Physio 2

1. Immunity Overview

2. Types Of Immunity
1. Innate Immunity
2. Acquired Immunity
A. Naturally Acquired Active Immunity
B. Artificially Acquired Active Immunity
C. Naturally Acquired Passive Immunity
D. Artificially Acquired Passive Immunity

3. Overview of Immunity

4. Naturally Acquired Active Immunity
 Naturally acquired active immunity is obtained
when a person is exposed to antigens in the
course of daily life, direct exposure.
 The immune system then responds by producing
antibodies and specialized lymphocytes. Usually,
the immunity is for a long term.
 Examples, include measles, pox.

5. Artificially Acquired Active Immunity
 Artificially acquired active immunity results from
vaccination or immunizations.
 Vaccination introduces specially prepared antigens
into the body.
 These antigens are no longer able to cause
disease, but they are still able to stimulate an
immune response.

6. Naturally Acquired Passive Immunity
 Naturally acquired passive immunity involves
the
natural transfer of antibodies from a mother to a
child.
 An expectant mother is able to pass some
of her antibodies to her fetus across the
placenta.
 In addition, certain antibodies are also passed
from the mother to the child during breast
feeding.
 Generally immunity lasts only as long as the
antibodies are active usually a few weeks or 6

7. Artificially Acquired Passive Immunity
 Artificially acquired passive immunity involves
an
injection of antibodies into the body.
 These antibodies come from an animal or
human who is already immune to the disease.

8. Immunity Overview
 Immunity: The body's ability to fight off
harmful micro-organisms –
PATHOGENS- that invade it.
 The immune system produces
antibodies or cells that can deactivate
pathogens.
 Fungi, protozoans, bacteria, and
viruses are all potential pathogens.
 Antigen: Molecules from a
pathogen or foreign organism that
provoke a specific immune
response.

9. The Immune System - includes all parts of
the body that help in the recognition and
destruction of foreign materials. White
blood cells, phagocytes and lymphocytes,
bone marrow, lymph nodes, tonsils,
thymus, and spleen are all part of the
immune system.

10. Function of the immune
system
 Destroy pathogens
 Detect and kill abnormal cells
 Remove dead cells and other debris
from the body

11. The Immune System is the Third Line of
Defense Against Infection

12.  Third-Line Defenses - Sometimes the second line
of defense is still not enough and the pathogen is
then heading for the body's last line of defense, the
immune system.
 The immune system recognizes, attacks, destroys,
and remembers each pathogen that enters the
body. It does this by making specialized cells
and antibodies that render the pathogens harmless.
 Unlike the first line and second line defense the
immune system differentiates among pathogens.
 For each type of pathogen, the immune system
produces cells that are specific for that particular
pathogen.

13.  An antibody is a protein produced in
response to an antigen.
 Antigens are macromolecules that elicit an
immune response in the body. The most
common antigens are proteins and
polysaccharides.

14.  Antigens can enter the body from the environment.
These include
inhaled macromolecules (e.g., proteins on cat hairs
that can trigger an attack of asthma in susceptible
people)
ingested macromolecules (e.g., shellfish proteins that
trigger an allergic response in susceptible people)
molecules that are introduced beneath the skin (e.g.,
on a splinter or in an injected vaccine)

15. antigens can be generated within the cells
of the body. These include
proteins encoded by the genes of viruses
that have infected a cell
Proteins that are encoded by mutant
genes; such as mutated genes in cancer
cells

16.  protect against specifically identified threats
(i.e. may defend against one particular bacterial
infection but not a different one)
 many specific defenses develop after birth upon
exposure to an antigen; an antigen can be a
pathogen (disease-causing organism), foreign
protein (e.g. toxin), abnormal or infected body
cell, foreign tissue transplant
 specific defenses produce a state of long-term
protection known as “Immunity”
Specific defenses

17. Immunity
Immunity = specific resistance to disease
 depends on coordinated activity of T & B
lymphocytes
Humoral immunity involves the antibodies and the B
cells that they secret them; is directed against
extracellular pathogens
 Cellular immunity involves T lymphocyte that
directly attack other cells; defense against abnormal
cells & intracellular pathogens

18. Humoral and cellular
immunity
Humoral Immunity Cellular Immunity
Type of cells B-Cells T-Cell
Antibody Involvement Yes No
Location of pathogen Extracellular Intracellular

19.  Immunity is the result of the action of two types lymphocytes,
the B lymphocytes and the T lymphocytes.
 B cells produce antibodies that are secreted into the blood
and lymph.
 T cells attack the cells that have antigens that they
recognize.

20. Shared feature of B & T
lymphocyte
 Specificity of receptors: Both B & T
lymphocyte have specific receptor for
specific antigen
 Diversity of receptors: There are huge
numbers of different lymphocyte each
with its own unique antigen receptor
 Regulation of activation: Activation of B &
T cells leads to process clonal expansion
 Memory: Respond to subsequent
exposure to the same antigen

21. Antigen: Self Antigen
 There are a vast number of antigen
outside the body. There are also
internal antigen called self antigen.
 Lymphocyte must recognize antigen
from pathogen while ignoring self
antigen

22. Antigen receptor- Specificity
 The surface of mature B & T lymphocyte
studded with lymphocyte antigen
receptor that allows these cells to identify
their particular antigen shape
 The antigenic specificity of B & T
lymphocyte is determined by the shape
of their antigen receptor
 B & T cells have a related structure and
similar function, there are differences in
their shape and the way they interact
with antigen

23. Antigen receptor
 The B cell antigen receptor is Y-shape
antibody molecule and directed
against antigen in the extracellular
fluid
 When the antigen occupy the antigen
binding site on the B cell receptors,
the receptor signals the cell that
antigen found

24. Antigen receptor
 T lymphocyte receptor is not:
1. Membrane bound antibody
2. Y-Shaped
 T cell directed against the body’s
own cells when they are invaded

25. Antigen receptor
 When antigen bind receptors and
activate the receptors, the cell divides
and make clone with identical receptor
 This matching mechanism called
clonal selection

26. Humoral (Antibody-Mediated) Immunity
◦ Involves production of antibodies against foreign
antigens.
◦ Antibodies are produced by a subset of lymphocytes
called B cells.
◦ B cells that are stimulated will actively secrete antibodies
and are called plasma cells.
◦ Antibodies are found in extracellular fluids (blood
plasma, lymph, mucus, etc.) and the surface of B cells.
◦ Defense against bacteria, bacterial toxins, and viruses
that circulate freely in body fluids, before they enter
cells.
◦ Also cause certain reactions against transplanted tissue.