"Natural antibiotic" cloned

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"Natural antibiotic" cloned

A POWERFUL human protein that destroys pathogens by depriving them of the iron they need to grow has been cloned, expressed and purified by UB biologists. Recombinant lactoferrin has potential for many products, including an antimicrobial agent, food preservatives and an improved infant formula.

At the first sign of infection, white blood cells release lactoferrin, which fights bacterial invaders by depriving them of the iron critical to their growth. "Lactoferrin's high affinity for iron makes it a key player in the human immune system," explained Darrell Doyle, professor of biological sciences at UB who directed the research. "It's a natural antibiotic."

Unlike currently available antibiotics, each of which is designed to combat a specific type or group of bacteria, lactoferrin is nonspecific. "Over time, bacteria being treated with antibiotics, such as penicillin or streptomycin, can evolve strains that are resistant to specific characteristics in those drugs," explained Marian L. Kruzel, president of FerroDynamics of Houston, which funded the research. But human lactoferrin binds to the iron of all pathogens. "Without iron, pathogens cannot survive," Kruzel said.

Previous efforts to clone a full-length lactoferrin gene proved difficult, said Kruzel, because of the large fragment of DNA that had to be expressed. The UB team was successful when Paul Gollnick, assistant professor of biological sciences, and Tomasz Kurecki, senior research support specialist, used the PCR (polymerase chain reaction) method to clone the full-length human lactoferrin gene.