Fig. 4: Infection, immunity, and protection of LAV-IV vaccine.
A Course of viremia in 8 RHV-rn1 infected naïve rats. B Experimental outline and timeline of vaccination and challenge study. C Course of viremia after R3-UpAhigh prime and booster vaccination and RHV-rn1 challenge infection in 12 male (blue) and 12 female (pink) rats. In vivo rescued R3-UpAhigh virus was used for vaccination. Rat-726 (male) developed persistent viremia of the R3-UpA virus, shown as a blue circle and red connecting lines. D Comparison of R3-UpA viremia after prime dose in male (n = 9) and female (n = 10) rats at day 7 pi. Two-tailed unpaired t-test between Male and Female group, p-value = (**, 0.0024). Data points are presented as individual values and error bars at mean ± SD. E Comparison of virus-specific T cell frequencies targeting different viral proteins before and after 14 days of RHV-rn1 challenge in 4 vaccinated rats. The frequencies of IFN-γ secreting T cells, shown as SFU, in ELISPOT assay in LILs stimulated with a pool of peptides representing the RHV-rn1 T cell epitopes. The mean value of SFU counts in triplicate wells is shown. Two-tailed paired t-test- before and after challenge for each peptide pool. P-values for E1 (**, 0.006), E2 (*, 0.0106), NS5B (*, 0.036) and Epitope-Pool (***, 0.0001). F Viremia on day 7 after RHV-rn1 challenge in rats that subsequently cleared the infection (n = 18) or remained chronic (n = 5). Two-tailed unpaired t-test; p-value (**, 0.0066). Data points are presented as individual values and error bars at mean ± SD. G Frequencies of virus-specific IFN-γ + T cells in PBMC of rats, before and after RHV-rn1 challenge, showing their significant expansion after challenge, on 9 dpi. Rat 473 and 474 developed chronic RHV-rn1 infection. H Frequencies of CD8 T cells producing IFN-γ after antigen stimulation in the liver of cleared (blue font) and chronic (red font) rats after 100 dpi. I Surface expression of various CD8 T cell markers shown as Fluorescence minus one (FMO) control (grey) and rat MHC class I Tetramer+ CD8 T cells in the liver of cleared (shades of blue) and chronic (shades of red) rats. J Sequence alignments of RHV-rn1 and R3-UpA genomes recovered from rats that developed chronic infection. The parallel grey lines show nucleotide (upper) and amino acid (lower) mutations (black marks) compared to the RHV-rn-1 genome. Alignment was generated using a consensus sequence derived from >200 X coverage of each nucleotide position, and the recognized base was present in >75% of sequence reads. The sequences are submitted to GenBank (PV639513-PV639519). Source data are provided as a Source Data file.
