3685
HIV-1 infection resulted in constitutive, low-level expression of type 1 interferon ( IFN ) at the mRNA level .
 IFN, type 1 interferon
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:
 IFN, type 1 interferon