6884
HIV-1 reactivation in resting peripheral blood mononuclear cells of infected adults upon in vitro CD4 cross-linking by ligands of the CDR2-loop in extracellular domain 1 .
 CDR2-loop, resting peripheral blood mononuclear cells, CD4, extracellular domain 1
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:
 CDR2-loop, resting peripheral blood mononuclear cells, CD4, extracellular domain 1