Mehreen Ashraf
Saima
New life College
faculty: Ramesh Kumar
Subject: Life Sciences
date: 15jan’2016
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History and impact
The types and functions of cells in the immune
system.
How cells communicate and recognize antigen
Structure and functions
Active and Passive Immunity
Anything that causes an immune response is
called an antigen. An antigen may be harmless,
such as grass pollen, or harmful, such as the flu
virus. Disease-causing antigens are
called pathogens. The immune system is
designed to protect the body from pathogens.
In humans, the immune system begins to
develop in the embryo. The immune system
starts with hematopoietic (from Greek, "bloodmaking") stem cells. These stem cells
differentiate into the major players in the
immune system (granulocytes, monocytes, and
lymphocytes). These stems cells also
differentiate into cells in the blood that are not
involved in immune function, such as
erythrocytes (red blood cells) and
megakaryocytes (for blood clotting). Stem cells
continue to be produced and differentiate
throughout your lifetime.
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The word “Immuis” means free from burden
and “immunitas” means exemption from
government taxes and this provided the
English terminology Immunity.
Immunity is a broad definition: This is a
protective or defense mechanism of our body,
which leads us to a healthy life.
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Inborn or innate immunity: It is present at birth;
This is our First Line Of Defense.
Acquired or specific: It is not present at birth but
becomes part of our immune system as the
lymphoid system develops.
1970: WHO defined immunity as immune
response to antigen ( Foreign body) in form of
Humoral ( activation of B-lymhocytes)
Cellular (by activation of T-lymphocytes
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Macrophages
 B cells
 T cells
Factor
Mode Of Action
-Keratin layer of intact skin
-Acts as mechanical barrier
-Lysozyme in tears and other secretions -Degrades peptidoglycan in bacteria
cell wall
-Respiratory cilia
-Elevate mucus containing trapped
organisms
-Low pH in stomach and vagina;
-Retards growth of microbes
fatty acids in skin
-Surface phagocytes
-Ingest and destroy microbes
(eg. alveolar macrophages)
-Defensins (cationic peptides)
-Create pores in microbial membrane
-Normal flora of throat, colon
-Occupy receptors which prevent
and vagina
colonization by pathogens
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Kill virus infected cells
Ingest and destroy microbes
Ingest and destroy microbes, and present antigen to helper
T-cells
Inhibit viral replication
C3b is an opsonin, membrane attack complex creates holes
in bacterial membranes
Sequester iron required for bacterial growth
Elevated temperature retards bacterial growth
Limits spread of microbes
Causes hypermutation in retroviral DNA and mRNA
Neutrophils
Macrophages and dendritic cells
Inferons
Complement
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Active immunity is resistance acquired
after
contact with
foreign antigens, eg, microorganisims
This contact may consist of :
Clinical or subclinical infections
Immunization with live or killed infectious
agents or their antigens.
Exposure to microbial products (eg, toxins and
toxoids)
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Passive immunity is resistance based on
antibodies preformed in another host.
Other forms of passive immunity are IgG
passed from the mother to the fetus during
pregnancy.
IgA passed from the mother to the newborn
during breast feeding.
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Passive-active immunity involves giving both
preformed antibodies (immune globulins) to
provide immediate protection and
Vaccine to provide long term protection
These preparations should be given at different
sites in the body to prevent the antibodies from
neutralizing the immunogen in the vaccine.
This approach is used in the prevention of
Tetanus, Rabies and Hepatitis B
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https://en.wikibooks.org/wiki/Immunology/
Introduction
http://www.powershow.com/view/11d062ZDRmN/Introduction_to_Immunology_power
point_ppt_presentation
http://www.biology.arizona.edu/immunolog
y/tutorials/immunology/page2.html