12901
Progesterone acts distally to the initial steps of T cell receptor ( TCR )-mediated signal transduction , since it blocks sustained Ca2+ signals after thapsigargin stimulation , as well as oscillatory Ca2+ signals , but not the Ca2+ transient after TCR stimulation .
 TCR, TCR, T cell receptor
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:
 TCR, TCR, T cell receptor