2. Immunology
• Latin word meaning exempt
• Protection from diseases
• To rid the body from foreign particle eg microbes and abnormal cells
• Our immune system response involves the interplay between our nonspecific and specific
immune responses
3. Defense system
• In the process of evolution, the body of organisms has developed the
property of distinguishing
• “self” and “nonself”,
• the “self” is accepted and “nonself” is rejected or degraded.
• For the rejection or degradation of “nonself”, organisms’ body has
evolved a remarkably versatile defence system called immune system
that operates via various mechanisms, which are collectively grouped
under the name immunity or resistance (defence).
4. General overview of immune system
• Innate immunity
Fast acting
Less specific recognition
Early during evolution
e.g barrier to the infection such as skin and mucus
• Adaptive immunity
Specificity
Memory and recall
5. Conti..
• Cells of immune system
Leucocytes originating from bone marrow cells
• Disruption of immune system
Allergy
Autoimmunity
immunodeficiency
6. History
• Immunology is claimed to have emerged out of some
observations in the ancient past. The ancient people observed
that individuals who had recovered from certain infectious
disease were not attacked by the same disease again, i.e., they
became immune to the disease.
• Another important observation dates back to 430 BC when
Thucydides, the great historian of the Peloponnesian War, wrote
that only those individuals who had recovered from the plague
would not contract the disease a second time, and could nurse
the plague patients. Thucydides’s observation is perhaps the
earliest written reference to the phenomenon of immunity.
7. Development of Vaccination:
• The first recorded attempts to induce immunity deliberately
were made by Chinese and Turks in the 15th century. They
either inhaled the dried crusts derived from small pox pustules
or inserted them into small cuts in the skin (this technique is
called variolation).
• Lady M.W. Montagu, the wife of the British ambassador to
Constantinople, observed in 1718 that there were positive effects
of the technique of variolation applied on to the native
population. She also applied this technique on her own children
and found the positive results.
8. • The technique of variolation was significantly improved by Edward
Jenner, an English physician, in 1798. He was intrigued by the fact
that milkmaids, who had contracted the mild disease cowpox,
became immune to the dreaded smallpox. Jenner reported to the
Royal Society in London the value of immunization with cowpox as a
means of protecting against smallpox; a clear case of vaccination.
• Thus, he did on the basis of the fact that when he inoculated a 8-year
old boy, James Phipps, with cowpox content, the boy escaped from
smallpox infection. Jenner’s explanation regarding cowpox
vaccination against smallpox established the scientific credibility of
vaccination to prevent disease and was accepted by the scientists and
physicians of the time.
9.
10.
11. Discovery of Phagocytosis and Cell-
Mediated Immunity:
• In 1883, a Russian scientist Elie Metchnikoff while studding
infection of the common water-flea (Daphnia) by a fungus
demonstrated that certain white blood cells, which he termed
phagocytes, were able to ingest (phagocytose) microbial
pathogens and other foreign substances. This was the first
demonstration of the process of phagocytosis.
• Moreover, noting that these phagocytic cells were more active in
immunized animal and contribute to its immune state,
Metchnikoff hypothesized that cells were the major effector of
immunity and gave the concept of cell-mediated immunity.
12. Discovery of Humoral Immunity:
• Von Behring and Kitasato demonstrated in 1890 that serum (the
liquid, non-cellular component of coagulated blood) from animals
previously immunized to diphtheria could make unimmunized
animals immune to the disease when it was administered to the
latter.
• Since it was a discovery which showed that the immunity was
mediated by non-cellular body fluids (known at the time as humors),
the door of humoral immunity was opened.
• For this discovery, Behring was awarded Nobel prize in 1901.
Humoral immunity, however, was fully confirmed only during 1930s
mainly through the efforts of Elvin Kabat and other workers who
demonstrated that a fraction of scrum called gamma-globulin (now
called immunoglobulin or antibodies) was found responsible for
immunity acquired following immunization.
13.
14. Scope of Immunology
• Our knowledge of the immunological processes underlying the
reactions of the body to infectious agents, to tumours, and to
transplanted tissues and organs has advanced remarkably by
using modern techniques, including those developed by
biochemists and molecular biologists.
• These techniques have enabled the identification of genes
coding for molecules like the T-cell receptor and MHC
molecules. The genes coding for immunologically important
molecules have been cloned and relatively large amounts of pure
recombinant proteins have been produced.
15. • It is now possible to culture many different cell types in vitro
and to clone these cells so that a population with an identical
genetic makeup is obtained.
• Many different strains of inbred mice, including ‘knock-out’ and
‘knock-in’ mice, have been developed for the investigations of
cellular interactions, gene inactivation’s, etc. The role of a
number of gene products has been elucidated by producing
transgenic animals and studying the effect of the introduced
genes.
16. • Immunologists have developed many new techniques, including
novel ways of producing a homogeneous immunoglobulin
preparation, viz., monoclonal antibody, by using impure
antigens. The development of these strictly defined reagents
revolutionalized immunoassays and detection systems that
employ antibodies.
• Their potential in the treatment of infectious diseases, cancer
patients, organ transplants, etc. is being actively investigated
and a number of clinical trials have been performed. In addition
to antibodies, other immunologically important molecules have
been produced and are being developed as therapeutic agents.
17. • The introduction of flow cytometry has revolutionized the
analysis of cell populations and the use of polymerase chain
reaction has increased the sensitivity of the detection of
microorganisms.
• The interplay between cells and molecules of the immune
system is extremely complex. We are only now beginning to
understand the intricacies of immune recognition. Some
molecules appear to have many different functions depending
on their location or the presence of other molecules.
18. • The possibility of harnessing these powerful reagents to aid the
elimination of not only pathogenic microorganisms, but also
cancer cells is being actively pursued.
• The ability to predict the minimum structures that can induce
protective immunity will allow the development of more
effective and safer vaccines. It may also become possible to
develop novel ways of treating autoimmune diseases, allergic
conditions and tumours, and to develop new strategies to
reduce transplant rejection.
19. • Thus it can be seen that immunity in its original meaning,
referring to resistance to infections by means of a specific
immune response, is only one activity of a complex system in
animals.
• The total activity of the cellular system is concerned with
mechanisms for preserving the integrity of the individual with
far-reaching implications in embryology, genetics, cell biology,
tumor biology and many non-infectious disease processes.
