What is immunology ......?
Definition :-
Immunology is the branch of science which deals with the study of immune system, immune responses to foreign substance and their role in resisting infection by pathogen .
( study of the component and function of the immune system )
What is immunity .....?
The immunity is the state of protection from infectious disease .
- The tern immunity is derived from Latin word , immunis. Immunity in the fact freedom or exempt.
- The concept immunity is believed to be started by Edward Jenner in England .
History of immunology :-
- Immunology is claimed to have emerged out of some observation in the ancient past . In 430 BC when Thucydides, who had recovered from the plague would not contract the disease a second time, and could nurse the plague patient.
- The technique of variolation was significantly improved by Edward Jenner an English physician , in 1798.
( The term variolation refers solely to inoculation with smallpox virus and is not interchangeable with vaccination ).
- The latter term was first used in 1800 soon after Edward Jenner introduced smallpox vaccine derived from cowpox, an animal disease distinct from smallpox.
- Recognition of Immunology as a Science:-
- Immunology got recognition as a science in 1880 when the world witnessed a spate ofprogress brought about by the work of Louis Pasteur, who was studying with cholera bacterium, Pasteur had succeeded in culturing this bacterium, and had shown that chickens developed.
- Pasteur speculated that aging had weakened the virulence of cholera bacterium, and that such attenuated pathogens could be used for inoculation. Pasteur used the term “vaccine” forthe attenuated strain in recognition of the work of Jenner with cowpox; the term “vaccine” is derived from the Latin world ‘vacca , meaning “cow”.
- In 1885, Pasteur administered a series of attenuated rabies virus preparations to a boy, Joseph Meister, who was repeatedly beaten by a mad dog. The boy survived and later became the custodian of Pasteur Institute. The latter was established in 1888 and became the professional centre for work in immunology.
Cell-Mediated and Humoral Immunity Co-exist:-
- During 1940s, Merill Chase successfully transferred immunity against tuberculosis organism by transferring white blood cells between guinea pigs. This demonstration lighted again the interests in cellular- immunity.
- The identification of lymphocytes as the cells responsible for both cell-mediated andhumoral immunity during 1950s by using tissue culture techniques.
- The existence of two types of lymphocytes (B lymphocytes and T lymphocytes) demonstrated by Bruce Glick were the major breakthrough in solving the controversy. B. Glick advocated that B lymphocytes are involved in humoral immunity, whereas T lymphocytes play role in cell-mediated immunity.
Immunity also Reacts to Non-pathogenic Substances:-
- Jules Bordet demonstrated around 1900 that the immunity also reacts to non pathogenic substances such as red blood cells from other species. Serum taken from an animal.
- Karl Landsteiner and others demonstrated that inoculating an animal with almost anyorganic chemical induces production of antibodies that would react specifically to the chemical.
Concept of Selective Theory:-
- In 1900, Paul Ehrlich proposed the concept of selective theory. He demonstrated thatcells in the blood expressed a variety of receptors on their surface, which he called “side-chain receptors”.
Clonal Selection Theory:-
- Clonal selection theory has been widely accepted and in recognition Burnet was awardedNobel prize in 1960, which he shared with Sir Peter Medawar.
- Twenty four years later in 1984, Niels Jerne was also awarded the Nobel prize for his contributions, which led to the discovery of clonal expansion concept and evaluation of the idiotype network in the regulation of immune responses.
Structure of Antibody:-
- In their pioneer work, Rodney R. Porter and Gerald M. Edelman demonstratedthrough enzyme cleavage experiments that the four polypeptide chains of antibody(immunoglobulin) molecule can be cleaved into three pieces, i.e., two antibody fragments (Fab) and one crystallisable fragment (Fc).
Fig :- (a), (b) structure of antibodies
- Porter and Edelman were awarded the Nobel prize in 1972.
- Subsequently, Wu and Kabat demonstrated in 1970 that there occur hypervariable regions in the antibody molecule.
Major Histocompatibility Complex (MHC):-
- Peter Gorer in the mid 1930s developed the concept that the rejection of foreign tissue takes place due to an immune response to cell-surface molecules; the molecules now called histocompatibility antigens.
- During these studies, Gorer identified four groups of genes,designated I through IV, that encoded blood-cell antigensantigens.
- Gorer and Snell carried out the work in 1940s and 1950s and demonstrated that antigens encoded by the genes in the group designated II participated in the rejection of transplanted tumors and other tissue. Snell called these genes as histocompatibility genes.
Technique of Somatic Hybridization:-
- A major breakthrough was witnessed in 1975, when George Kohler and Ceaser Milstein demonstrated a technique of somatic hybridization and used it to produce immunologically homogenous monoclonal antibodies. Monoclonal antibody producing technique popularized by the name hybridoma technology.
List of Nobel prize winners in immunology :-
1901 E.A. Von Behring (Germany) for the work on serum therapy especially its application against diphtheria.
1905 R. Koch (Germany) for the investigations concerning tuberculosis.
1908 E. Metchnikoff (Russia) and P. Ehrlich (Germany) for their work on immunity (respectively, phagocytosis/cellular theory and humoral theory).
1913 C.R. Richet (France) for the work on anaphylaxis.
1919 J. Bordet (Belgium) for the discoveries relating to immunity (complement).
1930 K. Landsteiner (Austria/USA) for the discovery of human blood groups.
1951 M. Theiler (South Africa) for the discoveries and developments concerning yellow fever.
1957 D. Bovet (Italy/Switzerland) for the discoveries related to histamine and compounds, which inhibit action of histamine and other substances on the vascular system and the skeleton muscles.
1960 Sir F.McFarlane Burnet (Australia) and Sir P.B. Medawar (Great Britain) for the discovery of acquired immunological tolerance.
1972 G.M. Edelman (USA) and R.R. Porter (Great Britain) for their discovery concerning the chemical structure of antibodies.
1977 R. Yalow (USA) for the development of radioimmunoassays of peptide hormones.
1980 B. Benacerraf (USA), J. Dausset (France) and G.D. Snell (USA) for their discoveries concerning genetically determined structures on the cell surface (major histocompatibility complex) that regulate immunological reactions.
1982 S. K. Bergstrom (Sweden), B. I. Samuelsson (Sweden) and J. R. Vane (UK) for their discoveries concerning prostaglandins and related biologically active substances.
1984 N.K. Jerne (Denmark/Switzerland) for theories concerning the specificity in development (lymphocyte clonality) and control of the immune system
1984 G.J.F. Köhler (Germany/Switzerland) and C. Milstein (Argentina/Great Britain) for the discovery of the principle for production of monoclonal antibodies.
1987 S. Tonegawa (Japan/USA) for the discovery of the genetic principle for generation of antibody diversity.
1990 J.E. Murray and E.D. Thomas (USA) for their discovery concerning organ and cell transplantation in the treatment of human diseases.
1996 P. Doherty and R. Zinkernagel (USA) for their discovery of how the immune system recognizes virus-infected cells uncovered the general mechanisms of the immune system to distinguish foreign agents from its own cells and tissues.
2011 B.A. Beutler (USA) and J.A. Hoffmann (France) for their discoveries concerning the activation of innate immunity and R. M. Steinman (USA) for his discovery of the dendritic cell and its role in adaptive immunity.
( For scope and application check this blog )..........
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