TABLE 2.

Summary of transitional intermediates identified in this study^a

Macaque	Variant	Time of emergence	CD4 T-cell countb	V3 loop sequence	Tropism
CA28	Δ22-25	9 wpi	585	CTRPNNNTRRSIHI..GPGRAFY....IIGDIRQAHC	Dual-R
	RRW	11 wpi	237	---------K----..RRW----ATGD----------	Dual-X
DG08	HI	13 wpi	314	---------K--R-HI-------ATGD----------	R5X4c

^awpi, weeks postinfection. For V3 sequence, dots indicate gaps and dashes stand for identity in sequences. Amino acid residues predicted to confer CXCR4 usage are in bold type.

^bCD4 T cell count (per μl blood) at time of tropism variant emergence.

^cVariants with HI insertions in the V3 loop had been previously shown to be dualtropic (see Table 1).