The idiotype-specific myeloma transplantation resistance induced in BALB/c mice by immunization with the DNP-binding IgAλ2 protein produced by plasmacytoma MOPC-315 is ablated by post-immunization thymectomy. Sham-thymectomy has no effect. The ablative effect of thymectomy is observed in mice challenged subcutaneously with MOPC-315 cells either 3 days after thymectomy, or after a rest period of 44 days after thymectomy. These observations suggest that short-lived, thymic-dependent suppressive factors may play a role in the idiotype-specific myeloma graft resistance.
This work was supported by Research Grants CA-15306 and CA-17114 and Training Grants GM-00897 and CA-09118 from the National Institutes of Health and a grant from the following companies: Brown & Williamson Tobacco Corporation; Larus and Brother Company, Inc.; Liggett & Myers, Inc.; Lorillard, a Division of Loews Theatres, Inc.; Philip Morris, Inc.; R. J. Reynolds Tobacco Company; United States Tobacco Company; and Tobacco Associates, Inc.