This document provides an overview of the immune system and immunology. It discusses the immune response, functions of the immune system, types of immune cells, acquired immunity, humoral responses, B-cell activation and proliferation. The key points are: immunology studies the immune system and its response to protect the body from pathogens; the immune system recognizes foreign substances and acts to neutralize or destroy them; acquired immunity creates immunological memory to enhance response to subsequent exposures. B-cells play a major role in the humoral immune response by differentiating into plasma cells that secrete antibodies specific to antigens.

1. Presented By
U.Aishwarya
ROLL NO-21M1310
2nd Msc Biotechnology

2. INTRODUCTION
IMMUNE RESPONSE
FUNCTIONS OF IMMUNE SYSTEM
TYPES AND CELLS OF IMMUNE SYSTEM
ACQUIRED IMMUNITY
HUMORAL RESPONSES
B-CELL ACTIVATION
PROLIFERATION

3. Immunology is the study of structure and function of the
immune system.
It is concerned with the immune response .
It makes a defence mechanism of the host against a
particular disease or infection.

4. Collective and co-ordinated response to the introduction
of foreign substances in an individual mediated by the
cells and molecules of the immune system.
It recognizes foreign substances or microbes and acts to
neutralize or destroy them.
It is composed of widely distributed cells ,tissues and
organs.

5. To protect humans from pathogenic micro-organism.
Pathogenic micro-organism (pathogens) which means the
micro-organism capable of causing infection.
Recognise and clear damage self components.

8. It s also called as Specific and adaptive immunity.
It is second line of response (if innate fails).
Relies on mechanism that adapt after infection.
“Eliminates or destroy the pathogenic micro-organism”.
This was handled by T and B cells .
One cell determine one antigenic determinants.
It is not presented at the birth but becomes part of our
immune system as a lymphoid system develops .

9. Acquired immunity creates immunological memory after
initial response.
It leads to an enhanced response yo subsequent
encounters with that pathogen.
.
The phagocytic cells crucial to non-specific immune
responces are intimately involved in activating the specific
immune responses.

11. Lymphocytes are one of many types of
produced in the bone marrowby the proces of
haematopoesis.
Lymphocytes leave the bone marrow ,circulate in the
blood and the lymphatic system.
The immune system is a complex network of cells known
as immune cells that include lymphocytes.

12. The immune response involving the
transformation of B cells into plasma
cells that produce and secrete antibodies
to a specific antigen.
Can recognise protein,polysaccharide
and nucleic acid antigens.
Provides immunity to extracellular
bacteria ,virus and toxins.

13. • The humoral response differ considerably depending on
whether the humoral reponse results from activations of
native lymphocytes(primary response) or memory
lymphocytes(secondary response).
• In both cases activation leads to production of secreted
antibodies of various isotypes ,which differ in their ability
to mediate specific effector functions.

14. • Primary immune response refers to any immune response
of the immune system that includes the production of
antibodies .
• Occurs in response to the primary contact of the antigen.
• Native B cells and T cells respond to the antigen.
• Lag phase is long(4-7 days)
• Takes a longer time to establish the immune response .
• Appears mainly in the lymph nodes and spleen.

15. • Secondary immune response refers to any immune
response of the immune system that occur in response to
the subsequent exposure to a particular antigen.
• Occurs in response to the second and subsequent
exposure to the same antigen.'
• Memory B cells respond to the antigens .
• Lag phase is short (1-4 days )
• Takes a short time to establish the immune response.
• Appears mainly in the bone marrow and then in the
spleen and the lymp nodes.

17. • Derives name from the
organ it matures (bursa of
fabricus in birds).
• In human it matures in
bone marrow.
• The lymphocyte which
arrives and develop in the
bone marrow is called B
lymphocyte.

18. • It is specific only to one
specific antigen.
• It produces antibodies
specific to the antigen to
which it was primed ,and
• It generates memory for
any similar antigenic
attack in future.

19. • When a native B cells first
encounters the antigen
that matches its
membrane bound antibody
• the binding of the antigen
to the antibody causes the
cell to devide rapidly .
• Its progeny differentiate
into

20. • Memory B Cells circulate
throughout the body in a
quiescent state untill
specific antigen is re-
encountered.

21. Plasma cells produce the antibody in a form that can be
secreted and have little or no membrane bound antibody.
Although plasma cells live only a few days .
They secrete enormous amounts of antibody during this
time.
It has been estimated that a single plasma cell can
secrete more than 2000 molecules of antibody per
second.

22. • Occurs in the peripheral lymphoid organ.
• Generation of plasma cells and memory B cells .
• In absence of antigen-induced activation ,native B cells
die within few weeks by apoptosis.
• The generation of mature B cells first occurs in the
embryo and continues throughout life.
• At the earliest developement stage pro-B Cells require
direct contact with stromal cells in the bone marrow.

23. Mature within the bone marrow.
The basic B cell function is to bind to an antigen receive
help from a coginate helper T cell and differentiate into a
plasma cell that secrete large amounts of antibodies.
B cell receptor allow the B cell to bind to a specific
antigen,against which it will initiate an antibody response.
The B Cell activation occurs in the secondary lymphoid
organ such as spleen and lymph nodes.

24. • After B cell mature in the bone marrow they
migrate to the blood.
• B cells actvatiob begins when the B cell
binds to an antigen.
• B cell activation is enhanced through the
activity of CD21,a surface receptor in
complex with surface protein CD19 and
CD81.
• Memory B cells activation begins with the
detection and binding of their antigen .

25. THANK YOU