What are the leukocyte for recognizes foreign antigens?

T lymphocytes

T lymphocytes, also known as T cells, are a type of white blood cell that plays a central role in the body's immune response. They are responsible for recognizing and responding to foreign antigens, such as those found on bacteria, viruses, and other pathogens. T cells also play a role in immune surveillance, which is the process of constantly monitoring the body for any signs of infection or disease.

There are two main types of T cells: cytotoxic T cells (Tc cells) and helper T cells (Th cells). Cytotoxic T cells are responsible for killing cells that are infected with viruses or other pathogens. Helper T cells play a supporting role in the immune response by helping to activate other immune cells, such as B cells and macrophages.

T cells are activated when they come into contact with an antigen that is presented on the surface of an antigen-presenting cell (APC). APCs are cells that have the ability to capture and present antigens to T cells. When a T cell recognizes an antigen, it becomes activated and begins to proliferate, producing a large number of daughter cells that are specific for that antigen. These daughter cells then circulate through the body and help to eliminate the infection.

T lymphocytes play a critical role in the body's immune response and are essential for maintaining health and preventing disease.