B- lymphocytes produce 5 types of antibodies in response to any infection. some other types of cells are also produced like memory Cells , natural killer cells ,helper T cells . As the production of antibodies requires energy in form of ATP . Hence it is known as active immunity. In Passive immunity preformed antibodies are injected into the body.

Active immunity is the type of immunity that is acquired after an infection. It is a specific immune response that is induced when the body is exposed to a pathogen, such as a virus or bacteria. This type of immunity is long-lasting and provides protection against future infections by the same pathogen.

There are two main components of active immunity: humoral immunity and cell-mediated immunity. Humoral immunity involves the production of antibodies by B-cells, while cell-mediated immunity involves the activation of T-cells to directly kill infected cells.

During an infection, the immune system recognizes the pathogen as foreign and mounts an immune response. This response involves the activation of immune cells, such as B-cells and T-cells, which work together to eliminate the pathogen from the body. B-cells produce antibodies that specifically bind to the pathogen, marking it for destruction by other immune cells. T-cells, on the other hand, directly kill infected cells.

The immune response to an infection can take several days to develop. Initially, the immune system may not have specific antibodies or immune cells that can recognize and eliminate the pathogen. However, as the immune response progresses, B-cells and T-cells undergo clonal expansion, resulting in the production of a large number of specific antibodies and immune cells that can target the pathogen.

Once the infection is cleared, some of these immune cells remain in the body as memory cells. These memory cells can quickly recognize and respond to the pathogen if it enters the body again, leading to a rapid and robust immune response. This is the basis for active immunity, as the immune system has "learned" how to recognize and eliminate the pathogen.

Active immunity can also be acquired through vaccination, where a weakened or inactivated form of the pathogen or its components are introduced into the body. This stimulates the immune system to mount a response and produce memory cells, providing protection against future infections by the pathogen.

In summary, active immunity is acquired after an infection or vaccination and involves the production of specific antibodies and immune cells that can recognize and eliminate the pathogen. It provides long-lasting protection against future infections by the same pathogen.