In an interesting article written by John Hopkins Medicine on March 21, 2025, it becomes apparent to John Hopkins Medicine scientists that bacteria protect themselves from certain phage invaders (viral invaders that replicate themselves within bacteria) by seizing the genetic material from the weakened phages, using it to vaccinate themselves, allowing them to protect themselves from the more intense invaders. In the scientists experiments, they note that the bacteria take advantage of weaker phages known as temperate phages, by stealing genetic material from these phages when they are dormant and form a “memory” of the invader and their offspring as the phage multiplies. Then, the bacteria is able to recognize the invaders and fight them off.
After recognizing the unique response, John’s Hopkins investigators concluded that bacteria used CRISPR-Cas systems to break down phage DNA. These CRISPR systems can only break down DNA that matches a memory, captured from a previous invader. The scientists stated that the CRISPR systems acts as a “recording device” that documents all past invaders the bacteria encounters, and when one returns, the bacteria is ample and able to swiftly rid of it.
To try and understand more about this complex process, the scientists performed an experiment and concluded that the bacteria’s CRISPR system works best against naturally dormant phages as it was during the dormant phase where the bacteria created the memories of the phages.
This study from John Hopkins relates the the immune system unit we learned in AP Bio. The Bacteria’s process of making a homemade “vaccine” is naturally very similar to vaccines humans get like Flu shots. When we get a vaccine the weakened antigen enters the system and the cell-mediated and humoral responses kill the antigen, B memory and T memory cells are created, ensuring that if the same, or a similar antigen enters the body, it is swiftly dealt with. In the instance of the bacteria, the dormant phage is the weakened antigen, which allows the bacteria to create a memory of the phage and therefore be ready to eliminate it next time it enters the bacteria.
There are many implications to this study, one being an advancing in phage therapy an alternative process tp antibiotics that uses phages to target bacterial infections. If scientists make phages that bypass the CRISPR defense, phage therapy will be a lot more effective. As someone who hates to get sick, advancements in treatments to stop bacteria and disease in general always interests me. What do you think the future implications of this study will be?
(picture of phage)
Leave a Reply