innate immune system
TRANSCRIPT
INNATE IMMUNE SYSTEM
Presented By: Ayesha Aftab Zainab Nooruddin
Dept. of BioinformaticsMohammad Ali Jinnah University.
Innate Immune System
Second Line of Defense
First Line of Defense
PhysicalBarriersPhysicalBarriers
ChemicalBarriers
ChemicalBarriers
Skin
Mucous
CELLS PROTEINS
Macrophages
Neutrophills
Phagocytes
NK CellsDendritic
Cells
Monoocytes
Complement
Toll-Like
INNATE IMMUNITY
☻ Innate immune system refers to nonspecific defense mechanisms that come into play immediately or within hours of an antigen's appearance in the body
☻ Natural immunity
FIRST LINE of DEFENSE
☻ It stops the microbe from entering into our body
☻ The skin and mucous membranes☻ Normal Body Flora: They help to protect a
host from becoming infected with more harmful micro-organisms by acting as a physical barrier
SECOND LINE of DEFENSE
☻ If microbes do manage to get inside the body then the second line of defense is activated
☻ This includes the working of different type of cells and proteins
PHAGOCYTES
☻ From the Greek phagas, to eat, and kutos, a vessel (or cell)
☻ Recognition of a microbial invader
☻ Quickly followed by its engulfment
MONOCYTES
☻ Monocytes develop in the bone marrow and reach maturity in the blood.
☻ Large, smooth, lobed nuclei ☻ Abundant cytoplasm that contains granules. ☻ Ingest foreign or dangerous substances ☻ Present antigens to other cells☻ Monocytes leave the blood stream after 20–40 hours☻ Transform into macrophages or dendritic cells
MACROPHAGES
☻ Macrophages - large eaters are the sentries of the immune system
☻ Produced by stem cells in the bone marrow
☻ Distributed throughout the body just below the surface of the skin and mucous membranes
☻ In their normal, resting state, macrophages are the janitors of the body
☻ During this stage, macrophages proliferate slowly
DENDRITIC CELLS
☻ Specialized antigen-presenting cells
☻ Long outgrowths called dendrites☻ Engulf microbes ☻ Present in skin☻ The inner lining of the nose☻ The lungs☻ The stomach☻ The intestines☻ Migrate to the lymphoid tissues
where they interact with T and B cells to initiate the adaptive immune response
NEUTROPHILLS
☻ Neutrophils make up the majority of white blood cells in the body
☻ Their sole job is to respond to the site of an infection in order to attack and eat invaders
☻ Are present in the bloodstream☻ Neutrophils respond to the
location of infection and inflammation after detecting chemical signals in the blood
☻ Short lived☻ Dead neutrophils make up a
large proportion of puss
NATURAL KILLER CELLS
☻ Natural killer cells are called “natural” killers because they are ready to kill as soon as they are formed
☻ Natural killer cells recognize and attach to infected cells or cancer cells, then release enzymes and other substances that damage the outer membranes of these cells
☻ Natural killer cells are important in the initial defense against viral infections
☻ Also, natural killer cells produce cytokines that regulate some of the functions of T cells, B cells, and macrophages
COMPLEMENTS PROTEINS
☻ The complement system consists of more than 30 proteins that act in a sequence: One protein activates another and so on. This sequence is called the complement cascade.
☻ Complement proteins have many functions in acquired immunity as well as innate:
☻ Killing bacteria directly☻ Helping destroy bacteria by attaching to them and thus making the
bacteria easier for neutrophils and macrophages to identify and ingest☻ Attracting macrophages and neutrophils to a trouble spot☻ Neutralizing viruses☻ Helping immune cells remember specific invaders☻ Promoting antibody formation☻ Enhancing the effectiveness of antibodies☻ Helping the body eliminate dead cells and immune complexes (which
consist of an antibody attached to an antigen)
TOLL-LIKE RECEPTORS
☻ Toll-like receptors (TLRs) are a class of proteins
☻ They are usually expressed in cells such as macrophages and dendritic cells
☻ Once these microbes have breached physical barriers they are recognized by TLRs, which activate immune cell responses
REFERENCES
☻ http://www.microbiologyonline.org.uk/about-microbiology/microbes-and-the-human-body/immune-system
☻ http://www.novimmune.com/science/innate.html☻ http://www.merckmanuals.com/home/immune-disorders/biology-
of-the-immune-system/innate-immunity☻ http://www.biology.arizona.edu/immunology/tutorials/
immunology/page3.html☻ http://www.ncbi.nlm.nih.gov/books/NBK26846/☻ http://www.immunologyexplained.co.uk/HowItWorks.aspx