為什么在農(nóng)場長大對你的免疫系統(tǒng)有好處

為什么在農(nóng)場長大對你的免疫系統(tǒng)有好處

Health experts have known for years that kids who grow up on a farm have fewer incidences of allergies and asthma than city kids, but continued research is helping them better understand the connection between the immune system and microbes only found in that setting.

健康專家多年來就知道，在農(nóng)場長大的孩子比在城市長大的孩子過敏和哮喘的發(fā)生率更低，但持續(xù)的研究正在幫助他們更好地理解免疫系統(tǒng)和微生物之間的聯(lián)系，而這種聯(lián)系只有在農(nóng)村才能找到。

Researchers may have figured out what it is about life on a farm that protects kids from allergies and boosts their immune systems. (Photo: Andy Dean Photography/Shutterstock)

The Amish children all had a large proportion of neutrophils, white blood cells that are part of the so-called innate immune system. The Amish kids' neutrophils "were newly emerged from their bone marrow, evidence of a continual low-grade reaction to microbial invaders," the Times reported. In contrast, the Hutterite kids had "old" neutrophils, and researchers found their blood was full of another type of immune cell, eosinophils, which provoke allergic reactions.

阿米什兒童都有很大比例的中性粒細(xì)胞，即白細(xì)胞，是所謂的先天免疫系統(tǒng)的一部分。據(jù)《泰晤士報(bào)》報(bào)道，阿米什兒童的中性粒細(xì)胞“是從他們的骨髓中新出現(xiàn)的，這證明他們對微生物入侵者的反應(yīng)持續(xù)低下”。相比之下，赫特人的孩子有“老”中性粒細(xì)胞，研究人員發(fā)現(xiàn)他們的血液中充滿了另一種類型的免疫細(xì)胞，嗜酸性粒細(xì)胞，會引發(fā)過敏反應(yīng)。

They made this connection with the help of young pigs. They essentially did a fecal transplant, placing the Amish babies' poop into the intestines of newborn pigs, essentially testing the hygiene hypothesis with the help of pigs, which have an immune system more similar to humans. The results were an increased development of immune cells, particularly lymphoid and myeloid cells in the intestines.

他們在小豬的幫助下建立了這種聯(lián)系。他們進(jìn)行了糞便移植，將阿米什嬰兒的糞便植入新生豬的腸道，在豬的幫助下測試衛(wèi)生假說，豬的免疫系統(tǒng)與人類更相似。結(jié)果是增強(qiáng)了免疫細(xì)胞的發(fā)育，尤其是腸道內(nèi)的淋巴細(xì)胞和髓細(xì)胞。

The research was published in Frontiers in Immunology.

這項(xiàng)研究發(fā)表在《免疫學(xué)前沿》雜志上。

The Amish babies involved in the experiment all lived in rural homes with farm animals. (Photo: Elizaveta Galitckaia/Shutterstock)

According to the Centers for Disease Control and Prevention, 6.8 million children in the U.S. have been diagnosed with asthma and about 17 percent of kids suffer from respiratory allergies to things like pollen and mold. But over the last few decades, health care providers have observed that kids who grow up on farms are much less likely to be affected by these conditions than their urban-dwelling peers.

根據(jù)美國疾病控制和預(yù)防中心的數(shù)據(jù)，美國有680萬兒童被診斷出患有哮喘，約17%的兒童對花粉和霉菌等呼吸道過敏。但在過去幾十年里，衛(wèi)生保健提供者發(fā)現(xiàn)，在農(nóng)場長大的孩子比在城市生活的同齡人更不容易受到這些條件的影響。

What's more, researchers found that when the mice were exposed to farm dust, they produced a protein in their lungs called A20. When they deactivated this protein, these mice had a normal allergic response to the dust mites.

更重要的是，研究人員發(fā)現(xiàn)，當(dāng)老鼠暴露在農(nóng)場的灰塵中時(shí)，它們的肺部會產(chǎn)生一種叫做A20的蛋白質(zhì)。當(dāng)他們停用這種蛋白質(zhì)時(shí)，這些老鼠對塵螨有正常的過敏反應(yīng)。

Researchers confirmed these findings with human surveys where they found that people who suffer from allergies and asthma have a deficiency in A20 protein. Finally, they took a look at the kids growing up on farms who develop asthma and allergies. You guessed it — those kids have a mutation in their A20 gene that impedes the production of A20 protein.

研究人員通過人類調(diào)查證實(shí)了這些發(fā)現(xiàn)，他們發(fā)現(xiàn)患有過敏和哮喘的人缺乏A20蛋白。最后，他們對在農(nóng)場長大的孩子進(jìn)行了調(diào)查，這些孩子患有哮喘和過敏癥。你猜對了——這些孩子的A20基因發(fā)生了突變，阻礙了A20蛋白的產(chǎn)生。

Researchers were especially interested in dust on dairy farms. (Photo: Ewa Studio/Shutterstock)

By narrowing down the mechanisms behind certain asthmatic and allergic reactions, these researchers may have opened the door for the development of vaccines and treatment options for people who suffer from these conditions.

通過縮小某些哮喘和過敏反應(yīng)背后的機(jī)制，這些研究人員可能為開發(fā)針對這些疾病患者的疫苗和治療方案打開了大門。