Evaluation of the major royal jelly proteins as an alternative to fetal bovine serum in culturing human cell lines.

Royal jelly (RJ) is a well-known bioactive substance. It contains large amounts of major royal jelly proteins (MRJPs), which express growth-factor-like activity in several animal and human cell lines. However, the question on whether MRJPs possess growth-factor-like activity on all types of cell cultures remains. In order to determine whether MRJPs can be used as an alternative to fetal bovine serum (FBS) in different types of human cell culture, the proliferation of the complex serum with different ratios of MRJPs/FBS (M/F) was evaluated on five cell lines: 293T, HFL-I, 231, HCT116, and Changliver using MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide) assay. The proliferation activity of the combination of the complex M/F serum with cytokines on the test cell lines was also measured. The results demonstrated that the complex serum with M/F 6/4 possessed the highest proliferation activity similar to or in excess of FBS. However, no activity of complex medium with M/F 6/4 was observed in 231 cells, indicating a selectivity of MRJPs on cell types. Compared with the complex medium with M/F 6/4, the complex medium with M/F 6/4 together with two cytokines, epidermal growth factor (EGF) and insulin-transferrin-selenium (ITS), promoted proliferations of Changliver, 293T, HCT116, and HFL-I by 18.73%‒56.19% (P<0.01). Our findings demonstrate that MRJPs could partially replace FBS in culturing many human cell lines.