1889
The effects of prostaglandin E2 ( PGE2 ) on cytokine production and proliferation of the CD4+ human helper T cell clone SP-B21 were investigated.
 cell line: CD4+ human helper T cell clone SP-B21; protein: prostaglandin E2; protein: cytokine; protein: PGE2
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
 Entities: CD4+ human helper T cell clone SP-B21, prostaglandin E2, cytokine, PGE2 
Answer:
 cell line: CD4+ human helper T cell clone SP-B21; protein: prostaglandin E2; protein: cytokine; protein: PGE2