5.3.4 Nonreactivity to self antigens

A unique and remarkable property of immune system is to respond and eliminate any foreign antigen (Non self), while not producing any harmful effect against the own antigen (self). It is sometimes called as tolerance towards the self antigen. Any deviation from the above in which immune system starts reacting towards the self antigen leads to a condition what we call as autoimmune diseases .

5.3.5 Specialization

Both humoral and cellular immune system responds to the foreign pathogens in a different way. The responses are different against extracellular and intracellular pathogens. Each type of response is unique for a particular type of pathogen and is specialized to perform specific functions.

5.3.6 Clonal expansion

It is another unique property of immune system in which the lymphocyte starts producing similar kind of cells upon exposure to an antigen in order to eliminate the pathogen more effectively and more rapidly. The cells formed after clonal expansion has similar surface markers and responds to similar kind of antigen.

5.3.7 Homeostasis

Every process in the body has a regulatory mechanism. The immune responses are produced against an antigen or pathogen upon entry inside the body and wane following the clearance of antigen. This is done in order to maintain homeostasis mechanism inside the body. Any deviation from the homeostasis leads to an immunological disease condition.