FIG 1.

Construction and characterization of the recombinant RABV expressing IL-7 or IL-7(-) in vitro. (A) Schematic diagram describing the construction of rLBNSE, rLBNSE-IL-7(-), and rLBNSE-IL-7. The pLBNSE plasmid was derived from the SAD-B19 vaccine strain by deleting the long, noncoding region of the G gene and adding BsiWI and NheI sites between the G and L genes. Murine IL-7 was inserted into the RABV genome between the G and L genes instead of into the deleted long noncoding region. rLBNSE-IL-7(-) was constructed by the substitution of STOP codons for the START codons within IL-7 gene. (B and C) Multiple-step growth curves for rRABVs on BSR cells (B) and NA cells (C) at a multiplicity of infection (MOI) of 0.01 are shown. (D) The expression level of murine IL-7 was determined by ELISA. Briefly, BSR cells were infected with rLBNSE or rLBNSE-IL-7(-) or rLBNSE-IL-7 (MOI = 1, 0.1, 0.01, or 0.001) for 24 h, and the cell culture supernatants were then harvested to determine the quantity of murine IL-7 by using a commercial ELISA kit. (E) BSR cell viability of rLBNSE-IL-7 was similar to that of rLBNSE-IL-7(-) and rLBNSE. Error bars represent the standard deviations (SD; n = 3), and data are representative of results of two independent experiments. OD, optical density.