Figure 1.

Construction and characterization of rRABV expressing IL-15 in vitro and in vivo. (A) Schematic diagram for construction of LBNSE and LBNS-IL15. The pLBNSE vector was constructed from SAD-B19 by deleting the long non-coding region of the G protein, and introduced BsiWI and Nhe I sites between the G and L genes. N, P, M, G and L represented RABV nucleoprotein, phosphoprotein, matrix, glycoprotein, and polymerase genes, respectively. Virus growth curves were determined on BSR (B) and NA (C) cells. Cells were infected with either LBNSE or LBNSE-IL15 at a multiplicity of infection (MOI) of 0.01, and the culture supernatants were harvested at 1, 2, 3, 4 and 5 dpi. The virus growth curves were drawn based on the viral titers measured at each time point. Data are presented as the mean ± SD (n = 3). (D) Expression of IL-15 was detected in infected BSR cells by ELISA. BSR cells were infected with either the LBNSE or LBNSE-IL15 virus at the MOI = 0.001, 0.01, 0.1, or 1, and the culture supernatants were harvested at 24 h post infection. IL-15 was measured by ELISA. Data are presented as the mean ± SD (n = 3). (E) Cell viability of BSR cells infected with different rRABVs. BSR cells were infected at MOI = 1 with LBNSE or LBNSE-IL15 or mock infected with DMEM, and the culture supernatants were harvested at the indicated time points for cell viability detection. Data are presented as the mean ± SD (n = 3). (F) Body weight change curves of mice after infection with different rRABVs. Six-week-old female ICR mice (n = 10) were infected by the IC route with 2 × 10⁶ FFU of DMEM, LBNSE or LBNSE-IL15, and the body weights were monitored daily for 2 weeks.