ENDOPLASMIC-RETICULUM PROTEIN EXPRESSION IN RECOMBINANT NS0 MYELOMAS GROWN IN BATCH CULTURE

During batch growth of two recombinant NSO myelomas, an increase in th e expression of the endoplasmic reticulum (ER) proteins (GRP78/BiP, GR P94, and ERp72) was observed. A marked increase in these proteins was associated with the decline phase of growth, an increase in the produc tion rate of chimeric antibody, and a marked slowing or halt in the up take of glucose and glutamate. Refeeding with glucose, glutamate, or a mixture of amino acids just prior to the onset of decline phase faile d to repress induction. Although refeeding with glutamate led to an in crease in specific productivity, there was no significant difference i n the pattern of ER protein induction. These results indicate that an increase in ER protein expression is not solely related to productivit y but also to certain changes that occur during the course of batch gr owth. (C) 1996 John Wiley & Sons, Inc.