7863
On first encounter with antigen, naive CD4+ T helper (Th) cells differentiate into cytokine -producing effector cells .
 naive CD4+ T helper (Th) cells, cytokine, cytokine -producing effector cells
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:
 naive CD4+ T helper (Th) cells, cytokine, cytokine -producing effector cells