Carrero relishes the discovery aspect of science

In Javier Carrero’s native Puerto Rico, it’s expected that intelligent people will become a doctor, lawyer or engineer.

Not that he’s a rebel, but after graduating with a bachelor’s degree in biology from Emory University in 1996, Carrero spent the next two years in the information technology community in Atlanta.

Javier Carrero (left) works in a lab with postdoctoral researcher Boris Calderon, M.D.
Javier Carrero (left) works in a lab with postdoctoral researcher Boris Calderon, M.D. “The shining diamond of St. Louis really is Washington University,” Carrero says. “It’s one of the pillars of institutional learning in the world. I’ve found it to be a very collaborative, collegial environment where egos never get in the way of helping each other out.”

“I’ve loved computers since I was 10 years old, and when I went into IT, the Internet was just booming,” Carrero says. “It wasn’t long, though, before I realized that I missed the intellectual stimulation of research, and that I was far more motivated by the discovery aspect of science than treating patients.”

Carrero returned to San Juan, where he enrolled at the University of Puerto Rico and earned a master’s degree in molecular biology in 1998.

He came to Washington University in 2000 to pursue a doctorate in immunology through the Division of Biology and Biomedical Sciences. In this program, he was matched with one of the world’s masters of pathology and immunology: Emil Unanue, M.D., the Edward Mallinckrodt Professor and chair of the Department of Pathology and Immunology in the School of Medicine.

Carrero became captivated by the workings of the immune system. With Unanue in his corner, he steadfastly proceeded to make exceptional discoveries into the process by which bacterial pathogens elude the sentries of the immune system.

The discoveries have resulted in Carrero being first author of two critical technical papers, and someday could lead to novel drug development against bacterial diseases.

One important Unanue discovery is particularly key to Carrero’s doctoral work: Using the bacterium Listeria monocytogenes, Unanue showed that molecules known as the “major histocompatability complex” display pieces of pathogens on their cell surfaces, alerting one of the body’s chief bug-busters, the T-cells, to spring into action.

Unanue had observed that Listeria infection led to very strong incidences of cell death — called apoptosis — in laboratory mice. Using this as his model, Carrero tried to figure out if the Listeria virulence factor listeriolysin O (LLO) is the culprit in causing cell death, which, in turn, endangers an organism’s health.

In a 2004 Journal of Immunology paper, Carrero, Unanue and WUSTL postdoctoral researcher Boris Calderon, M.D., proved that LLO kills T-cells and described the process.

That same year, in a Journal of Experimental Medicine paper, the trio found that mice genetically engineered to be deficient in the immunologically important Type I interferon receptor were actually resistant to Listeria infection. They then inferred that T-cell death was responsible for enhanced mouse susceptibility to Listeria infection.

The surprise was that Type I interferon-deficient mice infected with almost any virus quickly succumb and die, whereas there is protection from bacterial infection.

“We think we have the mechanism for cell death, but we need to iron it out,” Carrero says.

Blocking the pathways involved in cell death might lead to developing vaccinations for people who have a full-blown bacterial infection and possibly a vaccine protocol that would provide better immunity.

“One of the challenges in immunology is developing a protocol that, instead of targeting the generation of neutralizing antibodies, targets the other arm of the immune system — T-cells — to protect during an infection,” Carrero says.

Carrero said that in the future he hopes to focus on new strategies for dealing with infections and come up with new immunity protocols. This could include ex-ploring hunter viruses — nonpathogenic viruses that target other viruses and destroy them.

Carrero defended his doctoral thesis in April and then rewarded himself with a 10-day vacation to Italy, where he indulged in one of his passions — attending the opera.

Graduate School of Arts & Sciences

He enjoys bicycling, reading and going to the symphony.

“There is plenty to do in St. Louis, and a relatively laid-back atmosphere to do it in,” he says.

He comes from a big baseball family and sees several Cardinals games each year.

“I’ve got an uncle who flies in here and makes sure he sees some games,” he says. “Sometimes I wonder, ‘Is he coming here to visit me or see the Cards play?'”

Carrero will seek postdoctoral work at the beginning of 2006 and plans a long career as a teacher and researcher like his mentor, Unanue.

“Javier takes care of ‘cultivating our garden,’ as Voltaire said, but applied here to science,” Unanue says. “That is, for him, his commitment to the day-to-day laboratory work and projects comes first and foremost.

“It has been a real symbiosis working together, sometimes intense and boisterous, perhaps reflecting our common Spanish heritage.”

“Emil is a great mentor,” Carrero says, “the best I possibly could have had. He’s brilliant and a great motivator.

“The shining diamond of St. Louis really is Washington University. It’s one of the pillars of institutional learning in the world. I’ve found it to be a very collaborative, collegial environment where egos never get in the way of helping each other out.”

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