Xcyte Announces Paper on Xcellerated T Cells in CLL

Xcyte Therapies has announced the publication of a scientific paper describing the mechanism of action of its lead product, Xcellerated T Cells, in chronic lymphocytic leukemia (CLL).

The paper, titled "In Vitro Engagement of CD3 and CD28 Corrects T Cell Defects in Chronic Lymphocytic Leukemia," appeared in the Feb. 15, issue of The Journal of Immunology.

In the Xcellerate Process, T cells are activated ex vivo using Xcyte Dynabeads, which are superparamagnetic beads to which anti-CD3 and anti-CD28 monoclonal antibodies have been covalently linked. This results in the upregulation of several receptors on the surface of the T cells. In healthy individuals, T cells and B cells interact with each other through receptors on their cell surfaces. In CLL patients, these receptors are poorly expressed, which prevents these interactions from taking place. This may contribute to the growth of the leukemic B cells. Upon activating T cells from CLL patients with the Xcellerate Process, researchers demonstrated that they could markedly increase the interaction of each patient's T cells with that patient's leukemic B cells.

Further studies showed that this enhanced interaction was a direct result of upregulation of key receptors on the patients' T cells, which stimulated increased expression of receptors on the patients' leukemic B cells. The authors reported that these interactions induced the expression of high levels of a molecule known as Fas on the leukemic B cells. Fas plays a critical role in programmed cell death, which was demonstrated to take place in leukemic B cells when mixed with the patients' activated T cells.