Effect of immunoglobulin production stimulating factors in foodstuffs on immunoglobulin production of human lymphocytes.

cultured under serum-free conditions for the mass production of human MoAbs,S+ Howcver, the Ig productivity ofhuman-human hybridomas has been lewer than that of mouse-mouse hybridornas, especially in serum-t'ree media.6' To enhance the Ig productivity of human-human hybridomas under serum-free conditions, we screened the immunoglobulin production stimulating factor (IPSF), and have found cellular IPSFs in cell extracts of hurnan lung adenocarcinoma PC-8i) and human lymphoblastoid Namalwa cells.6} and in the culture supernaLant of human lymphoblastoid HO-323 celis.S5 We have also screened IPSFs in foodstuffs and found that chickcn egg yolk lipoprotein (YLP), lactoferrin, casein and Royaljeliy had IPSF activity.D] We report here the effect of IPSFs on the Ig production of hurnan lymphocytes. YLP was prepared by the method described previously,iO} and RoyaLjelly was suppled by MoTinaga Seika Co. ERDF mediumS) was purchased frorn Kyokute Seiyaku Co., and t'etal bovine serum (.FBS) from Cell Culture Laboratories. For the serum-free culture of human lymphocytes, ERDF medium supplementcd with