Definition,Properties,Components,Barriers.

1. D.JYOTI
135040
ZOM 602

2. Definition: Innate
Immunity
No need for prolonged induction.
•No clonal expansion of Ag specificity.
•Act quickly
•Immediate direct response 0-4 hours
•Rapid induced 4-96 hours
•Failure ==> adaptive immune response.
•Dependence on germ line encoded
receptors.
•High discrimination of host and pathogen.

3. Innate Immunity
First line of
defense
Intact skin
Mucous
membranes &
their
secretions
Normal
microbiota
Second line
of defense
Phagocytes, such as
neutrohils,eosinophiles,dendritic cells,
macrophages
Inflammation
Fever
Antimicrobial
substances

6. Components

10. How innate immunity
protects?
Provides a barrier to prevent the spread
of infection
•Mechanical (tight junctions, movement)
•Chemical (fatty acids, enzymes, pH,
antimicrobial peptides)
•Microbiological (normal flora)
•Mucosal surfaces
•Nasopharyngeal, Oral, Respiratory, Intestinal
tract ,urogenital tract
 Skin (epithelial cells)
•Wounds, burns, insect bites

11. Identifies and eliminates pathogens.
 Initiates an inflammatory response
•Reaction to injury or infection
• Trauma to tissues or cells.
• Presence of foreign matter (self vs. non-
self)
• Infectious agents (viruses, bacteria,
fungi)
 Delivers effector molecules & immune
cells to the site of infection
•Components
•Leukocytes & secreted factors
•Blood vessels

12. Phagocytosis

13.  Cytokines
 Induce response by binding to specific receptors
 Can function in autocrine or paracrine manner
 Cytokines (and their receptors) are clustered
according to structural similarities
 Critical cytokines secreted by macrophages following
activation include TNFA, IL-1, IL-6, IL-12 to stimulate
inflammation and phagocytosis/killing
 Chemokines
 Diverse family of chemotactic cytokines, induce
directed chemotaxis of cells
 All related in amino acid structure
 Certain chemokines induce cell activation in addition
to cell recruitment
 Promiscuous in receptor usage, each can bind more
than one receptor
 Likewise, receptors are promiscuous

14. The role of NK cells

15. Interferon
 Defense against viral infections
 Cytokine produced & released by host cells
invaded by virus
 Prevents virus from infecting healthy cell
 Stimulates uninfected cells to produce antiviral
proteins
 INF- & INF- are anti-inflammatory.
 INF- is proinflammatory and enhances cell-
mediated immunity

17. 2011 Nobel Prize in Physiology
or Medicine
 The 2011 Nobel Prize in
Physiology or Medicine was
awarded to Bruce Beutler at
the Scripps Research
Institute in California, Jules
Hoffmann at the French
National Center for
Scientific Research and
Ralph Steinman at The
Rockefeller University in
New York City.
 Beutler and Hoffman helped
to elucidate innate
immunity, the non-specific
array of initial responses by
the body’s immune system
that can recognize invading

18. The current knowledge helps
for newer vaccine trends
The detailed understanding
of the immune system
provided by the new Nobel
laureates has given other
researchers the ability to
improve vaccines and to
attempt to stimulate immune
reactions to cancer.
Their insights also inform
efforts to damp down the
immune system when it
becomes too zealous, which
can lead to excessive
inflammation and
autoimmunity.