D.JYOTI135040

ZOM 602

INNATE IMMUNI

TY

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.

Innate ImmunityFirst line

of defense

Intact skin

Mucous membranes & their secretion

s Normal

microbiota

Second line of

defensePhagocytes, such as

neutrohils,eosinophiles,dendritic cells, macrophages

Inflammation

Fever

Antimicrobial

substances

PROPERTIES OF INNATE IMMUNITY

First line of defense

Cell mediated immunity

React predominantly to infectious agents

Stimulate and shape adaptive immunity

Immediately react after contact with pathogen.

No long lasting memory.

Components• Skin• Mucous membrane

Epithelial Barriers

• Phagocytes• NK cells• Macrophages• Dendritic cells

Cells

• Compliment • Cytokines

Humoral compone

nts

Anatomic Barrier

Physiologic barrier

Phagocytic barrier

Inflammatory Barrier

• Skin • Mucous membrane

• Temperature• pH• Chemical Mediators

BARRIERS OF INNATE IMMUNITY

Leukocyte Players of Innate Immune Responses

What happen when physical and chemical barriers are breached?

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

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

•Plasma proteins

Phagocytosis

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

ChemokinesDiverse 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

The role of NK cells

InterferonDefense 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

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 microorganisms as being foreign and try to destroy them. and the other half to Ralph M. Steinman "for his discovery of the dendritic cell and its role in adaptive immunity".

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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.

THANK YOU