Germ cell, genes present/expressed

Weigert et al. (100) have considered possible explanations for the relatively high incidence of myeloma proteins having anti-a(l —3)dex-tran activity and k chains that are apparently identical in structure. They conclude that in the BALB/c mouse the prototype chain (Xo) is controlled by a germ line gene, which is expressed in a relatively large number of precursor lymphocytes. These are stimulated to proliferate by a(l 3)dextran, or closely related molecules, present in the intestinal tract of the mouse. The frequency of appearance of the corresponding myeloma protein is then assumed to be related to the abundance of these clones of cells. 

At present one cell line is available expressing and Cy from one IgH locus [46,47]. Long transcripts containing several CH genes have not been demonstrated directly in these cells. In another cell line the secretion of IgG by switch variants could lead to presentation of passively absorbed IgG on IgM+ cells which have all CH genes in germ-line configuration [48]. 

---