873
In conclusion, HIV-1 and HIV-2 are differentially regulated by T cell activation signals, and this difference may account for the longer period of viral latency observed with HIV-2 than with HIV-1 infection .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
Answer:
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