242750
Specific effects on cells In the macrophage , the primary signal for activation is IFN-γ from Th1 type CD4 T cell s. The secondary signal is CD40L ( CD154 ) on the T cell which binds CD40 on the macrophage cell surface .
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Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
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