| − | Macrophage is a large cell that helps the body defend itself against [[disease]] by surrounding and destroying foreign organisms ([[viruses]] or [[bacteria]]). | + | Macrophage is a large cell that helps the body defend itself against [[disease]] by surrounding and destroying foreign organisms ([[viruses]] or [[bacteria]]).<ref>http://www.cdc.gov/vaccines/about/terms/glossary.htm#m</ref> |