Macrophage

a special type of cell that forms part of the IMMUNE SYSTEM of vertebrates. Macrophages are derived from MONOCYTES in the blood system and can move to infected or inflamed areas of the body using PSEUDOPODIA. In these areas, they surround, engulf and degrade broken cells and other debris, including microbes, by means of the process called PHAGOCYTOSIS.

Taken from Dictionary of Science

Vaccine

a modified preparation of a VIRUS or BACTERIA that is no longer dangerous but can produce an immune response. It therefore gives immunity against infection with the actual disease. Vaccines can be administered by mouth or by a hypodermic syringe and are not effective immediately as it takes time for the recipient's IMMUNE SYSTEM to develop a memory for the modified virus or bacterium by producing specific ANTIBODIES.

Taken from Dictionary of Science