Enhanced cloning efficiencies of murine hybridomas using human plasma supplemented medium.

Normal human plasma and plasma from patients with chronic lymphocytic leukemia (CLL) were used as growth supplements for the cloning of murine hybridomas. Basal medium, consisting of DMEM with 5% foetal calf serum (FCS) was conditioned with supernatant from a known human IL-6-secreting cell line, BRI-6 (BRI-6-CM), normal human plasma (NHP-DMEM), and plasma from patients with CLL (CLL-DMEM). When compared to conventional feeder layers of macrophages, thymocytes, splenocytes and to feeder CLL cells and BRI-6-CM the numbers of clones formed by growing hybridomas in CLL-DMEM was greatly enhanced with a corresponding increase in the number of antibody-producing clones, as determined by ELISA. NHP-DMEM also enhanced the cloning efficiency. All CM and plasma supplemented medium were examined for the presence of interleukin-6 (IL-6). Of eight CLL plasma samples examined only two had elevated IL-6 levels.