Immune cells cooperate to prey on bacteria

Just like spiders catch prey, our immune cells also cooperate to catch and "eat" bacteria
.
According to a study published in the journal "Science Advances" on the 11th, researchers from the Vanderbilt University Medical Center in the United States have discovered a new antibacterial mechanism of immune cells, which helps to develop new strategies against Staphylococcus aureus and other pathogens

It is known that neutrophils (first responding immune cells that migrate to the site of infection) can self-destruct and release their proteins and DNA, thereby generating neutrophil extracellular bactericidal networks (NETs)
.
This time, the researchers found that NETs can enhance the bactericidal ability of another type of immune cell-macrophages

"Neutrophils produce'spider webs' that fix bacteria, and macrophages are'spiders' that engulf and kill bacteria,
" said Dr.
Eric Scarlet, one of the researchers

Both neutrophils and macrophages are phagocytes, which can swallow bacteria and produce antimicrobial peptides to fight infection
.
Skar said that the formation of NETs is accompanied by the death of neutrophils.

Researchers have studied the biological functions of NETs in animals and in vitro model systems
.
They found that under the condition of isolating macrophages, the increase in NETosis did not provide neutrophils with a killing advantage

Skar said that macrophages eventually not only have their own antibacterial library, but also have an antibacterial library of neutrophils, which together kill bacteria
.

Increased NETosis will also promote macrophages to kill other bacterial pathogens such as Streptococcus pneumoniae and Pseudomonas aeruginosa
.
The results of the study indicate that the neutrophil/NET-macrophage synergy is a widely used immune defense mechanism

Studies have also shown that eliminating a nuclease that can cut DNA in Staphylococcus will make it more sensitive to the killing of NET-macrophages
.
This is because bacteria have evolved the function of secreting nucleases, which can "kill" a way out of the web-cut off the "cobweb" and escape

At present, drugs related to antibacterial mechanisms are focused on killing bacteria directly rather than reducing their virulence.
This discovery may provide new ideas for the development of new antibacterial drugs
.

Editor-in-chief

Bacteria, fungi, viruses and other microorganisms are everywhere.
Although they are small in size, they can sometimes even bring fatal risks to humans
.
However, in many cases, our body can resist the invasion of these microorganisms, or learn to coexist with them, thanks to the important barrier function of the immune system