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Human herpesvirus 6 ( HHV-6 ) is a lymphotropic herpesvirus , and in vitro, it can productively infect human CD4+ T cells as HIV-1 .
 CD4+ T cells
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:
 CD4+ T cells