Regulatory T cells suppress ability to withstand central nervous system injury.

2003 FEB 5 - (NewsRx.com & NewsRx.net) -- "The ability of rats or mice to withstand the consequences of injury to myelinated axons in the CNS was previously shown to depend on the ability to manifest a T cell-mediated protective immune response, which is amenable to boosting by myelin-specific T cells. Here we show that this ability, assessed by retinal ganglion cell survival after optic nerve injury or locomotor activity after spinal cord contusion, is decreased if the animals were immunized as neonates with myelin proteins (resulting in their non responsiveness as adults to myelin proteins) or injected with naturally occurring regulatory CD4(+)CD25(+) T cells immediately after the injury, and is improved by elimination of these regulatory T cells," researchers in Israel report.

"In nude BALB/c mice replenished with a splenocyte population lacking CD4(+)CD25(+) regulatory T cells, significantly more neurons survived after optic nerve injury than in nude mice replenished with a complete splenocyte population or in matched wild-type controls," said Jonathan Kipnis and colleagues at the Weizmann Institute of Science. "In contrast, neuronal survival in wildtype BALB/c mice injected with CD4(+)CD25(+) regulatory T cells immediately after injury was significantly worse than in noninjected controls."

The researchers concluded, "These findings suggest ...