Induction of anamnestic T cell proliferation by antigen-pulsed, bone marrow-derived macrophages.

Bone marrow-derived macrophages (BMM phi) were grown in a liquid culture system in the presence of L cell-conditioned medium as a source of colony-stimulating factor. After a 4-h pulse with antigen, cultured irradiated BMM phi were capable of presenting the antigen to primed T cells as assessed in a T cell proliferation assay. Proliferation was optimal when BMM phi were used between days 5 and 8 of bone marrow cell culture. T cells of Lyt1 and Lyt123 phenotype had to be present at the start of the culture period to yield an optimal response. Conventional antisera and monoclonal antibodies directed against the H-2 I region and the I-A subregion, respectively, proved inhibitory in this system. Cultured BMM phi from low-responder strains failed to present antigens under immune response gene control in a form that was immunogenic to T lymphocytes. Cultured BMM phi might thus serve as a source of antigen-presenting cells in the study of cell-cell interaction and immune response gene regulatory mechanisms.