Immune System

IMMUNE SYSTEM

Being specific defence system it differentiates between self and nonself of the body.
Immunity is the power of resistance against any disease or foreign bodies based upon antigen antibody reaction.

Brief History

The idea first came to Edward Jenner (1797). He observed that milk-maids do not catch small pox.
By introducing the fluid from blister of milkmaid into the body of a boy could save him from small pox. This was termed as vaccination (vacca = cow).
Louis Pasteur (1869) working on the cholera bacteria of chicken discovered immunity.
Emil von Boehring (1890) discovered the passive immunity. He injected the serum from diphtheria patient into sheep’s body to develop antibodies which could cure the patient.
Milstein and Kohler (1975) developed the technique for preparing monoclonal antibodies through hybridoma cells and recombinant-DNA technology.

Related terms :

Antigen is the foreign substance which evokes the formation of antibodies in the body. It is always a large molecule, generally, protein or polysaccharide.
Antibody is the substance formed by the body against antigen hence is always specific to antigen.
Hapten : the substance of low molecular weight which itself can not evoke the antibody formation but can do so when jointed with other molecule, i.e. carrier.
Adjuvant : The substance which may or may not be antigenic itself but enhances the rate of antibody formation thus improving the immune response.
Freunds complete adjuvant (FCA) is such a mixture of killed mycobacteria, an oil and an emulsifier.
Epitope (or antigenic determinant) : The particular part or segment of the molecule or pathogen’s body that actually acts as antigen against which antibodies are formed.
Interferon. The antiviral protein secreted by macrophage obstructs the replication process of virus and prepares the host cells not be affected by virus.