SPONTANEOUS APOPTOSIS IN NS-1 MYELOMA CULTURES - EFFECTS OF CELL-DENSITY, CONDITIONED MEDIUM AND ACID PH

Apoptosis is a form of cell death which plays an important role in man y biological processes including the regulation of B and T lymphocyte functions. We report here the spontaneous development of extensive apo ptosis in cultures of the NS-1 mouse myeloma cell line following overg rowth. The apoptosis was identified by both its ultrastructural featur es and its DNA fragmentation pattern. High cell density and conditione d medium, but not acid pH, were found to be major inducers of apoptosi s in this experimental system.