Patent ID: 7803616

Claim:
A method of culturing animal cells, comprising the steps of culturing animal cells using a medium for animal cell culture to grow said animal cells, wherein the medium for animal cell culture comprises: a basal medium composition for animal cell culture; and sericin comprising at least a polypeptide consisting of the amino acid sequence of SEQ ID NO: 2 or a sericin derivative comprising at least a polypeptide consisting of the amino acid sequence of SEQ ID NO: 1 as an essential region, or at least a polypeptide consisting of a modified amino acid sequence of SEQ ID NO: 2 in which one or more amino acid residues are conservatively substituted wherein the sericin or the sericin derivative is mixed with the basal medium and wherein the growth of the animal cells is stimulated by the sericin or the sericin derivative.