5847
In conclusion, we show that CD3 ligation by mAb and SE triggers a rapid, PP1 -sensitive tyrosine and serine phosphorylation of Stat3 in human CD4+ T cells .
 PP1, CD3, T cells, mAb, human CD4+ T cells, Stat3
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:
 PP1, CD3, T cells, mAb, human CD4+ T cells, Stat3