The researchers then infused the cells captured by class II and III antibodies into mice that had been specially bred to lack an immune system. The cells traveled to the thymus, where they were trained to produce different families of T lymphocytes, each of which was genetically programmed to attack a specific target. Half of the mice that received cells selected with class III antibodies produced sjTRECs compared with 14 percent of mice transplanted with cells selected using the class II antibody.

"These findings show that the thymus of mice that got class III antibody stem cells were able to produce T lymphocytes quicker than mice receiving class II antibody stem cells," Barfield noted. "This suggests if we harvest CD34+ cells using class III as well as class II antibodies we are likely to get better results when we transplant them into children." The results also suggest that the time from transplantation to a fully restored immune system might be reduced using this strategy.

The St. Jude team said that more studies are needed to confirm this initial finding and to translate it into better treatment for children. "Such information will help clinicians rethink how they can do bone marrow stem cell transplantation so that the risk of infection is lowered in their patients," Barfield said.

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Contact: Bonnie Kourvelas
bonnie.kourvelas@stjude.org
901-495-4815
St. Jude Children's Research Hospital
7-Dec-2006