Two teams of researchers report that they have used stem cell technology in mice to 'grow' a thymus - an organ that is a vital part of the immune system. The thymus produces cells that fight infections, but becomes less effective with age, or because of attacks by viruses such as HIV (human immunodeficiency virus), chemotherapy treatment, or genetic abnormalities.
The thymus has two main parts - lymphocytes and the epithelium. It was already known that a certain type of stem cell - haemopoetic stem cells - developed into lymphocytes. Now, the researchers, one team from Monash University Medical School in Melbourne, Australia, and the other from the University of Edinburgh's Centre for Genome Research, Scotland, claim that they have identified 'thymic epithelial cells', which grow into the other part of the small organ.
From Monash, Jason Gill and Richard Boyd say that they have grown thymus organs in a number of mice and, because there are strong similarities between the immune systems of mice and humans, suspect that similar results could be achieved in humans. Their work was published in the journal Nature Immunology.
The Edinburgh team published its research in the journal Immunity. Clare Blackburn, the team leader, said that the team had identified a 'unique type of stem cell - a thymic epithelial progenitor cell - which can grow into a functioning thymus'. The cells can be grown in culture and then implanted into mice, where they produce new thymus tissue. The team intends to begin to study whether the same approach would work in humans within a few months.