Deletion of the κ genes from mouse hybridomas established with NS-1 myelomas

Monoclonal antibodies (mAbs) of the IgG class produced by mouse hybridomas raised with NS-1 myelomas have been shown to contain two types of immunoglobulin light (κ) chains derived from the myelomas and antigen-stimulated spleen lymphocytes, and the hybridomas produce three mAb species with light chain heterogeneity (Abe and Inouye, 1993). In the present study, 9 hybridoma lines secreting homogeneous mAbs have been isolated from 63 lines cloned from an established hybridoma line producing three mAbs. They secrete homogeneous mAbs containing light chains derived from either myeloma or spleen cells. They contain either κ gene derived from the respective cells, and the other gene was deleted during the cultivation. The deletion frequency of the κ gene of myelomas is 3 times higher than that of spleen cells, although 80-85% of hybridomas reach the stable state containing both κ genes.