Inflammation occurs in both non-specific and specific defense responses. They circulate in the blood stream. Release of histamine Histamine dilates blood vessels and causes seepage of fluid into tissues. Vasodilation causes warmth and redness. Seepage of fluid causes swelling.
Phagocytes follow the chemical trail to damaged tissue and engulf invaders and cellular debris.
Agents involved in clotting wall off the infection to keep it from spreading. Tissues are repaired after inspection stopped. This system mounts the most efficient attack. The system has 2 branches - both of which are active during most invasions. The main actors are B and T lymphocytes.