BSC 2011 Chapter Notes - Chapter 43: Antigen-Presenting Cell, Antimicrobial Peptides, Innate Immune System
30 Nov 2016
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Document Summary
For a pathogen a bacterium, fungus, virus, or other disease-causing agent the internal environment of an animal is a nearly ideal habitat. The animal body offers a ready source of nutrients, a protected setting, and a means of transport to new environments. From the perspective of a cold or flu virus, we are wonderful hosts. From our vantage point, the situation is not so ideal. Fortu- nately, adaptations have arisen over the course of evolution that protect animals against many pathogens. Dedicated immune cells in the body fluids and tissues of most animals specifi- cally interact with and destroy pathogens. For example, figure 43. 1 shows an immune cell called a macrophage (brown) engulfing rod-shaped bacteria (green). Some immune cells are types of white blood cells called lymphocytes (such as the one shown at left with bacteria). Most lymphocytes recognize and respond to spe- cific types of pathogens.
