Immune Systems

IMMUNE SYSTEMS

INTRODUCTION

Immunity may be defined as - ‘the state of being immune to or protected from a disease especially an infectious disease’.

Importantly, this particular state is invariably induced by having been exposed to the antigenic marker on an microorganism that critically invades the body or by having been duly immunized with a vaccine capable of stimulating the production of specific antibodies.

Immunology, the generation of an immune response solely depends upon the prevailing interaction of three cardinal components of the immune mechanism, such as :

·        immunogen stimulation,

·        humoral immune system, and

·        cellular immune system.

Since 1901 and as to date the epoch making discovery and spectacular evolution of ‘immunobiotechnology’ i.e., conglomeration of immune system variants, across the world has revolutionized not only the safer quality of life of human beings but also provided a broad spectrum of newer avenues in combating the complicated dreadful not-so-easy diseases of the present day.

Immune Response : In reality, the immune responses do refer to such processes whereby animals (including humans) give rise to certain specifically reactive proteins (known as ‘antibodies’) and adequate cells in response to a great number of foreign organic molecule and macromolecule variants. Based on the scientifically demonstrated proofs and evidences the generalized immune response essentially possesses four major primary characteristic features, such as :

(a) discrimination,

(b) specificity,

(c) anamnesis, and

(d) transferability by living cells.

1. Discrimination

It usually designates the ‘ability of the immune system’ to have a clear-cut discrimination between ‘self’ and ‘nonself’ ; and, therefore, it invariably responds exclusively to such materials that happen to be foreign to the host.

2. Specificity

It refers to such a response that is extremely specific either solely for the inducing material or antigen to which the immune cells or antibodies would interact in a much prominent and greater strength.

3. Anamnesis

It most commonly refers to the critical ability to elicit a larger specific response much more rapidly on being induced by a ‘second exposure’ to the same very foreign antigen. It is also termed as the anamnestic response or the immunologic memory, as illustrated in Fig. 9.1.

4. Transferability by Living Cells

Interestingly, the active immunity is observed to be exclusively transferable from one particular inbred animal specimen to another by the respective ‘immune cells’ or ‘lymphocytes’, and definitely not by immune serum*.

Adjuvants : It has been duly observed that there exist quite a few nonspecific substances, namely : alum, mineral oil, that essentially do possess the abiliy to prolong as well as intensify the ensuing immune response to a particular antigen on being injected simultaneously with the antigen. In fact, such materials are termed as adjuvants by virtue of the fact that they profusely aid the immune response.

Immune Serum : It is capable of transferring temporarily the passive immunity, whereas the active immu-nity certainly needs the long-term regenerative ability of the living cells.

Innate Resistance : Besides, the aforesaid nonspecific defenses, one may usually encounter certain degree of innate resistance (i.e., inherent resistance) to some specific human diseases.

Examples : Various examples are as given below :

(i) Canine distemper,

(ii) Hog and Chicken cholera, and

(iii) Measles.

Nevertheless, the effect of measles is observed to be comparatively quite mild specifically for the individuals belonging to the European ancestry, whereas for the individuals belonging to the Pacific Island it proved to be quite severe.

Special Points : There are fwo special points, such as :

(a) The innate resistance of an individual to measles exclusively depends on such other cardinal factors as : age, general health, nutritional status, and genetic factors, and

(b) Natural selection from several generations being duly exposed to ‘measles virus' probably led to the more frequent inheritance of genes which eventually offered certain extent of resistance to the virus.