7653
However, examination of proteasome activity in these T cells using fluorogenic peptide assays revealed a significant age-related decline in chymotryptic activity .
 T cells, proteasome
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:
 T cells, proteasome