Antibodies are Y-shaped proteins produced by B cells and plasma cells in response to the presence of an antigen. Their primary function is to recognize and bind to specific antigens, marking them for destruction by other components of the immune system.

Humoral immunity is the antibody-mediated immune response. It involves the production of antibodies by B cells and plasma cells in response to the presence of an antigen. Antibodies bind to antigens, marking them for destruction by other components of the immune system.

T cells are a type of white blood cell that plays a crucial role in the immune system. They are responsible for recognizing and destroying infected cells, as well as helping B cells differentiate into plasma cells, which produce antibodies.

Cytotoxic T cells, also known as killer T cells, are a type of T cell that is responsible for killing infected cells. They recognize and bind to infected cells, releasing toxic substances that destroy the cells.

Cytokines are small proteins that are produced by various immune cells in response to the presence of an antigen. They play a crucial role in regulating immune responses, including the activation, differentiation, and proliferation of immune cells.

Cell-mediated immunity is the T cell-mediated immune response. It involves the activation of T cells, which recognize and destroy infected cells, as well as helping B cells differentiate into plasma cells, which produce antibodies.

The complement system is a complex network of proteins that plays a crucial role in the immune system. It is activated by the presence of an antigen and helps in the destruction of infected cells, as well as the activation of other immune cells.

Innate immunity is the first line of defense of the immune system and does not require prior exposure to an antigen. It involves physical barriers, such as the skin and mucous membranes, as well as chemical barriers, such as antimicrobial peptides and proteins.

Memory cells are a type of immune cell that is generated after an immune response to an antigen. They remain in the body and are able to recognize and respond quickly to the same antigen if it is encountered again in the future.

Adaptive immunity is the second line of defense of the immune system and requires prior exposure to an antigen. It involves the activation of B cells and T cells, which recognize and respond to specific antigens.

MHC molecules, also known as major histocompatibility complex molecules, are proteins that are expressed on the surface of cells. They play a crucial role in the immune system by presenting antigens to immune cells, such as T cells, which can then recognize and respond to the antigens.

Humoral immunity is the antibody-mediated immune response. It involves the production of antibodies by B cells and plasma cells in response to the presence of an antigen. Antibodies bind to antigens, marking them for destruction by other components of the immune system.

Dendritic cells are a type of antigen-presenting cell that plays a crucial role in the immune system. They capture and process antigens, and then present them to T cells, which can then recognize and respond to the antigens.

Cell-mediated immunity is the T cell-mediated immune response. It involves the activation of T cells, which recognize and destroy infected cells, as well as helping B cells differentiate into plasma cells, which produce antibodies.

Natural killer cells are a type of cytotoxic lymphocyte that plays a crucial role in the immune system. They recognize and destroy infected cells and tumor cells, without the need for prior sensitization to the specific antigen.