Acquired immunity, also known as adaptive immunity, is a type of immunity that develops over time in response to exposure to pathogens such as viruses, bacteria, and other microorganisms. Unlike innate immunity, which is present at birth, acquired immunity is acquired during an individual’s lifetime through exposure to antigens, which are foreign substances that trigger an immune response.
Acquired immunity is characterized by the ability of the immune system to recognize and respond to specific antigens, which it does by producing specific antibodies or by activating specific immune cells. This specificity allows the immune system to selectively target and destroy invading pathogens while sparing healthy tissues.
There are two types of acquired immunity: humoral immunity and cell-mediated immunity. Humoral immunity involves the production of antibodies by B cells, which bind to and neutralize antigens. Cell-mediated immunity, on the other hand, involves the activation of T cells, which directly attack and destroy infected cells.
Acquired immunity can develop naturally as a result of exposure to pathogens or can be acquired through immunization, which involves the administration of a vaccine that contains a weakened or inactivated form of a pathogen. Immunization can also provide long-lasting protection against a specific pathogen, which can help prevent the spread of infectious diseases.
However, acquired immunity can also be harmful in certain circumstances, such as in autoimmune disorders, in which the immune system attacks the body’s own tissues, or in transplant rejection, in which the immune system recognizes transplanted organs as foreign and attacks them.
Overall, acquired immunity is a complex process that involves the coordinated efforts of various immune cells and molecules. Understanding the mechanisms of acquired immunity is essential for the development of effective vaccines and immunotherapies for infectious diseases and other disorders.
