Immune System

1
Immune System

• Is a self / non-self recognition and
  achieved by having every cell display a marker
  based on the major histocompatibility complex.

2
RBCs
3
 
4
Source of immune cells (Lymphoid organs)

• Primary organs bone marrow and the thymus gland
  .
• Secondary organs Adenoids, tonsils, spleen ,
  lymph nodes , Peyer's patches and the appendix.

Surface barriers or mucosal immunity
1. Skin. 2. Mechanically, pathogens
are expelled from the lungs by coughing ,
sneezing and ciliary movement of respiratory
cells. 3. Sticky mucus in respiratory and
gastrointestinal tracts. 4. Saliva, tears and
nasal secretions contain lysoenzyme antinfective
agents. 5. Vaginal secretions are also slightly
acidic . Spermine and zinc in semen destroy
pathogens. Lactoperoxidase is a powerful
antinfective enzyme found in mother's milk. 6.
Highly acidity of stomach.
5
Kinds of phagocytes according to their origin

• Promonocytes made in bone marrow and released
  into the blood and called circulating monocytes.
• Macrophages of liver called Kupffer cells.
• Macrophages of brain called microglia.
• Macrophages of kidney called mesoangial cells.

Types Of Phagocytes

• Natural killer cells (large granular lymphocytes
  ) move in the blood and lymph and attach to the
  glycoproteins on the surfaces of infected virus
  and bacteria and kill them.
• 2. Polymorphonuclear neutrophils, phagocytes
  that have no mitochondria and get their energy
  from stored glycogen.
• 3. Eosinophils are attracted to cells coated with
  complement

6
(No Transcript)
7
Types of Immunity

• Innate immunity The innate immunity system is
  what we are born with and it is nonspecific all
  antigens are attacked pretty much equally. Each
  immu ne cells conjugate with the antigen by
  pattern-rcognition receptors.
• Acquired immunity Occurred as a response to the
  infection and is of two types
• A. Humoral immunity.
• B. Cell mediated
  immunity.

8
Cell mediated ImmunityT- cells originated from
bone marrow lymphocyte which migrate to thymus
gland to multiply and carry genetic information
and tested for recognition and binding to
antigen. Processing of T-cells occurs largely
during foetal life and early childhood .There
are three types of T-cells A. Helper T-Cells
Secrete lymphokines that stimulate cytotoxic T
cells and B cells to grow and divide , attract
neutrophils and enhance the ability of
macrophages to engulf and destroy microbes. B.
Killer T-cells Known as cytotoxic T-cells
Secrete lymphotoxins which cause cell lysis.C.
Memory T-cells Are programmed to recognize and
respond to a pathogen once it has invaded.D.
suppressor T cell Suppresses the immune
response of B cells and other T cells once the
end of destroy the invaders.
9
2. Humoral ImmunityThe humoral immune response
involves a complex series of events after
antigens enter the body. First, macrophages take
up some of the antigen and attach it to class II
MHC molecules, then bind the antigen to T helper
cells which become stimulated and divide and
secrete stimulatory molecules called
interleukins. The interleukins activate any B
lymphocytes to bind to the antigen. The activated
B cells then divide and secrete antibodies.
Finally, the secreted antibodies bind the
antigen and help to destroy it.AntibodiesAntib
odies are Y-shaped proteins called
immunoglobulins (Ig) and are made only by B
cellsCategorize antibodies into five main
classes IgM, IgG, IgA, IgD, and IgE .
10
The antibodies inactivate antigens by (a)
Complement fixation. (b) Neutralization. (c)
Agglutination. (d) Precipitation.
11
(No Transcript)
12
Stem cells

• Some call them magic seeds, for their
  ability to replicate indefinitely and
  morphologically into any kind of tissue. Stem
  cells have traditionally been characterised as
  either embryonic (pluripotent) or tissue-specific
  (multipotent). Stem cells are the source of all
  cells - brain, skin, heart and others - that make
  up the human body. Just like a plant stem that
  branches into leaves and flowers, stem cells
  branch out to form different bits of our bodies.

13
Source of stem cells

• Pre-implantation embryos.
• Embryo from IVF.
• The fluid that surrounds a developing baby in the
  womb pre-implantation embryos.
• Embryo from IVF.
• Fluid that surrounds a developing baby in the
  womb.
• Umbilical cord.
• Bone marrow cells (Haematopoietic stromal stem
  cells).

14

• Advantage of adult stem cells
• Adult stem cells offer the opportunity to
  utilize small samples of adult tissues, to obtain
  an initial culture of a patient's own cells for
  expansion and subsequent implantation in the same
  person (Autologous transplant). This process
  avoids immune rejection by the recipient and also
  protects the patients from viral, bacterial or
  other contamination from another individual
  (donor) as in case of allogenic transplant.
• Disadvantages
• Culturing adult stem cells in-vitro is very
  difficult and has not been possible for some
  types.
• They have a very short life, when cultured
  in-vitro as compared to embryonic cells.

15

• Stem cells Heart disease
• Congestive heart failure results from loss
  or dysfunction of heart muscle cells. The disease
  afflicts 4.8 million people , with 400,000 new
  cases each year. The disease result from coronary
  heart disease , heart attack , the sudden close
  of the blood vessels supplying oxygen to the
  heart.
• Two major cells of the heart
• Cardiomyocyte that contracts to eject the blood
  out of the heart's main pumping chamber (
  ventricle).
• Vascular endothelial cells which form the inner
  lining of the blood vessel.
• Smooth muscle cells which form the wall of the
  blood vessel.
• The heart has a large demand for blood
  flow, and these specialized cells are important
  for developing a new network of arteries to bring
  nutrients and oxygen to the cardiomyocytes after
  a heart has been damaged.

16

• Stem cell therapy of heart failure
• Injection of selected bone marrow cells
  with a high capacity to develop into cells of
  multiple types ( haematopoietic stem cells). When
  these cells injected into the damaged wall of the
  ventricle, these cells led to the formation of
  the of new cardiomyocytes , vascular endothelium,
  and smooth muscle cells. Thus generating de novo
  myocardium , including coronary arteries,
  arterioles, and capillaries. The newly formed
  myocardium occupied 68 percent of the damaged
  portion of the ventricle nine days after the bone
  marrow cells were transplanted. The partial
  repair of the damaged heart muscle suggest that
  the transplanted haematopoietic stem cells
  respond to signals in the environment near the
  injured myocardium.
• Vasculogenesis Is the in situ differentiation of
  mesodermal precursors to angioblasts that
  differentiate into endothelial cells to form the
  primitive capillary network. Vasculogenesis is
  limited to early embryogenesis and is believed
  not to occur in the adult.
• Angiogenesis the sprouting of new capillaries
  from the preexisting blood vessels and occurs in
  both the developing embryos and postnatal life.

17
Neuronal stem cells

• Every sensation, action and thought
  explains the complicated processes of the central
  nervous system (CNS), which consists of the brain
  and the spinal cord. The brain is the central
  computer of our body interpreting outside
  information and controlling every action. The
  spinal cord connects the brain with the rest of
  the body by sending out millions of electrical
  signals. Neuronal cells are responsible for
  receiving and processing every piece of
  information the brain sends the rest of the body.
  Neurons are made up of four partsthe cell body
  which houses the nucleus and most of the cell
  organelles, dendrites, an axon, and axon
  terminals. Dendrites are bush like projections
  that bring information from other neurons to the
  cell body. The axon, a longer projection, sends
  information away form the cell body.
• Injuries of spinal cord is irreversible
  and cause paralysis and the information from
  brain and other regions of the body are blocked.
  This disease affects many millions of people
  around the world .

18

• Defects of spinal cord injury led to
• Swelling causes additional damage to the spinal
  cord as pressure builds in the confined space
  between the cord and vertebrae as a result of
  scar tissue that builds up around the area of
  injury which blocks the neurons from reconnecting
  once the cord has been severed.
• Swelling cuts off the blood supply to the neurons
  and glial cells which intern lead to additional
  neuronal cell death and migration of more immune
  cells to the injury site.

19

• Stem cell therapy
• Reconnection must be reestablished and
  activate new neurons and glial cells to
  regenerate and replace the injured ones. Once
  nerve cells were damaged they were gone,
  eliminating hope for complete recovery from
  paralysis.
• Scientists recently discovered that new
  neurons in specific regions of the adult
  mammalian brain . Neural stem cells were isolated
  from the dentate gyrus of the hippocampus and the
  walls of the ventricular system called the
  ependymal layer. The progeny of these stem cells
  differentiate in the granule cell layer, meaning
  neurogenesis continues late into adult rodent
  life. These stem cells also migrate along the
  rostral migratory stream to the olfactory bulb,
  where they differentiate into neurons and glial
  cells .

20

• Derived undifferentiated embryonic stem cells (ES
  cells) from fetal spinal cord tissue and then
  mature them into cells that are suitable to
  implant into the damaged spinal cord. When using
  ES cells, researchers have two options they can
  treat ES cells, allowing them to mature into CNS
  cells in vitro before transplantation, or they
  can directly implant differentiated cells and
  depend on signals from the brain mature the
  cells.
• Treating injured spinal cord of rats with
  undifferentiated embryonic stem cells (ES cells)
  from fetal spinal cord tissue led to marked
  differentiation of it , filling the area normally
  occupying by glial scarring. After five weeks the
  stem cells had migrated further away from the
  implantation site. Although a number of them had
  died, there was still enough for the rats to have
  a growing supply of neurons and glial cells. Most
  of the surviving cells were oligodendrocytes and
  astrocytes, but some neurons were found in the
  middle of the cord. The rats regained limited use
  of their legs. Paralysis had been cured!!

21
Stem cells
22
(No Transcript)
23
(No Transcript)
24
(No Transcript)
25
Sources of Stem cells
26
(No Transcript)
27
(No Transcript)
28
Good Luck