Cell types of the human body can be identified by the molecules they bear on their surface. Human blood stem cells are often characterized by a protein marker they bear
on their surface called
. By coupling a magnetic particle (comprised of iron and dextran, a sugar molecule) to an antibody that is capable of binding very specifically to
the CD34 surface marker, stem cells can be separated from other cells when placed in a magnetic field within the medical device.
The preparation of a T cell depleted graft for transplantation involves a series of steps.
- Collection of blood stem cells from the donor
- Incubation with the anti-CD34 magnetic particle
- Passage through a magnetic field
- Retention of the blood stem cells within the magnetic field, while all other donor cells are removed, including potentially harmful T cells
- Removal of the magnetic field and collection of the highly purified stem cells for transplantation