Adoptive cell transfer refers to the transfer of cells into an organism, which could be a patient or in the case of this cartoon, a mouse. This is a very common technique used in immunology research to understand how the cells behave.
Adoptive Cell Transfer in Immunology Research
Typically, the cells that are being transfer have a different marker than the cells in the host. After being transferred to the new hosts, this marker allows the cells to be distinguished from the host cells. In this cartoon here the marker is CD45.1 and the marker of the host cells is CD45.2. Depending on the application, cells can also be labeled with a dye before being transferred so you can trace them back. An example of such a dye, that is also used to trace cell proliferation, is Carboxyfluorescein succinimidyl ester (CFSE).
If you are curious on some of the applications adoptive cell transfers in immunology research read this article Utilization of CD45.1 as a Marker of Donor Leukocytes in Recipient CD45.2 Mice in a Bone-Marrow Transfer Chimeric Experiment by Biocompare.
Adoptive Cell Transfer for Treating Disease
More recently, adoptive cell transfers have also been used to treat disease in humans. As an example, cells are taken out of a patient, the cells are then ‘re-educated’ and transferred back into the same patient. These now ‘educated’ or ‘activated’ cells can go ahead and perform their function to cure disease. You can read more about how this is applied to treat cancer in the article Adoptive cell transfer as personalized immunotherapy for human cancer published by Science Magazine.