CCR7 and infection: To determine whether double infection occurs stochastically across all CD4+ T cell subsets or is favored in certain subsets compared to others, we compared the contribution of naïve (TN, CCR7 + CD45RO-), central memory (TCM, CCR7 + CD45RO+), and effector memory (TEM, CCR7-CD45RO+) subsets to singly (EGFP+ or mCherry+) and doubly-infected (EGFP + mCherry+) cells in 7 donors infected with 1:1 ratios of EGFP and mCherry reporter viruses.