Sericin Protein Derived from Silk Accelerates Proliferation of Mammalian Cells

Abstract

The hybridoma cell line 2E3-O was so well adapted to serum-free ASF103 medium (Ajinomoto, Japan) that the growth rate of the culture in the serum-free medium was more rapid than that in media supplemented with FBS. Although it was so well adapted, the growth of the hybridoma in the serum-free medium was stimulated in the presence of sericin protein, which was derived from silkworm cocoons. In comparison to bovine serum albumin (BSA), one of the best supplements for serum-free media, sericin had an equivalent effect on the growth rate and monoclonal antibody production of the hybridoma cells cultured in BSA-free medium ASF104. Sericin also accelerated the proliferation of rabbit cornea RC4 and mouse fibroblast BALB 3T3 A31 cell lines. Although heating easily denatures and inactivates most proteins, the mitogenic activity of sericin was not affected by autoclaving, which is a more convenient and effective sterilizing technique than filtration. Since BSA is obtained from bovine serum and therefore the risk of infection such as bovine spongiform encephalopathy (BSE) cannot be avoided, sericin derived from silkworm cocoons would be a preferable supplement for culture medium.