Effects of development of host immunity on the biodistribution of xenogeneic MHC non-restricted cytotoxic T cells: implications for adoptive cell therapy of cancer.

The human MHC non-restricted cytotoxic T cell line TALL-104 has potent anti-tumor effects in dogs with spontaneous tumors. This study was designed to examine the effects of the development of host immune responses on the baseline organ distribution of TALL-104 cells in healthy dogs. 111In-oxine labeled TALL-104 cells (107 cells/kg) were infused systemically in three dogs, either on day 1, 3, or 5 of a 5-day injection cycle; two dogs received two more injections of the labeled cells at monthly intervals, whereas the third dog received free 111In-oxine, 3 months after the first 5-day infusion. Analysis of blood and plasma cell clearances and imaging studies indicated a progressively faster clearance of the cells from the blood and organs after multiple daily injections as well as at the time of each monthly boost when host immune responses against the xenogeneic cells had developed. These findings have important therapeutic implications for the design of effective TALL-104 cell administration schedules in clinical trials.