Lymphoma Models for B Cell Activation and Tolerance Iii. Cell Cycle Dependence for Negative Signalling of Wehi-231 B Lymphoma Cells by Anti-u

It has becom e increasingly apparen t that B lymphomas provide clonal models for antigen-specific lymphocytes and for the analysis o f both positive and negative signalling in B cells. In addit ion, ant i Ig reagents have been used to mimic an t igen / to le rogen in their interact ion with B cell receptors at a polyclonal level (1-3). We have been studying the effects o f ant i-Ig on a g roup o f unique B cell lymphomas as models for e i ther tolerogenic or immunogen ic signalling (4-6). One such line, WEHI-231 , has been shown (7, 8) to be readily inhibited in its growth by ant i Ig reagents . We conf i rmed the sensitivity o f this line to growth inhibition by anti-u and anti-K reagents , and de te rmined its kinetics, specificity, and site o f the block in the cell cycle at the G1/S interface (4). In this repor t , we have enr iched WEHI-231 lymphoma cells at various points in G1 to S and analyzed the effects o f anti-# on progression th rough S phase. O u r data suggest that critical events occur early in GI and are uniquely sensitive to modula t ion by anti-~. These studies now will allow sensitive molecular approaches towards an unders tanding of B cell signalling, as well as methods to regulate lymphoma growth per se.