Cell Biology and Biotechnology: Novel Approaches to Increased Cellular Productivity, pp35-61,1993.

Production and Characterization of Immunoglobulin production Stimulating Factor II derived from Namalwa cells.

Hiroki Murakami, Takuya Sugahara, Sanetaka Shirahata, and Koji Yamada


Immunoglobulin production stimulating factor (IPSF) IIwas purified from Namalwa cell lysate by ammonium sulfate precipitation, hydrophobic interaction chromatography and gel filtration. The purified IPSF was estimated a 106 KD protein which was composed of a polypeptide of 40 KD and two polypeptides of 33 KD by gel filtration and SDS polyacrylamide gel electrophoresis. The 33 KD protein extracted from SDS polyacrylamide gel showed IPSF activity, but not the 40 KD protein. The IPSF activity was fairly stable in alkaline but unstable in acidic solution. In a serum-free medium, the IPSF-II stimulated IgM production of human-human and mouse-mouse hybridomas 4-15 and 2-fold, respectively. However. IgG production of neither human nor mouse was stimulated by the factor in the same serum-free medium.