5749
Moreover T cell proliferation was unaffected by the addition of blocking Abs to both IL-2 and the IL-2 receptor , demonstrating that this form of costimulation by CD28 was independent of IL-2 .
 IL-2, IL-2, IL-2 receptor, CD28, IL-2, Abs
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:
 IL-2, IL-2, IL-2 receptor, CD28, IL-2, Abs