Control of in-vivo differentiation of myeloid leukemic cells--V. Regulation by response to antigen.

Regulation of in-vivo differentiation of myeloid leukemic cells by response to antigen was analysed with different clones of mouse myeloid leukemic cells and human myeloid leukemic cells (HL-60). Differentiation was studied in diffusion chambers implanted into the peritoneal cavity of mice and the antigens used were bovine serum albumin and chicken ovalbumin. It is shown that the presence of either of these antigens in the diffusion chambers can induce differentiation in MGI+D+ mouse and human myeloid leukemic cells, and that pre-immunization with antigen enhanced this in-vivo differentiation. This enhancement showed immunological specificity and was transferred from immunized to non-immunized mice by spleen cells enriched for T lymphocytes. In contrast to these results with MGI+D+ clones of myeloid leukemic cells, clones of WEHI-3B myeloid leukemic cells were induced to differentiate in vivo to the same extent either in the presence or absence of antigen. The results indicate: that in-vivo differentiation of MGI+D+ clones of myeloid leukemic cells can be induced by response to antigen and that in-vivo differentiation of different clones of myeloid leukemic cells can be regulated in different ways.