5336
The IL-2 enhancer contains a functional motif named CD28 response element ( CD28RE ) that serves a role as a target for mitogenic T cell activation signals .
 CD28, IL-2, CD28 response element, CD28RE
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:
 CD28, IL-2, CD28 response element, CD28RE