Fig. 1.
SDS-PAGE analysis of recombinant, lymphoma-derived Fab fragments.
Immunoglobulin transcripts from lymphoma biopsies of both patients were amplified by PCR, sequenced, and inserted into pFab.γκ. Recombinant Fab fragments were expressed from pFab.γκ vectors in E. coli. Periplasmic fractions of induced bacteria were prepared and purified by affinity chromatography. The resultant protein eluate was analyzed by standard 12% SDS-PAGE under reducing and nonreducing conditions. Protein bands were visualized by silver staining. The Fd and IgL chains of patient 2 had almost identical migration properties under reducing conditions. Even when the gel was run with 6 mol/L urea, the separation of the bands could not be improved (not shown). SM, high-molecular weight marker.