7781
The studies described here characterize an in vitro model using an epithelial cell line ( A549 ) or differentiated epithelial tissue ( MucilAir (TM) ) .
 None
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities:  
Answer:
 None