13415
Apoptosis was prevented when CD4 truncated at residue 402 was expressed; however, cells expressing mutated receptors that do not associate with p56(lck) (mutated at the dicysteine motif and truncated at residue 418 ) but which conserved proximal domains of the cytoplasmic tail underwent apoptosis like wild- type CD4 .
 wild- type CD4, CD4, cytoplasmic tail, dicysteine motif, p56(lck), CD4
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:
 wild- type CD4, CD4, cytoplasmic tail, dicysteine motif, p56(lck), CD4