[Study on the antitumor activity of CBMC activated by IL-12 alone or in combination with IL-2].

OBJECTIVE

To investigate the efficacy of cord blood mononuclear cells (CBMC) activated by interleukin-12 (IL-12) alone or in combination with interleukin-2 (IL-2) in tumor cells.

METHODS

The cytotoxicity of CBMC and peripheral blood mononuclear cells (PBMC) activated by IL-12 and/or IL-2 was measured with (3)H-TdR release assay, and the morphological change of K562 cells incubated with activated CBMC was observed.

RESULTS

(1) CBMC activated by 10 IU/ml IL-12 produced significant cytotoxic activities which were (27.23 +/- 4.92)% and (29.12 +/- 3.46)% against K562 and Raji cells, respectively; moreover, 10 IU/ml IL-12 could be synergized with the same dose of IL-2 in enhancing the cytotoxicities which were (47.60 +/- 4.60)% and (38.69 +/- 4.86)% against the two target cells, respectively. (2) Short-term incubation with IL-12 activated CBMC increased the cytotoxicity to K562 cells, and long-term incubation increased the cytotoxicity to Raji cells. (3) No NK lytic activity of CBMC could be detected before cytokines stimulation. After stimulated by 10 IU/ml IL-12, NK lytic activity of CBMC was similar to that of PBMC. (4) K562 cells demonstrated obvious apoptosis after cultured with activated CBMC.

CONCLUSION

CBMC activated by IL-12 had evident antitumor activity, which was further increased when IL-12 in combination with IL-2. These results showed the potential value to improve the graft-versus-leukemia (GVL) response after cord blood progenitor cell transplantation.