Antigen-specific regulation of myeloma cell differentiation in vivo by carrier-specific T cell factors and macrophages.

Previous studies demonstrated that: i) the TNP-binding myeloma MOPC-315 differentiated during in vivo growth in diffusion chambers (DC) implanted i.p. into normal BALB/c mice, and ii) the myeloma cell differentiation was regulatable by carrier-specific presentation of TNP to MOPC-315 cells in carrier-primed mice. In those studies, promotion and suppression of MOPC-315 differentiation occurred in the presence of carrier-specific helper and suppressor activities, respectively. In the present studies, we demonstrate that carrier-specific regulation of MOPC-315 differentiation can be adoptively transferred to normal mice with carrier-primed T lymphocytes. In addition, the induced regulation of MOPC-315 differentiation is abrogated when macrophages are not present with MOPC-315 cells in the DC. These studies establish the immunologic basis of myeloma cell regulation and suggest that soluble, carrier-specific helper and suppressor factors of T cell origin regulate MOPC-315 differentiation directly or in collaboration with macrophages.