Characterization of a transmissible growth-promoting agent derived from CSF of schizophrenic patients which is active on human neuroblastoma cells.

A growth-promoting agent for the human neuroblastoma cell line SK-N-SH(EP) (SH-EP) has been detected in human cerebrospinal fluid (CSF) derived from schizophrenic patients. Following treatment with the CSF, a number of properties of the SH-EP cells changed permanently. These included an accelerated rate of growth, an increased cell density at confluence, a change of cell shape, and an increased ability to form colonies in soft agar. All of these changes are consistent with further cellular transformation of the SH-EP cells. Once the cells' properties had changed following CSF treatment, the growth-promoting activity was found to be present in freeze-thawed cell extracts and in the culture medium, and could be passed to untreated SH-EP cells. The activity could be detected in culture media diluted as high as 10(8). It was inactivated by proteinases, chloroform, or heat but passed through a 0.22-micron filter. The growth-promoting activity can be banded on a Percoll gradient, suggesting that it is particulate rather than a soluble growth factor.