Jellyfish Age Backwards: Nature's Secrets to Longevity by Nicklas Brendborg

Author:Nicklas Brendborg [Brendborg, Nicklas]
Language: eng
Format: epub
Tags: Science, Life Sciences, biology, Social Science, Gerontology, nature, Animals, Marine Life, Psychology, Developmental, Adulthood & Aging, Natural History, Marine Biology, Developmental Biology
ISBN: 9781529387926
Google: wYswEAAAQBAJ
Publisher: Hodder & Stoughton
Published: 2022-05-26T21:13:36+00:00

Chapter 15

Hiding in Plain Sight

When the United States began vaccinating against the measles virus in the 1960s, children fortunately stopped getting measles. But that wasn’t the only thing; suddenly, American children had plummeting risks of dying from all sorts of other infectious diseases, too. The same thing happened in European countries joining the effort. But how can a vaccine protect against infections that it’s not even targeting?

Like all other microbes that infect us, the measles virus is not a big fan of our immune system. Cells of the immune system are constantly on the lookout for invaders and will spring into action if an uninvited guest is discovered. Viruses like the measles virus fight back by hiding, by trying to trick the immune system and sometimes also by counterattack. This war between our immune system and various microbes is ongoing throughout our lives. It’s happening inside you at this very moment.

Pathogens have evolved various weapons to target the immune system, but the measles virus has found a particularly effective one. It can cause something you can think of as immune memory loss. Usually, certain cells of the immune system retain a memory of previous adversaries. This is clever, because it decreases the time it takes for the immune system to react if it encounters the same enemy again. Then, there will already be a tried-and-tested battleplan ready for deployment to rob the infection of the chance to take hold. This immune ‘memory’ is the reason vaccines can protect against developing a disease, and also the reason you only get diseases such as chickenpox once in a lifetime.

When the measles virus causes ‘memory loss’ in our immune system, though, all this valuable information is lost. This ­benefits the measles virus itself, but it’s also a boon for all sorts of other bacteria and viruses. Suddenly, these pathogens have a much easier time infecting us. Therefore, infection with the measles virus predisposes you to all sorts of other infections, too. In fact, it is estimated that the measles virus used to contribute to half of childhood deaths from other infections.

Such one-two punches are quite common in the world of infections. A straight right from an initial infection and then a left hook from a second one that exploits the chaos to its own benefit. On the one hand, this principle illustrates why vaccines were (and still are) the uncrowned king of medical science. But it is also bad news, because there are still plenty of dangerous microbes that we don’t have vaccines against yet.

A particularly good example is HIV, the virus that causes AIDS. HIV attacks certain cells of the immune system called T-cells. You can think of T-cells as the generals of the immune system, because they are responsible for orchestrating your immune responses. When HIV attacks T-cells, they eventually succumb to the virus. This means the immune system becomes weaker and weaker, and eventually it cannot keep up with all sorts of other microbes. As a result, HIV-infected people become vulnerable to otherwise harmless infections.

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