The immune system protects the body from invading disease-causing organisms, or pathogens.
Innate defenses act immediately or within hours of a pathogen's appearance in the body.
Cilia in mucous membranes, which sweep out airborne pathogens and dust. Tears, nasal secretions and saliva, which contain bacteria-destroying enzymes. Granulocytes and macrophages are phagocytic white blood cells. This migration of white blood cells causes the redness and inflammation associated with infection. If an invading pathogen escapes the innate defenses, the body can launch an adaptive, or specific response against one type of antigen.