TABLE 2.
Macrophage tropism and presence of N283 in HIV-1 R5 envelopesa
| Study group | Source | No. of patients | Fraction of macrophage- tropic envelopesd | Frequency of N283 in C2 CD4 binding site |
|---|---|---|---|---|
| Adult | Brain, proviral | 5 | 10/11 | 8/11 |
| Lymph node, proviral | 3 | 0/9 | 1/9 | |
| Blood, proviral | 3 | 0/6 | 0/6 | |
| Semen, proviral | 3 | 1/5 | 0/5 | |
| Pediatric | Plasma, RNA | 3 | 4/23 | 0/23 |
| Controls | Macrophage tropicb | 4/4 | 1/4 | |
| Non-macrophage tropicc | 0/1 | 0/1 |
a
N283 was present in the C2 CD4 binding site that lies just upstream of the V3 loop, for which the HXBc2 sequence is TDNAKTIIVQLNTSVEINCTRPNNNTRKRIRIQRGPGRAFVTIGKIGNMRQAHC. T283 is in bold, while residues that contact CD4 are underlined. The V3 loop is in italics.
b
Envelopes SF162, JRFL, AD8, and YU2.
c
Envelope JR-CSF.
d
Fraction of envelopes that conferred macrophage infectivity of >1% of that recorded for SF162.