免疫细胞发现可以改善抗击乙型肝炎的能力

StephenW

Immune cell discovery could improve the fight against hepatitis B

Westmead Institute for Medical Research
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IMAGE: PhD student Ratna Wijaya, Professor Golo Ahlenstiel and Dr Scott Read. view more

Credit: The Westmead Institute for Medical Research (WIMR)

For the first time, researchers at The Westmead Institute for Medical Research (WIMR) have identified and described a new and unique subset of human cells that are involved in the immune response against hepatitis B (HBV) infection. The discovery could help develop new treatments for HBV and inform future vaccine design.

Currently, HBV vaccination protects against subsequent infection through immunological memory - the vaccine 'trains' the immune system to eliminate pathogens when the body is exposed to the virus.

For years, immunological memory was thought to be driven by B and T immune cell responses. Recent studies in mice have suggested that natural killer (NK) cells can also 'remember' viral infections, but it remained unknown whether this applied to human viral infections.

Researchers from WIMR studied NK cells in humans who had been vaccinated against, or infected with HBV, and compared them to those who had not been exposed to the virus.

The study, undertaken by PhD student Ratna Wijaya and led by Professor Golo Ahlenstiel and Dr Scott Read, describes for the first time, the presence of memory NK cells (mNKs) in humans following exposure to HBV.

Professor Ahlenstiel said, "This finding is quite significant, as it helps our understanding of how the body fights against HBV following vaccination.

"Previously, we thought that the NK immune response was part of our 'innate' immune system. The innate immune system fights against all antigens (foreign bodies, such as viruses), rather than specifically targeting certain antigens. We have now confirmed that NK cells in humans can acquire an immunological 'memory', and specifically target HBV-infected cells in subsequent infections."

HBV is a virus that attacks the liver. Although some individuals who are infected with HBV can eliminate the virus from their body, others, particularly those who are infected in childhood, may develop chronic infections.

"Vaccines have been vital in preventing the spread of HBV," Professor Ahlenstiel said.

"However, not everyone who is vaccinated will experience the same level of protection. A percentage of those vaccinated - roughly five per cent - will not develop immunity against HBV. This means they can still develop an infection, including a chronic infection.

"Without proper treatment, chronic HBV can lead to serious complications, including liver cancer, and liver cirrhosis with chronic liver failure. It is vital that we prevent such infections where we can.

"We hope that, through our discovery, we can harness the anti-viral properties of mNKs to develop new treatments and improve vaccines so that everyone is protected against this virus."

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The research was published in Gut: https://gut.bmj.com/content/early/2020/03/29/gutjnl-2019-319252

StephenW

免疫细胞发现可以改善抗击乙型肝炎的能力

韦斯特米德医学研究所
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图像：博士生Ratna Wijaya，Golo Ahlenstiel教授和Scott Read博士。查看更多

图片提供：Westmead医学研究所（WIMR）

威斯米德医学研究所（WIMR）的研究人员首次确定并描述了一种新的独特的人类细胞亚群，参与了针对乙型肝炎（HBV）感染的免疫反应。这一发现可能有助于开发针对HBV的新疗法，并为将来的疫苗设计提供依据。

目前，HBV疫苗接种可通过免疫记忆来防止随后的感染-疫苗“训练”免疫系统以消除人体暴露于病毒时的病原体。

多年来，人们一直认为免疫记忆是由B和T免疫细胞反应驱动的。小鼠的最新研究表明，自然杀伤（NK）细胞也可以“记住”病毒感染，但是否将其应用于人类病毒感染仍是未知的。

WIMR的研究人员研究了已接种HBV疫苗或感染了HBV的人类NK细胞，并将其与未接触该病毒的人类NK细胞进行了比较。

这项由博士生拉特纳·维贾亚（Ratna Wijaya）进行，由Golo Ahlenstiel教授和斯科特·雷德（Scott Read）博士领导的研究首次描述了人类在接触HBV后存在记忆NK细胞（mNK）。

Ahlenstiel教授说：“这一发现非常重要，因为它有助于我们了解接种疫苗后人体如何抵抗HBV。

“以前，我们认为NK免疫反应是我们'先天'免疫系统的一部分。先天免疫系统与所有抗原（异物，例如病毒）抗争，而不是专门针对某些抗原。我们现在已经确认NK人类细胞能够获得免疫学上的“记忆”，并在随后的感染中特异性靶向被HBV感染的细胞。”

乙肝病毒是一种攻击肝脏的病毒。尽管某些感染了HBV的人可以从体内清除病毒，但其他人，尤其是那些在儿童时期感染过的人，可能会发展成慢性感染。

艾伦斯蒂尔教授说：“疫苗对于预防乙肝病毒的传播至关重要。”

“但是，并非所有接受过疫苗接种的人都会受到相同程度的保护。大约百分之五的疫苗接种者中的一部分不会对乙肝病毒产生免疫力。这意味着他们仍然可以感染，包括慢性感染。

“如果没有适当的治疗，慢性乙型肝炎病毒会导致严重的并发症，包括肝癌，肝硬化和慢性肝功能衰竭。至关重要的是，我们要尽可能地预防此类感染。

“我们希望，通过我们的发现，我们可以利用mNK的抗病毒特性来开发新的治疗方法和改进疫苗，从而使每个人都免受这种病毒的侵害。”

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该研究发表在Gut：https://gut.bmj.com/content/early/2020/03/29/gutjnl-2019-319252