The re-arranged VDJ gene segment isolated from the CRIa hybridoma R16.7 was fused to a Cmu gene segment obtained from a BALB/c genomic clone. Four transgenic founders were reported. most initial work was done on lines 5 and 33 while lines 23 and 35 were only studied to a limited extend. Line 5 was used in at least one subsequenty paper. Line 5 contains about 50 copies of the insert. (J:132265)