Cytotechnology, 5, 255-263, 1991.[PubMed 1367378]
Purification of Immunoglobulin Production Stimulating Factor II-ƒ¿ derived from Namalwa Cells.
Takuya Sugahara, Sanetaka Shirahata, Koji Yamada, and Hiroki Murakami
An immunoglobulin production stimulating factor (IPSF) in human lymphoblastoid Namalwa cells was purified by the serial use of ammonium sulfate fractionation, hydrophobic interaction chromatography and gel filtration, and named IPSF-IIƒ¿. IPSF-IIƒ¿ was estimated as a 112 KD protein composed of a 40 KD polypeptide and two 36 KD polypeptides. The 36 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 and heat-unstable. In a serum-free medium, IPSF-IIƒ¿ stimulated IgM production of human-human and mouse-mouse hybridomas 4-15 and 2-fold, respectively, although its growth stimulatory effect on hybridomas was negligible. The factor stimulated IgG production of neither human nor mouse hybridomas in the same serum-free medium. These results suggested that IPSF-IIƒ¿ was a new cellular factor for stimulating IgM productivity of hybridomas.