I have been purifying IgG1s from hybridoma culture supernatants. These hybridomas have been producing partially reduced artifacts, the most common being IgG1 missing a single light chain (HHL) along with the full intact IgG1 (HHLL). I know these are disulfide variants due to the molecular weight of the reduced vs non-reduced SDS-PAGE. The non-reduced gels of HHL artifacts run around 125kd and the intact molecule (HHLL) runs at 150kd; however, the reduced SDS-PAGE of both shows no difference in MW with heavy chain at 50kd and light chain at 25kd. I've thought of expressing the hybridomas on an orbital shaker to increase O2 levels or even adding copper sulfate. Is there a common practice to prevent hybridomas from producing these partially reduced antibody artifacts?