2947
EL-4 cells were transfected with a plasmid containing the IL-2 promoter and enhancer region linked to the chloramphenicol acetyltransferase ( CAT ) reporter gene .
 CAT, enhancer region, chloramphenicol acetyltransferase ( CAT ) reporter gene, chloramphenicol acetyltransferase, IL-2 promoter, EL-4 cells
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:
 CAT, enhancer region, chloramphenicol acetyltransferase ( CAT ) reporter gene, chloramphenicol acetyltransferase, IL-2 promoter, EL-4 cells