4069
Taken together, these data suggest that differences in patterns of expression between Spi-B and PU.1 distinguish the function of each protein during development of the immune system .
 protein: PU.1; protein: Spi-B
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: PU.1, Spi-B 
Answer:
 protein: PU.1; protein: Spi-B