INNATE IMMUNITY
Presented By:
Preety Sweta Hembrom
Subject- Immunology
M.Sc. Genomic Science
Central University Of Kerala
IMMUNE SYSTEM
The immune system is a system of biological structures and processes within an organism and protects against attacks by foreign invaders.
These invaders are primarily microbes.
The human body provides an ideal environment for many microbes.
IMMUNITY:
Immunity is the state of having sufficient biological defenses to avoid infection, diseases or other unwanted biological invasion.
It is the capability of the body to resist harmful microbes from entering it.
Immunity involves both specific and non-specific components.
CONTD…
The mechanism of immunity can be achieved by two types of immune response:
1. Cell- mediated immune response
2. Humoral immune response
COMPONENTS OF IMMUNITY:
Contains two major components:
1. Innate Immunity (Non-specific)
2. Adaptive Immunity (Specific)
Innate Immunity
INNATE IMMUNITY:
The innate immune system, also known as non-specific immune system.
Innate immune systems provide immediate defense against infection, and are found in all classes of plant and animal life.
DEFENSIVE BARRIERS OF INNATE IMMUNITY:
Innate Immune system
First line Second line1) Anatomic barriers A) cells
2) Chemical & biochemical inhibitors 1- Natural killer
3) Normal flora 2- Phagocytes
B) Soluble factors
C) Inflammatory
barriers
FIRST LINE:1) Anatomic barriers: Intact skin Mucous coat Mucous secretion Blinking reflex and tears The hair at the nares Coughing and sneezing reflex
CONTD:2) Chemical & biochemical inhibitors Sweat and sebaceous secretion Hydrolytic enzymes in saliva HCl of the stomach Proteolytic enzyme in small intestine Lysozyme in tears Acidic pH in the adult vagina
CONTD:3) Normal bacterial flora: Competition for essential nutrients
Production of inhibitory substances
SECOND LINE:
1. CELLS:
a) Natural Killer Cells (NK):
Effectors of innate immunity Cytotoxic lymphocyte Differentiate and mature in the bone
marrow, lymph node, spleen, tonsils and thymus.
FUNCTIONS: Cytolytic Granule Mediated Cell Apoptosis.
Antibody-Dependent Cell-Mediated Cytotoxicity (ADCC).
Cytokine induced NK and CTL activation
Tumor cell surveillance
Immune System - Natural Killer Cell.mp4
CONTD:
b) Phagocytes:
Cells that protect the body by ingesting harmful foreign particles, bacteria, and dead or dying cells.
The professional phagocytes include cells called neutrophils, monocytes, macrophages, dendritic cells, and mast cells.
PHAGOCYTOSIS:
Elle Mechnikov was the first to observe phagocytosis by white blood cells.
I. Chemo taxis & attachment:
a- Attraction by chemo tactic substances
(microbes, damaged tissues)
b- Attachment by receptors( such as TLRs ) on surfaces of phagocytes.
CONTD:
II. Ingestion:
* Phagocyte pseudopodia surround organism forming phagosome.
* Opsonin and co-factors enhance phagocytosis.
* Fusion with phagocyte granules and release digestive, toxic contents
CONTD:
III. Killing :
Digestion and killing by Lysozyme.
2. SOLUBLE FACTORS:
Acute phase protein (Plasma protein, CRP=C reactive protein, Fibrin.)
Complement (proteins in serum, body fluids)
Interferon (Proteins against viral infections)
Properdin (Complement activation) Lactoferrrin, Transferrin (Iron binding
protein) Lactoperoxidase (Saliva & Milk) Lysozyme (Hydrolyze cell wall)
3. INFLAMMATORY BARRIERS: Tissue damage caused by a wound or by an
invading pathogenic microorganism induces a complex sequence of events collectively known as Inflammatory response.
Inflammation is stimulated by chemical factors released by injured cells and serves to establish a physical barrier against the spread of infection, and to promote healing of any damaged tissue following the clearance of pathogens.
Chemical factors produced during inflammation are histamine, bradykinin, serotonin, leukotrienes, and prostaglandins.
The Inflammatory Response.mp4
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