The document summarizes innate immunity. It describes innate immunity as the non-specific first line of defense against infection found in all living organisms. This includes anatomical barriers like skin and mucous membranes, chemical inhibitors like stomach acid, and microbial flora. The second line of innate immune defense includes natural killer cells and phagocytes that attack pathogens. Soluble factors like complement proteins and cytokines also help innate immunity, as does the inflammatory response to infection and tissue damage.

1. INNATE
IMMUNITY
Presented By:
Preety Sweta Hembrom
Subject- Immunology
M.Sc. Genomic Science
Central University Of Kerala

2. 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.

3. 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.

4. CONTD…
 The mechanism of immunity can be achieved by
two types of immune response:
1. Cell- mediated immune response
2. Humoral immune response

6. COMPONENTS OF IMMUNITY:
 Contains two major components:
1. Innate Immunity (Non-specific)
2. Adaptive Immunity (Specific)

7. Innate ImmunIty

8. 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.

9. DEFENSIVE BARRIERS OF INNATE
IMMUNITY:
Innate Immune system
First line Second
line
1) Anatomic barriers A) cells
2) Chemical & biochemical inhibitors 1- Natural
killer
3) Normal flora 2-
Phagocytes
B) Soluble
factors
C) Inflammatory

10. FIRST LINE:
1) Anatomic barriers:
 Intact skin
 Mucous coat
 Mucous secretion
 Blinking reflex and tears
 The hair at the nares
 Coughing and sneezing reflex

11. 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

12. CONTD:
3) Normal bacterial flora:
 Competition for essential nutrients
 Production of inhibitory substances

13. 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.

14. FUNCTIONS:
 Cytolytic Granule Mediated Cell Apoptosis.
 Antibody-Dependent Cell-Mediated Cytotoxicity
(ADCC).
 Cytokine induced NK and CTL activation
 Tumor cell surveillance

16. Immune System - Natural Killer Cell.mp4

17. 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, de
ndritic cells, and mast cells.

18. 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.

19. CONTD:
II. Ingestion:
* Phagocyte pseudopodia surround
organism forming phagosome.
* Opsonin and co-factors enhance
phagocytosis.
* Fusion with phagocyte granules and release
digestive, toxic contents

20. CONTD:
III. Killing :
 Digestion and killing by Lysozyme.

22. 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)

23. 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.

25. The Inflammatory Response.mp4