Single gene defect wipes out immune cell development

Researchers at the Wellcome Trust Sanger Institute have identified the key gene in ensuring that our immune defences develop infection-fighting cells. No cells of the adaptive immune system - key to attacking and destroying bacteria and other pathogens - develop in the absence of the gene Bcl11a.

The result will help to understand the human immune system and how it can fail in disease, as well as possibly allowing the development of functioning human immune systems in mice for research and development of treatments.

Our immune system has two arms: the adaptive and innate pathways. The adaptive immune system leads to infection- and cancer-fighting cells called B cells, T cells and NK cells: these all share a common ancestor, or lymphoid progenitor.

The team had shown earlier that Bcl11a was important for development of some immune cells in mouse embryos. In the new research they looked at the role of this gene in adult mice. They knocked out Bcl11a and looked at development of the immune system cells.

They were surprised to see that no cells of the adaptive system developed in the mice.

"This is the cornerstone of building an effective immune system," says Dr Pentao Liu, who led the research. "It is perhaps the first time that anyone has found a single gene that is absolutely essential for development of cells of our entire adaptive immune system.