Navigating the Body as an Immune Cell

Jonna Alanko et al. ,CCR7 acts as both a sensor and a sink for CCL19 to coordinate collective leukocyte migration.Sci. Immunol.8,eadc9584(2023).DOI:10.1126/sciimmunol.adc9584

What happens when we get hurt or sick? Our body has to find a way to protect us and make sure we get better. This is done through the action of white blood cells. White blood cells are immune cells. They exist in our blood and fight off dangerous viruses, bacteria, or other threatening invaders in our body. For white blood cells to act on these foreign invaders, they need to be able to move through our body to the site of infection. The question scientists answered through this research is how the cells know where to go and collectively navigate their path through the complex environment that is our body.

To address this question we first have to understand the action of dendritic cells. These cells are constantly searching our body for intruders or infection. If they detect a site of infection, they are “activated” and migrate to an area of the body where other immune cells are present. They, in turn, alert antibodies, the defence cells of our body, to target the specific intruder. This movement of dendritic cells is believed to be carried out by chemicals called chemokines that form a pathway for them to move along. How this pathway is created was addressed in this research paper.

It was believed that these chemokines externally formed a pathway that was detected by receptors on the cells. Receptors are present on the exterior of the cells and bind to chemokines to signal the cells to move along their pathway toward an area of infection or inflammation. However, sometimes the concentration of chemokines reaches a certain threshold and their binding to receptors, specifically a receptor called CCR7, is taken too far. The chemokine is taken into the cell itself. This action can reduce the cell’s sensitivity to chemokines and can put an end to the movement of cells. Through the internalisation of chemokines, cells are actually able to change chemokine concentration thereby controlling their own pathways through the body.

This study shows that self-made paths for immune cells can collectively guide nerve cells throughout the body and can have applications in immunology, development, and cancer research. This new information can create a new understanding of how immune cells communicate and open up more research into similar mechanisms used by other immune cells. Scientists may also use this information to design new strategies to enhance the movement of immune cells to certain areas of the body such as tumours or infection sites.

By Nyrika

Works Cited

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“Receptors- Functions and Types of Receptors - an Overview.” BYJUS, byjus.com/biology/types-of-receptors/. Accessed 11 Sept. 2023.

Science Daily. “Immune Cells Shape Their Own Path.” ScienceDaily, 1 Sept. 2023, www.sciencedaily.com/releases/2023/09/230901143610.htm. Accessed 11 Sept. 2023.

“What Are White Blood Cells? - Health Encyclopedia - University of Rochester Medical Center.” Www.urmc.rochester.edu, www.urmc.rochester.edu/encyclopedia/content.aspx?ContentID=35&ContentTypeID=160#:~:text=White%20blood%20cells%20are%20also. Accessed 11 Sept. 2023.