TABLE 1.

Quantification of the different types of particles within factories of cells infected with the indicated viruses^a

Virus	% (mean ± SEM) of particles
	Empty	Immature	Defective	Mature
BA71V	0.08 ± 0.09	52.39 ± 3.16	2.61 ± 0.57	45.14 ± 3.09
v62i
With IPTG	1.33 ± 0.89	51.78 ± 3.48	3.18 ± 1.00	43.51 ± 3.86
Without IPTG	18.23 ± 1.03	64.85 ± 1.78	16.62 ± 1.14	0.64 ± 0.15

^aThin sections of COS cells infected with BA71V or with v62i, maintained for 24 h in the presence or absence of IPTG, and fixed at 24 hpi were examined under the electron microscope. For each factory the percentages of empty, immature, defective, and mature particles were estimated. More than 1,000 particles were counted for each virus and condition in at least 25 different factories.