Our immune system has specialized cellular soldiers—like T-cells and B-cells—ready to fightoff bacterial invasions. However, non-immune cells aren’t entirely defenseless. Research publishedin Science in July 2021 found certain proteins literally have a detergent-like ability to wipe outbacteria like a grease stain.
        “This is a case where humans make their own antibiotic in the form of a protein that acts like adetergent,” says study author John MacMicking, an immunobiologist at Yale University, in astatement, “We can learn from that.”
         First, the team infected non-immune cells with Salmonella, a rod-shaped bacteria that affectsthe intestines. Then, they screened the cell’s genes for protective proteins and found a match:APOL3. This protein has parts drawn to water and other parts drawn to fats—just like laundrydetergent. APOL3 attacks the greasy lipids lining the inner bacterial membrane with precision,never mistaking a human cell membrane for the invader.
         As resistance to antibiotics surges, an alternative option is needed. Pathogens may have theirown proteins that interfere with APOL3’s counterattacks, but researchers could design a newantibiotic that targets those pesky proteins so APOL3 can do its thing. The research team alsosuggests designing small molecules that mimic APOL3’s actions using what’s called host-directedtherapy, which creates a harsh environment for the pathogen instead of directly disarming it.
         But first, the scientists have to understand the breadth of infections controlled by APOL3 andother immune defense proteins. “That will incentivize the research effort in tackling importanthuman bacterial, viral, and parasitic pathogens, especially if antibiotic resistance is alreadyprevalent for those microbes and we need new drugs,” MacMicking says via email. “Inventions thatmimic host protein activities are still relatively understudied,” MacMicking explains. “This could befertile ground since our immune defenses are largely indifferent to whether pathogens are currentlysensitive or resistant to known antibiotics.”
【題組】41. Which of the following is the least likely title for this passage?
(A) Human cells harness power of detergents to wipe out bacteria
(B) Human cells use protein to clean up intracellular bacteria
(C) Human cells can generate proteins to ward off bacteria
(D) Human cells can manipulate antibiotic to kill germs