. 1998 Dec;72(12):9955–9965. doi: 10.1128/jvi.72.12.9955-9965.1998

TABLE 3.

Characterization of chimeric envelope glycoproteins

Envelope^a	SU density on virions^b	Cell-cell fusion^c	Infectivity^d on cells:		Level of interference^e
Envelope^a	SU density on virions^b	Cell-cell fusion^c	XC	XC-A-ST	Level of interference^e
MO	++	+	8 × 10⁶	8 × 10⁶	1
A	++	−	6 × 10⁶	5.1 × 10⁴	118
PROMO	−	+	4 × 10¹	<1 × 10¹	NA
BDPROMO	++	+	2 × 10⁶	2 × 10⁶	1
PROCMO	+	−	2.2 × 10⁶	2.7 × 10⁵	8
PROCTMMO	++	−	2.3 × 10⁶	4.5 × 10⁴	50

Envelope constructs depicted in Fig. 1 and 7.

Expression levels of SU glycoproteins on virion pellets as assessed by Western blot analysis. The ++, +, and − symbols indicate no difference, 1- to 10-fold-less SU expression, and less than 10-fold SU expression, respectively, compared to that of parental envelopes, respectively.

Fusion assays were performed by cocultivation of cells expressing the indicated envelope construct with XC cells. The presence (+) and absence (−) of syncytia are indicated.

Average titers of three experiments are shown. The standard errors did not exceed 30% of the titer values. Infectivity was expressed as LacZ IU per milliliter of viral supernatant.

Interference levels were calculated according to the following equation: (titer on XC cells/titer on XC-A-ST cells) × (MO titer on XC-A-ST cells/MO titer on XC cells). NA, not applicable.