1810
Cell lines expressing single amino acid substitutions of the carboxyl - terminal asparagine of CD2 are incapable of avidity regulation by TCR signaling , PMA treatment , or elevation of intracellular cAMP levels , demonstrating that each of these stimuli utilizes a common structural element for regulating CD2 avidity .
 GENE: CD2; GENE: TCR; GENE: CD2
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: GENE 
Text: {0} 
Answer:
 GENE: CD2; GENE: TCR; GENE: CD2