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Microbiology · Chapter 10

Evading the Body's Defenses

Your immune system has two great weapons: phagocytes that eat invaders and antibodies that tag them for destruction. Successful pathogens survive by dodging these defenses. Explore three classic escape tricks — then flip between the normal immune attack and the microbe's counter-move.

Pick an escape trick

Tap a trick on the right, then flip the toggle above.
Three ways to hidetap a trick to begin
Three escapes, one idea: a capsule hides you from phagocytes, antigenic variation hides you from antibodies, and going intracellular hides you inside the very cell antibodies can't follow you into.
Watch for overwhelming or reactivated infection. Encapsulated microbes (pneumococcus, meningococcus, Hib) can overwhelm asplenic and sickle-cell patients — vaccinate them. Intracellular hiders like M. tuberculosis stay latent for years and reactivate under steroids, TNF-inhibitors, or HIV.