What type of immunity is provided by antibodies in the plasma?

The type of immunity provided by antibodies in the plasma is known as humoral immunity. This branch of the immune system is primarily mediated by B cells, which are a type of white blood cell. When B cells encounter an antigen, they can differentiate into plasma cells that produce antibodies specific to that antigen. These antibodies circulate in the blood plasma and bind to the antigens, which can neutralize pathogens, mark them for destruction, or prevent their ability to infect cells.

Humoral immunity is distinct from other types, such as cell-mediated immunity, which involves T cells and does not rely on antibodies. It also differs from passive immunity, which refers to the temporary immunity obtained through the transfer of antibodies from one individual to another (such as from mother to child). Innate immunity describes the body's first line of defense mechanisms that one is born with, which do not involve the specific recognition of pathogens.

Thus, the role of antibodies within humoral immunity is critical for targeting specific foreign substances (antigens) and is a key component of the adaptive immune response.