In this article we will discuss about the attributes of acquired immunity.
Acquired immunity or Adaptive immune response reflects the presence of a functional immune system that is capable of specifically recognizing and selectively eliminating foreign microorganisms and molecules. Unlike innate immune responses, adaptive immune responses are not the same in all the members of a species, but are specific to antigenic challenges.
1. Antigenic specificity:
The antigenic specificity of the immune system permits it to distinguish subtle differences among antigens. Antibodies can differentiate between two molecules that differ by only a single amino acid.
2. Diversity:
The immune system is capable of generating tremendous diversity in its recognition molecules, allowing it to specifically recognize billions of uniquely different structures on foreign antigens.
3. Immunologic memory:
Cells and molecules of the innate immune system treat each encounter with a particular microbial invader as if they were meeting it for the first time. On the other hand, the adaptive system has the capacity to use the initial encounter with a particular stimulus (e.g. a specific microbe) to modify or adapt its response (s) to any subsequent encounters with that same stimulus.
This immunologic memory allows the adaptive immuno-system to tailor its responses to cells or molecules that it encounters on multiple occasions.
Once the immune system has recognized and responded to an antigen, it exhibits immunologic memory; that is, a second encounter with the same antigen induces a heightened state of immune reactivity. Because of this attribute, the immune system can confer life-long immunity to many infectious agents (Fig. 6.3).
4. Self/Non-self-recognition:
The immune system normally responds only to foreign antigens indicating that it is capable of Self/Non-self recognition. The ability of the immune system to distinguish self from non-self and respond only to non-self-molecules is essential, for the outcome of an inappropriate response to self-molecules which can be a fatal autoimmune disease.
