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In the present study, we have utilized a mutant Jak1 -deficient HeLa cell line , E1C3 , and its parental Jak1 -expressing counterpart , 1D4 , to analyze the role of Jak1 in mediating IL-4-induced tyrosine phosphorylation events.
 E1C3, parental Jak1 -expressing counterpart, Jak1, Jak1, 1D4, Jak1, mutant Jak1 -deficient HeLa cell line
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:
 E1C3, parental Jak1 -expressing counterpart, Jak1, Jak1, 1D4, Jak1, mutant Jak1 -deficient HeLa cell line