Immune system Introduction

1. CAUSSANEL COLLEGE OF ARTS AND SCIENCE
(A unit of the Brothers of the Sacred Heart of Jesus-Palayamkottai)
(Affiliated to Alagappa University, Karaikudi)
Accredited with ‘A’ Grade by NAAC, Recognized by UGC under 2(f) & 12 (B)
Angelo Nagar, Muthupettai – 623523, Ramanathapuram – Dist, Tamil Nadu.
MICROBIOLOGY & IMMUNOLOGY
Department of Biochemistry
Presented By,
Dr.A.Baskara Boopathy
Assistant Professor & Head
Department of Biochemistry
Caussanel College of Arts & Science
Muthupettai, Ramanathapuram.

2. 1] Introduction
2] Immunology Buzzwords
3] Immune Systems
4] Innate and adaptive immunology
5] Organ of immune system
a] Primary lymphoid organ
b] Bone marrow
c] Thymus
d] Secondary lymphoid organ
e] Lymph nodes
f] Spleen
g] Payers patches
h ] MALT,GALT.
CONTENTS

4. Immunology Buzzword :
Antigen:
 Any molecule that binds to immunoglobulin or T cell receptor
Pathogen :
 Microorganism that can cause disease
Antibody (Ab) :
 Secreted immunoglobulin
Immunoglobulin (Ig) :
 Antigen binding molecules of B cells
Immunization:
Vaccination:
 Deliberate induction of protective immunity to a pathogen
 The ability to resist infection

5.  Immunology is a branch of science.
 It deals with the study of immunity and immune systems of all living organisms.
 The process which our body fight against (or) defence from microbes (or) product
from foreign materials like virus, protozoa, fungi etc……..
INTRODUCTION :
THE IMMUNITY:
 The immunity is defined as that it to have ability against pathogen or microbes.
 A self defence mechanism present in human being, to act opposite for pathogens
(unwanted particals)
 Immune Response is defined as to collective and coordinated response to
the introduction of foreign substances in an individual mediated by the cells
IMMUNE RESPONSE :

6. THE IMMUNE SYSTEM FUNCTION :
 Defend and protect the body from infection by bacteria, viruses, fungi and parasites.
 Removing and destroying damaged or dead cells.
 Identifying and destroying malignant cells, thereby preventing their further
development into tumours.
 Immune surveillance
 Immune homeostasis
 Some particular molecules, cells, tissues, gene, organs which are involved to
react against microbes is known as the immune system.
 The immune system consists of a complex network of cells and their interactions.
 It is specifically designed to eliminate infectious organisms from the body .
 This is possible since the organism is capable of distinguishing the self from non-
self ,and eliminate non- self.
THE IMMUNE SYSTEM :

7. THE IMMUNE SYSTEM ORGANS :
Immune Molecules :
I. Antibody
II. Complement (MHC)
III.Cytokines
IV. Adhesive molecules
Immune Cells:
i. Lymphocytes : T cells , B cells and NK cells
ii. Phagocytes : Dendritic cells ,macrophage ,PMN
Immune Gene :
Immune Tissues (or) Organs:
Immune gene are also involved in some defence mechanisms.
Ex: Meek1, Nrg, lic
i. Primary Lymphoid Organs
ii. Secondary Lymphoid Organs

8. i. Primary Lymphoid Organs - Where Immune Cells develop
I. Bone marrow
II. Thymus
Site for development and maturation of lymphocytes.
The cells of the immune system originate in and mature here.
ii. Secondary Lymphoid Organs - Where the Immune response Is Initiated
I. Spleen
II. Lymphatic vessels
III.Lymph nodes
IV. Adenoids and tonsils
 MALT (Mucosal Associated Lymphoid Tissue)
 GALT (Gut Associated Lymphoid Tissue)
 BALT (Bronchus Associated Lymphoid Tissue)
 SALT (Skin Associated Lymphoid Tissue)
 NALT (Nasal Associated Lymphoid Tissue)
Sites for lymphocytes and antigen interaction. It not for cell
development. (final differentiation, activation may be performed) The cells of the
adaptive immune system recognize here the pathogens

9. i. Bone Marrow :
The bone marrow is the site of generation of all circulating blood cells in the
adult, including immature lymphocytes

12. ii. Thymus :
 The structure of thymus :
Cortex
i. outer cortex : immature T cells ( thymus cells)
ii. inter cortex : thymus epithelial cell, macrophage , DC
Medulla
Mature T cells + thymus epithelial cell, macrophage , DC

13.  The function of thymus :
 The thymus is the site of T cell maturation
 Barrier function：blood-thymus barrier
 Secrete cytokine and thymulin-like molecules
i. Thymosin
ii. thymulin
iii. Thymopoietin
To promote the proliferation , differentiation of thymus cells

14.  The structure of spleen :
iii. Spleen :
*white pulp
Central arteriole
periarteriolar lymphoid sheaths (PALS)
T–cell area : around the central arteriole contain T cells ,
dendritic and macrophage
B -cell area: lymphoid follicles contain B cells and
macrophage and dendritic cells
i) primary lymphoid follicle
ii) secondary lymphoid follicle
*Red pulp:
cellular cords : B cells , plasma cells and macrophage ,DC
venous: blood

15.  The Structure of thymus :

16.  The function of spleen:
 The site of T and B cells residence
 B cells : thymus-independent area
 T cells : Thymus –dependent area
 Site of immune response to antigens
 Synthesize some bioactive substance
 component of complete
 Filtering blood

17. iii. Lymphoid Nodes :

18.  The Stururure of spleen:
 Cortex :
 Outer cortex:thymus-independent area : B cell-rich area
 lymphoid follicle/lymphoid nodule :
 primary lymphoid follicle : without germinal center mature and
naïve B cells
 secondary lymphoid follicle : with germinal center activated B
cells and memory B cells and macrophage
 Paracortex: T cell-rich area+ dendritic cells
 Medulla :
 medulla cords: macrophage and plasma cells
 medulla sinus

19.  The function of lymphoid node:
 The site of T and B cells residence
 B cells : thymus-independent area
 T cells : Thymus –dependent area
 Site of immune response to antigens
 Part of Recirculation of lymphocytes
 Filtering blood

21. TYPES OF IMMUNITY:

22. INNATE IMMUNITY (Inborn or Inherited Immunity):
 Innate immunity is a natural immunity which may be typically passed on from
one generation to other generation.
 It is a first line of immune response.
 Non-adaptive Immunity
 Relies on mechanisms that exist before infection
 It found in all multicellular organisms
 It is also known as birth immunity.
 Innate immunity is divided into two types, there are
 i) Specific Innate Immunity
 ii) Non-Specific Innate Immunity
Specific Innate Immunity Non-Specific Innate Immunity
It is an type of Innate Immunity It is also a type of Innate Immunity
It act as against specific organisms It not act as against specific organisms
Its shows different between self and foreign cells Not able to identify
Ex : Chicken Box (Not comes again) Ex : Pathogenic Diseases, etc..

23. ACQUIRED IMMUNITY (Adaptive Immunity):
 Acquired immunity is a active immune organ, make goals to target the specific
bacteria (or) unwanted microbes.
 It is a Second line of response (if innate fails)
 It is adaptive immunity
 Relies on mechanisms that adapt after infection
 It found in vertebrate organisms
 Handled by T- and B- lymphocytes
 One cell determines one antigenic determinant
 It is also known as Adaptive immunity.
 Innate immunity is divided into two types, there are
 i) Active Acquired Immunity
 ii) Passive Acquired Immunity

24. i) Active Acquired Immunity
 Immunity produced by the body for develops in response to an infection (or)
Vaccination.
 It’s classified into 2 types,
Natural Active Acquired Immunity
* Antibodies developed in response
to an Infection
Ex: Measles, Small Box
Aritifical Active Acquired Immunity
* Antibodies developed in response
to an vaccination
Ex: BCG, DT, TT
ii) Passive Acquired Immunity
 Immunity produced by the body for develops after received antibiotics from
someone (or) somewhere else.
 It’s a readymade immunity.
 It’s classified into 2 types,
Natural Passive Acquired Immunity Artificial Passive Acquired Immunity
• Antibodies received from mother
through breast milk, placenta
Ex: Mother’s Milk
* Antibodies received from a medicine
Ex: From a gamma globulin injection
or infusion.

25. BARRIERS :
i) Physical Barrier :
 Skin – Act as physical barrier to destruct of microbes which enter via skin.
 Sweet – which kill different pathogen
 Tears – Have lysozymes protective chemicals that lyses cells.
 Saliva – Also has lysozymes
 Mucus – Can trap pathogen which are the sneeze, coughed, washed away (or)
destroyed by chemicals (Nose hairs)
ii) Chemical Barrier :
 PH – Stomach acid (HCL) destroys pathogen , vaginal part, Urinary tract.
 Interferon – Macrophages activation (Phagocytosis – cell eating process)
 Lysozymes – In saliva & tears

26. iii) Phagocytic Barrier :
(Neutrophils, Macrophages and NK cells)
 Ingest and destroys microbes by endocytosis and phagocytosis)
iv) Inflammatory Barrier :
 Tissue damage and infection induce leakage of vascular fluid, containing serum
protein with antibacterial activity
Determination of Immunity:
I. Species and strains
II. Age
III.Hormonal Influences
IV. Nutrition

28. TYPES OF IMMUNITY:

29. Mechanism of active immunity :
 Body’s immune system provide protection by synthesizing antibodies or
immunoglobulins in response to an antigen.
 Primary immune response takes place when the host is attacked by certain
microbes for first time. The antibodies start to generate after certain period as
the binding of an antigen with its particular antibody is very specific.
 Secondary immune response occurs when an individual is being attacked by the
same antigen subsequently. It is a rapid process.
 Acquired active immune response takes two distinct forms- humoral and cell
mediated response.

30.  Immunity that is mediated by antibodies
 Can be transferred by to a non-immune recipient by serum
 Mediated by B cells
 Rapid reacts will occurs in onset.
 Does not reacts on tumour & transplantation
Humoral immunity :
Cell Mediated immunity (or) Cellular immunity :
 Immune response in which antigen specific T cells dominate
 Mediated by T cells
 Slowly reacts occurs in onset
 Do reacts on tumour & transplantation