What is the amazing mechanism of ‘nutritional immunity’ that attacks bacteria with ‘iron’? -GIGAZINE

The human body takes a protective measure called “nutritional immunity” to prevent the growth of bacteria when it is infected, and “iron” is an important element used for nutritional immunity. In addition, iron is an essential and harmful element for living organisms. Pharmaceutical scientist Derek Lowe explains such iron.

The War for Iron | Science | AAAS
https://www.science.org/content/blog-post/war-iron

Iron is an essential element for enzymes that are important for life activities, but it is relatively difficult to obtain biologically available iron in the soil or the ocean. Pure iron is exposed to oxygen in the air and is easily oxidized. An iron(III) compound isSolubilitylow and insolubleIron(III) oxideit changes to a substance commonly known as rust.

In addition, iron and oxygen are essential and harmful components for living organisms. Iron isactive oxygenand can be harmful to cells. However, as iron is a very important element biologically, micro-organismsSiderophoreWe devised a method to prevent the harmful effects of active oxygen using a protein called

Bacteria that invade the body also need iron to reproduce. Therefore, when humans are infected with bacteria, the absorption and transport of iron from the intestine is limited in order to limit their growth. During an infectious disease, the reduction in the amount of iron, zinc and manganese available to bacteria provides an effective defense against bacteria. This is what Lowe calls “nutritional immunity.”

A type of white blood cell in the body when it is infected with bacteriamacrophageiron-containing proteinsrecipienthaveextracellular vesicleIt captures iron by releasingBy capturing iron, the iron needed for bacterial growth is not available.ReportShe has been.

In previous experiments,salmonellaIn mice infected with , we identified a mechanism by which the endoplasmic reticulum of macrophages stimulates the production and release of extracellular vesicles in response to infection.

In addition, some bacteriared blood cellit was found to dissolve iron and deprive hemoglobin of iron. The fact that some bacteria have such a mechanism suggests that there is a protective layer that traps them before they can use iron, and that there must be other immunity secrets yet to be discovered, said Mr Low.