Latest research: It is expected to "crush" cancer-causing viruses in the cradle and "upgrade the navigation" of the immune system

The human body contains about 500 lymph nodes, and circulating lymphocytes constantly pass through these immune hubs to check for antigens that arrive through the lymph fluid. You can imagine that our body is like a busy city. Lymphocytes are like couriers in the city. Their job is to deliver important immune information to help our body fight viruses and bacteria; lymph nodes are like courier centers where lymphocytes need to hand over information to fight invaders together.

To better understand the significance of the latest research below, we need to first understand the classification and role of lymphocytes. Lymphocytes are mainly divided into two categories: B cells and T cells, each of which has different responsibilities.

B cells

1. Antibody production: The main function of B cells is to produce antibodies, which can specifically bind to antigens on the surface of pathogens (such as bacteria and viruses), thereby marking these pathogens for elimination by other immune cells, or directly neutralizing the toxicity of pathogens.

2. Immune memory: Once B cells encounter a specific pathogen, they form memory cells. These memory B cells can respond quickly when they encounter the same pathogen again, producing large amounts of antibodies, thereby clearing the infection faster.

3. Antigen presentation: Some B cells can also act as antigen presenting cells, displaying antigens to T cells, thereby activating T cell-mediated immune responses.

T cells

1. Cell-mediated immune response: T cells kill infected cells by directly contacting them. Killer T cells are able to recognize and kill infected cells and cancer cells.

2. Immune regulation: Helper T cells help activate other immune cells, including B cells and killer T cells. They do this by releasing cytokines, which are small protein molecules that can regulate immune responses.

3. Immune memory: Like B cells, T cells can also form memory cells, which can rapidly proliferate and differentiate into effector T cells when infected again, thereby accelerating the immune response.

4. Regulatory T cells: This type of T cell (also called CD8+ T cell) helps control the intensity and duration of the immune response and prevents excessive immune response, which is very important in maintaining immune homeostasis and avoiding autoimmune diseases.

In simple terms, lymphocytes "patrol" the body through the blood circulation, looking for and destroying bacteria and viruses. They also gather in lymph nodes and other lymphatic tissues, which are the main places where immune cells communicate and activate immune responses. Through these complex and coordinated actions, lymphocytes help protect the body from infection and quickly recover after infection.

Normally, lymphocytes rely on a specific "navigation system" to find lymph nodes. However, when our body is inflamed, this system fails. So, what "signals" do lymphocytes rely on to find lymph nodes when inflamed?

With this research purpose in mind, the researchers discovered a new "navigation signal" called Ch25h. This signal is produced by vascular endothelial cells, while follicular dendritic cells produce another molecule, Cyp7b1. These two molecules work together to provide lymphocytes with a new "navigation map" to help them find lymph nodes during inflammation.

At the same time, the researchers also found a signaling molecule called CCL19. In inflamed lymph nodes, the expression of CCL19 remained unchanged, while another signaling molecule called CCL21 decreased. This suggests that in the case of a decrease in CCL21, CCL19 can compensate for this loss and help lymphocytes enter the lymph nodes during infection.

Overall, this study reveals how lymphocytes rely on a new signaling system to enter lymph nodes when the body is inflamed. These findings have important implications for understanding how the immune system works and for developing new treatments.

What new ideas does this research provide to the medical community?

1. Revealed the adaptability of the immune system in an inflammatory environment

The traditional view is that lymphocytes rely on a specific chemokine receptor-ligand system to enter lymph nodes. However, this study shows that in an inflammatory environment, this system is no longer the main guiding force. New signaling systems, such as Ch25h and CCL19, play a key role in the homing of lymphocytes. This discovery changes our understanding of how the immune system responds to inflammation and provides new ideas for the development of new immunotherapy methods.

2. Provides new potential targets for the treatment of chronic inflammation and tumors

"Chronic inflammation underlies many diseases, including autoimmune diseases, cardiovascular diseases, and tumors. This study suggests that Ch25h and CCL19 may play an important role during chronic inflammation. By modulating the expression or function of these molecules, we may be able to develop new therapeutic approaches for the treatment of these diseases."

3. Provides new ideas for the development of new immunotherapy drugs

The researchers could use the data from this trial to design new drugs that mimic the functions of Ch25h and CCL19 to promote the homing of lymphocytes in inflammatory environments. Such drugs could help boost the immune system's response and improve resistance to infection and tumors.

4. Provides new clues for studying other aspects of the immune system

Researchers can further explore the role of Ch25h and CCL19 in other types of immune cells, as well as their roles in other processes of the immune system. Such studies may reveal new mechanisms of the immune system and provide more opportunities for the development of new immunotherapeutic approaches.

References:

Chen KY,De Giovanni M,Xu Y,et al.Inflammationswitches the chemoattractant requirements for naive lymphocyte entry into lymphnodes.[J].Cell, 2024 Nov 3; [Epub ahead of print].