5140
However, it remains unclear how this viral protein induces a persistent rather than transient NF-kappaB response .
 viral protein, NF-kappaB
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:
 viral protein, NF-kappaB