Study reveals how cells differentiate between disease-causing and harmless invaders

A study conducted by UC San Diego biologists has revealed that roundworm intestinal cells, which have a similar structure to those found in humans, internalize bacterial toxins that inactivate certain processes. This activates an immune response, which results in the body creating an immediate attack against the disease-causing microbes. Animal cells detect an attack by poisons or disease-causing bacteria by monitoring the function of their own cells. If the cells detect a deficit in functions, they mount a number of antibacterial and antitoxin responses against invaders. The researchers found that a particular genetic system, called the ZIP-2 surveillance pathway, was used by the roundworm in detecting an infection by the disease-causing bacterium Pseudomonas aeruginosa. Also, a toxin in the bacterium, Exotoxin A, blocks protein synthesis in the intestine, which leads to increased protein levels of the ZIP-2 transcription factor to induce expression of defense genes.