Large Scale Ex Vivo Expansion and Activation of Human Natural Killer Cells for Autologous Therapy
Miller, J.S., S. Klingsporn, J. Lund, E.H. Perry, C. Verfaillie, P. McGlave.
Bone Marrow Transplantation. Macmillan Press Ltd. 1994. 14:555-562.
Immunotherapy with recombinant interleukin-2 (rIL.2) activated natural killer cells (ANK) may be useful in the treatment of malignancies.
Difficulties in large scale cultivation of purified ANK have hampered clinical trials. In a first set of experiments designed to characterize ANK precursors in blood we demonstrated that both FACS purified CDS6+/CD3- and CDS6- /CD3- cultured with rIL•2 give rise to an expanded cell population bearing the CD56+(bright)jCD3-, phenotype and having both NK and lymphokine-activated killer (LAK) activity. Cultivation of NK was markedly enhanced by autologous monocytes.
We next demonstrated that panning of peripheral blood stem cells on CDS/CD8 coated flasks yielded a starting population enriched for monocytes and NK precursors which after cultivation resulted In production of 4 X 1010 highly cytotoxic ANK adequate for in vivo clinical trials.
Finally, we demonstrated that ANK generated in high dose IL•2 maintain NK and LAK activity for up to 6 days when cultured in as little as 1U/ml rIL•2. This may allow infusion of ANK with a rIL•2 dose achievable in vivo that does not produce significant systemic toxicity.
We plan to test the efficacy of ANK to prevent relapse in a minimal residual disease stale following autologous bone marrow transplant.