Who are what produces the antibody?

Plasma cells are the antibody-producing cells.

Plasma cells are a type of white blood cell that are found in the bone marrow and other lymphoid tissues. They are derived from B cells, which are activated when they encounter a foreign antigen. Once activated, B cells differentiate into plasma cells, which then begin to produce antibodies.

Antibodies are proteins that bind to specific antigens and help to neutralize them. They are essential for the body's immune response to infection.

Plasma cells can produce large amounts of antibodies, and they can continue to do so for a long period of time. This is important for providing the body with a sustained immune response to infection.

Plasma cells are also important for providing immunity against future infections. When a person is exposed to an antigen for the first time, the body's immune system will produce antibodies against it. These antibodies will remain in the body and provide immunity against future infections with the same antigen.