Hybridoma cell cultures continuously undergo apoptosis and reveal a novel 100 bp DNA fragment

This report represents an investigation into the nature of apoptosis in hybridoma cultures and its significance to their utilization in biotechnology. To this end DNA fragmentation and capillary electrophoresis of genomic DNA was studied during the culture of two hybridoma cell lines. This indicated that the phenomenon of apoptosis was always present even under normal culture conditions. Two DNA fragments not associated with the typical DNA fragmentation ladder were identified in the two hybridoma cultures: a previously unreported DNA fragment of about 100 bp and a large fragment which may correspond to one reported in the literature (Walker et al., 1993). The small fragment was identified as soon as the early exponential growth phase of culture, while the large fragment appeared only in the latter part of the growth curve when there was marked DNA fragmentation. In addition we present evidence that aurintricarboxylic acid, which inhibits apoptosis in neural cells, permits this process in hybridoma cells at levels below 100 microM. This unusual predisposition of hybridoma cultures to undergo apoptosis and their response to inhibitor of apoptosis may have important implications for approaches to the culture of hybridomas and their utilization for monoclonal production.