8843
This pro-IL-16 is subsequently processed to the mature cytokine of 13 kDa .
 13 kDa, pro-IL-16
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
Answer:
 13 kDa, pro-IL-16