15364
Lead ( Pb ) is known to increase MHC - II surface expression on murine peritoneal macrophages ex vivo at concentrations exceeding 25 mu M .
 Chemical: Pb
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: Pb