Table 1. Cytotoxic activity of recombinant VACVs.

Cell line	CD50, PFU per cell
	VV-GMCSF-Lact	VV-GMCSF-dGF
MCF10A	>10	>10
MCF7	0,049**	0,085**
Selectivity index*	>200	>100

^*Selectivity index was calculated for each virus as the ratio of CD₅₀ values for normal and tumor cells.

^**The difference between groups was statistically significant at p<0.05.

Cytotoxic activity was determined by XTT assay.