12548
However, its activity becomes lower in the double-positive and a fraction of the CD4+ CD8int/- cell population , indicating that an additional enhancer, located in either the first or the third intron of the CD4 gene , is required for CD4 gene expression in this population.
 CD4 gene, CD4 gene, CD4+ CD8int/- cell population
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 gene, CD4 gene, CD4+ CD8int/- cell population