The major technical problem which needs to be overcome when attempting to transplant organs from pigs to humans is that of hyperacute rejection. The recipient's body immediately detects that the new organ is foreign and attacks it, turning it into a black, lifeless lump within minutes.
Dr Sandrin and his group have adopted a two pronged strategy to overcome hyperacute rejection, both arms of which involve removing sugars from the surface of pigs' cells.
Dr Sandrin has identified the trigger of hyperacute rejection. This is a sugar called GAL, which is found on the surface of all pig cells. So the Australian team are trying to produce a pig which doesn't make GAL.
The second prong of the attack is to try to develop a pig which has O type blood. Blood type is determined by sugars on the surface of red blood cells. If A, B or AB blood is given to someone incompatible a harmful immune response is triggered. However, O type blood carries no sugars and so is the universal donor.
Eventually Dr Sandrin and his colleagues would like to produce a pig with both sugars deleted - one with O type blood and no GAL. Organs from such a pig should be suitable for transplantation into any recipient.
The Australian team is attempting to tackle hyperacute rejection from its origin by removing the trigger. This contrasts with the approach of British and American scientists who have been trying to intervene at the next stage by halting the process of rejection once it has started. Dr Sandrin thinks that ultimately it may be advantageous to combine both approaches.
Dr Sandrin hopes that using his approach, pig-to-human transplants could become a reality within the next five years.
Notes:
1. This strategy differs from the approach of some British and American
scientists who are developing donor pigs by adding human genes.
2. Dr Sandrin will be speaking in the Transplantation Biology session on Thursday 4 December. The BSI 5th Annual Congress will be at the Brighton Centre, Brighton, UK from 2-5 December.
3. Dr Sandrin can be contacted at the Austin Research Insitute, Studley Road, Heidelberg, Victoria 3084, Australia. Tel: +61 3 9287 0666 Fax: +61 3 9287 0600
4. There will be a press office at the meeting in operation from 9am on Tuesday 2 December. Tel: +44 1 273 724 320 / 0378 406 416. Journalists are welcome to attend but are asked to contact Kirstie Urquhart in advance to register. 5. Before the meeting Kirstie can be contacted on +44 181 875 2402 / kirstie@immunology.org