TABLE 5.

Summary of macrophage syncytia induction by patient and control envelopes

Patient envelopes	Phenotypea	Cell-cell fusion in macrophagesb
NA118 LN27	R5R3	−
NA118 LN33	R5R3	−
NA118 B12	R5R3	−
NA420 LN40	R5R3	−
NA420 LN85	R5R3	−
NA420 B13	R5	−
NA420 B33	R5	+
NA420 B42	R5	−
NA20 B59	R5R3***	++
NA20 B76	R5R3	−
NA176 B72	R5R3	−
NA176 B93	R5R3	+++
NA353 B27	R5R3	+++
SF162	R5*	+
JRCSF	R5	−
JRFL	R5R3	+
AD8	R5R3*	+++
YU2	R5R3*	+

^aCoreceptor use of control envelopes (SF162, JRCSF, JRFL, AD8, and YU2) was taken from the HIV sequence database (http://www.hiv.lanl.gov/). *, use of additional coreceptors; ***, use of several additional coreceptors.

^bCell-cell fusion data are representative of at least three independent experiments. Cell-cell fusion in GHOST/CCR5 cells and primary macrophages was assessed by the extent of syncytium formation following overnight cocultivation with 293T cells transfected with env⁺ pSVIIIenv and env mutant pNL43. For GHOST/CCR5 cells, all envelopes showed extensive syncytium formation involving over 50% of plated cells. Syncytium formation for primary macrophages is represented as follows: −, no syncytia formed; +, 0 to 10 large syncytia observed per well of a 48-well culture dish; ++, 10 to 25 syncytia per well; +++, >25 syncytia per well.