Powerful chemical substances secreted by lymphocytes. These molecules help direct and regulate the immune responses.
An organ of the immune system where lymphocytes develop and congregate. These organs include the bone marrow, thymus, lymph nodes, spleen, and various other clusters of lymphoid tissue. Blood vessels and lymphatic vessels are also lymphoid organs.
A small white blood cell produced in the lymphoid organs and essential to immune defenses. B cells, T cells, and NK T cells are lymphocytes.
A bodywide network of channels, similar to the blood vessels, which transports lymph to the immune organs and into the bloodstream.
A small beanshaped organ of the immune system, distributed widely throughout the body and linked by lymphatic vessels. Lymph nodes are garrisons of B and T cells, dendritic cells, macrophages, and other kinds of immune cells.
A transparent, slightly yellow fluid that carries lymphocytes, bathes the body tissues, and drains into the lymphatic vessels.
A major group of lymphokines and monokines.
A protein produced by cells that stimulates antivirus immune responses or alters the physical properties of immune cells.
An immune system function that is inborn and provides an all-purpose defense against invasion by microbes.
Redness, warmth, and swelling produced in response to infection; the result of increased blood flow and an influx of immune cells and their secretions.