagolysosome with free radicals (macrophage)
 Defensins: proteins that crystallize out of solution & pierce pathogen
membranes (neutrophils)

8. Mechanism of phagocytosis

9. Natural killer cells
 A population of lymphocytes that recognises components
associated with pathogens,or stress and generates rapid protective
responses.
 NK cells are preprogrammed to respond to immadiately to
appropriate stimuli.
 NK cells secreates cytokines-the proinflammatory cytokines IL-6
&TNF-α as well asType I INFs & theType II IFN,IFN-γ a potend
macrophage activator that also help to activate and shape the
adaptive response.
 Release chemicals that enhance the inflammatory response
 Not phagocytic: attack is by release of perforins that
perforate the target cell plasma membrane.

10. Inflammatory response
 Tissue response to injury
 Triggered by injury – trauma, heat, chemical irritation, infection,
etc.
 Beneficial effects
 Prevents spread of injury
 Disposes of cellular debris & pathogens
 Promotes repair
 cardinal signs of inflammation
 Redness
 Heat
 Swelling
 Pain
 (functional impairment Rigor)

11. Events of inflammation

12. Events of inflammation

13. Adaptive defense

14. Adaptive Defenses: Characteristics
 Specificity: directed at specific targets
 Systemic: not restricted to initial site of infection / invasion
 Memory: after initial exposure & activation, a more rapid &
more vigorous response is made to subsequent exposures to
pathogen(secondary response)

15. Adaptive Defenses: Components
 Humoral Immunity: (antibody mediated immunity)
provided by antibodies floating free in body fluids
 Cell mediated immunity:
 lymphocytes directly attack specific invaders by lysis or indirect
attack by initiating inflammation and/or activating other
lymphocytes & macrophages

16. antigen
 Antigen = any substance that can mobilize the immune system &
provoke an immune response (Humoral and/or cell mediated).
 Substances that can be recognised by the immunoglobulin receptor
of B cells, or theTcell receptor when complexed with MHC, are
calles antigens.
 Although substances that induce a specific immune response is
more specifically called an immunogen.
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17. Adaptive, Humoral Immunity
 Complete antigens (proteins, nucleic acids, lipids,
polysaccharides):
 Immunogenicity: the ability to stimulate specific lymphocytes &
specific antibodies
 Reactivity: the ability to react with activated lymphocytes &
antibodies
 Hapten (an incomplete antigen): a smaller molecule that is
not immunogenic until attached to proteins

18. Adaptive, Humoral Immunity
 Antigenic determinants: sites on an antigenic molecule that are
immunogenic
 Epitope
 Major Histocompatibility Complex (MHC): cell surface
glycoproteins associated with self recognition

19. Adaptive Immune System: Cells
 Lymphocytes
 T-cells
 B-cells
 Antigen Presenting Cells (APCs)

20. Adaptive Immune System: Cells
 Lymphocytes: initially uncommitted
 T-cells: are sorted in theThymus
 Positive selection: recognize MHC survive
 Negative selection: react against to self-antigens on MHC killed
 2% of initialT-cell precursors
 T-cells manage the immune response
 B-cells: are sorted in the marrow by an incompletely understood process

21. Adaptive Immune System: Cells
 Immunocompetence: asT- or B-cells mature they become
immunocompetent, they display receptors on their cell
membrane for a specific antigen.
 All of the receptors on one cell are identical; immunity
depends upon genetic coding for appropriate receptors.

22. Adaptive Immune System: Cells
 Antigen Presenting Cells (APCs)
 APCs ingest foreign material, then present antigenic
fragments on their cell surface where they are recognized by
T-cells
 T-cells: respond to antigen only if it is displayed on plasma membrane.
 APCs: Macrophages & B lymphocytes
 Interactions betweenAPCs & lymphocytes & lymphocyte-
lymphocyte interactions are critical to immune response

23. Adaptive, Humoral response
 Humoral response (clonal selection)
 B-cells:Antigen challenge to naïve immunocompetent B-cell
 Antigen binds to B-cell receptors & form cross-links between
receptors
 Cross linked antigen-receptor complex undergoes
endocytosis; B-cell presents toT-cell

25. Humoral Immunity
 Active humoral immunity:
 B-cells encounter & respond to antigen to produce an antibody
 Passive humoral immunity:
 Introduced “non-native” antibody

26. Active Humoral Immunity
 Naturally acquired: natural exposure to antigen (i.e.
infection)
 Artificially acquired: vaccines; dead/attenuated or
fragmented pathogen injected to elicit an immune response
 Bestow immunity without disease; primary response
 Booster shots (secondary response); intensify response
 Shortcomings – adverse reactions & the immunity is less durable (poor
memory) & has less cell mediated component

27. Passive Humoral Immunity
 Natural: maternal antibody crosses the placental barrier
conferring temporary immunity to the baby (degrades after a
few months)
 Artificial: antibodies harvested from an outside source given
by injection protect from immediate threat but no memory is
formed (antitoxins, antivenins , gamma globulin, etc.)

28. Types of Acquired Immunity

29. Overview of humoral and cell mediated
immunity

30. Major Types of T Cells

31. Summary of the Primary Immune Response

32. Presented by@ujjwal sirohi
Ph.D scholar
Thank you