second line of defense

• Defensive cells are phagocytic cells (neutrophils and macrophages), eosinophils, natural killer cells
• Eosinophils: attack pathogens that are too large for phagocytosis, such as parasitic worms
• Macrophages: consume pathogens and clean up debris
• Natural killer cells are a type of white blood cell that can kill infected or cancerous cells
• Interferons are small proteins that slow viral reproduction
• Interferons attract macrophages and natural killer cells that destroy infected cells; stimulate neighboring cells to make proteins that prevent the viruses from replicating
• The complement system assists other defensive mechanisms; is the group of proteins that enhances both non-specific and specific defense mechanisms; destroys pathogens, enhances phagocytosis, stimulates inflammation
• Inflammation destroys invaders and helps repair and restore damaged tissue
• There are 4 signs of inflammation: redness, heat, swelling, pain
• Fever is an abnormally high body temperature caused by pyrogens (lipopolysaccharides)
• A mild or moderate fever helps fight bacterial infection
• A very high temperature over 105F or 40.6C is DANGEROUS