Two studies reveal complex communication between nervous system and immune system

Release date: 2020-01-06 Views: 0

Source: Biovalley

After inhaling the flu virus after vaccination, the body produces a lot of antibodies against the virus, thanks to deep-rooted memories in the immune system. Scientists now find that this response relies heavily on the complex biological dialogue between the immune system and the central nervous system.

In a new study, researchers from the Feinstein Institute of Medical Research have revealed that the immune system and nervous system are interdependent in responding to any form of vaccination. It has long been known that mammals store memories in the nervous and immune systems. To investigate whether these two systems work together in response to invaders-foreign antigens-marks a new direction of scientific research. Related research results were recently published on the preprint server bioRxiv, and the title of the paper was "Antibody responses to immunization require sensory neurons".

Three-dimensional picture of the influenza virus. Picture from Center for Disease Control.

In this new study, led by Dr. Kevin Tracey, the researchers found that antibody responses to vaccination require sensory neurons. As a result of their research, Tracey and his team have proposed that there are effective synergies between these two complex biological systems, thereby providing a compelling new perspective that gives us a glimpse into an area that has almost never been involved .

"The nervous system and immune system have many similar molecules and receptors," Tracey said. He noted that other teams of scientists have also begun to realize how the two systems depend on each other.

Tracey said, "Multiple research teams are studying how these two systems interact. For example, for decades, we have studied how acetylcholine, a typical neurotransmitter produced by neurons, is also produced by T cells, a typical Immune cells); in the presence of acetylcholine, monocytes express acetylcholine receptors to inhibit cytokine production. We believe this discovery may be a new mechanism for the 'dialogue' between the nervous system and the immune system. "

For the first time, Tracey and his colleagues discovered that sensory neurons are required for antibody responses. They also found that activating these neurons increased the production of antibodies.

The paper's first author, Dr. Aisling Tynan, said the discovery adds a new dimension to understanding the vaccination process. Tynan said, "At present, most people will receive multiple booster vaccinations to achieve complete immunity. By exploring the neuromodulation of this process, we may be able to increase the success and effectiveness of vaccination." However, Tynan noted that even After receiving the recommended dose of vaccination, complete immunization may still be difficult to achieve.

A shocking unexpected finding from this new study is that the immune system response is controlled by neurons responsible for sending pain signals. Tracey and his team also found that if these neurons were destroyed, inflammation became widespread, leading to inflammatory diseases.

The researchers performed studies on animal models, focusing on a particular population of neurons, more accurately known as sensory neurons that express TRPV1.

Tracey said, "TRPV1 neurons are usually pain-sensing neurons that recognize heat and various harmful stimuli throughout the body, including the skin, joints, and gastrointestinal tract. This is a surprising discovery: these neurons ... also Antibodies are being produced and regulated. "He added," Isacc Chiu and Cliff Woolf of Harvard Medical School have found that sensory neurons are involved in regulating inflammation during infections and in diseases such as psoriasis. Our finding is that they also regulate immunity, which is very costly People are surprised. "

In early December 2019, Dr. Chiu proposed that it is time to expand understanding of how the nervous and immune systems work together. The nervous system is more than a watchdog that detects danger and alerts the body. Chiu said the nervous system is an active participant in fighting infections.

Chiu and colleagues in a paper published in the Cell journal confirmed that in experimental mice suffering from potentially fatal Salmonella infection, the nervous system works better with the immune system against the bacteria. Neurons regulate the cell channels called microfold cells (M cells) that surround the neuronal Peyer's collecting lymph nodes. These cell channels determine whether microorganisms enter and exit the small intestine. Neurons also promote the presence of protective gut bacteria.

Tynan details the findings of her research team, highlighting how these findings can provide new insights into the adaptive immune system, one of two immune systems.

Technically, many species, including humans, have two types of immune systems: the innate immune system and the adaptive immune system. The innate immune system is the immune system that exists at birth and is the body's first line of defense against invasive organisms that cause infections. The innate immune system includes physical barriers such as the skin and mucous membranes. But there are some cells that resist infection, such as macrophages that can invade invaders.

Although the innate immune system can destroy invaders, it lacks "memory", that is, the intruder must remember its mechanism when it invades again. Without this ability, the body cannot respond quickly when the pathogen is reinfected.

The adaptive immune system, also known as the adaptive immune system, develops over time. When reinfected with foreign antigens, it "remembered" that it had encountered such invaders in the past. Memory T cells are part of the adaptive immune system. They quickly attack such intruders in swarms based on the "memory" of past infections. When re-exposed to foreign antigens, memory B cells produce a strong immune response, which in turn produces a large number of antibodies against invading antigens.

Tracey and Tynan said that the basis of this adaptive immune response is the communication between specific components of the central nervous system.

Tynan said, "This study shows that sensory neurons play a key role in generating specific antibody responses. This is the first time we have been able to confirm the interaction between the nervous system and the adaptive immune system. Further research by our research team is expected Fully expand the role of neurons in the entire process of adaptive immune response. "


1.Aisling Tynan et al. Antibody responses to immunization require sensory neurons. BioRXiv, 2019, doi: 10.1101 / 860395.

2.Nicole Y. Lai et al. Gut-Innervating Nociceptor Neurons Regulate Peyer's Patch Microfold Cells and SFB Levels to Mediate Salmonella Host Defense. Cell, 2019, doi: 10.1016 / j.cell.2019.11.014.

3.Eavesdropping on intimate 'crosstalk': Communication between immune and nervous systems in vaccination

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