Idiotype-specific T cell suppression of light chain mRNA expression in MOPC-315 cells is accompanied by a posttranscriptional inhibition of heavy chain expression.
Earlier studies have shown that idiotype-specific T suppressor cells can directly inhibit the biosynthesis and subsequent secretion of immunoglobulin from the BALB/c myeloma, MOPC-315. This suppression is highly specific and does not affect nonimmunoglobulin protein synthesis in these cells. The selective character of this suppression suggested a transcriptional or translational mechanism of control. Therefore, we analyzed suppressed MOPC-315 cells for the expression of light and heavy chain mRNAs. Since the events that occur in a B cell subsequent to reception of suppressive signals from T cells are presently unknown, these experiments address a fundamental aspect of B cell regulation. Another important aspect of these studies is that they deal with a suppressor T cell that clearly operates directly upon the antibody-secreting cell. This system involves regulation of a B cell differentiative function without influencing the B cell clonal size. We have employed the trinitrophenyl (TNP)-specific myeloma, MOPC-315, because it provides a source of monoclonal B cells which in earlier studies have been shown to be responsive to idiotype-specific and TNP-antigen-specific immunoregulatory signals. The idiotype-specific T cells were generated by hyperimmunizing BALB/c mice with the myeloma protein bearing the 315 idiotype, in complete Freund's adjuvant. Poly A+ mRNA was isolated from MOPC-315 cells following coculture with either normal or idiotype-immune T cells. The mRNA was analyzed using hybridization techniques and cDNA probes specific for alpha or lambda 2 light chain constant regions.(ABSTRACT TRUNCATED AT 250 WORDS)
D000818:Animals; D007143:Immunoglobulin Heavy Chains / Q000096:biosynthesis; D007130:Immunoglobulin Idiotypes; D007147:Immunoglobulin Light Chains / Q000096:biosynthesis; D051379:Mice; D008807:Mice, Inbred BALB C; D010954:Plasmacytoma / Q000276:immunology / Q000378:metabolism; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000378:metabolism*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
D007143:Immunoglobulin Heavy Chains; D007130:Immunoglobulin Idiotypes; D007147:Immunoglobulin Light Chains; D012333:RNA, Messenger