Cloning and codon optimization of a novel feline interferon omega gene for production by Pichia pastoris and its antiviral efficacy in polyethylene glycol-modified form

Identification of prevalent Feline Calicivirus strains and novel antiviral efficacy of CpG49 stimulus in Feline Calicivirus-infected cats

Feline calicivirus (FCV) is a highly mutable and prevalent virus causing significant suffering in cats and currently lacking effective cures, while FCV studies mainly focus on prevention. To obtain an active therapeutic against FCV, we established a reliable FCV infection model using the prevalent FCV strain (FG24-1) isolated from clinical samples and evaluated the therapeutic effect of TLR9 agonist CpG49 (a CpG plasmid with well-immunostimulatory capacity) on this model. Our results showed that CpG49 elicited strong Th1-biased interferon (I and II) responses, thereby significantly inhibiting FCV replication both in vitro and in vivo. Notably, CpG49 significantly reduced serum levels of the inflammatory marker fSAA (maximum reduction: 40.38 %) while upregulating IFN-γ (maximum increase: 2.14-fold), suggesting its potential to alleviate excessive inflammatory damage and provoke a more balanced immunity. These immunostimulatory effects of CpG49 lessened clinical symptoms, accelerated recovery (high-dose CpG49 group showed 3-day shorter oral inflammation recovery time, 2-day less fever duration, and faster weight recovery), and reduced viral shedding (53.4 % lower on day 6 and 97.4 % lower on day 9 after treatment) in FCV-infected cats. This study supports CpG49's potential as a promising and safe therapeutic agent against FCV, providing a new direction for developing cost-effective FCV therapeutics.

Blocking virus infection with BacMam virus delivery bovine interferon-α gene

Interferon-αs (IFN-αs) are crucial cytokines for inducing protective antiviral responses. The baculovirus-mediated gene transduction of mammalian cells (BacMam) is an efficient delivery tool for recombinant protein expression in mammalian cells. This study focuses on the delivery of bovine IFN-α (BoIFNα) using the BacMam system. A recombinant pACEMam1-BoIFNα bacmid was constructed, and a recombinant BacMam-BoIFNα virus was obtained. After transducing HEK293T cells with this virus, BoIFNα protein was successfully secreted into the cell supernatant, displaying antiviral activities against VSV, BPIV3, BEV, and BVDV in bovine-derived cells. Additionally, the BacMam-BoIFNα virus inhibited the replication of these viruses in MDBK cells, induced the transcription of ISGs, and the expression of M × 1 in both MDBK and BT cells. These induction effects were significantly reduced following treatment with a JAK1 inhibitor, suggesting that the BacMam-BoIFNα virus exerts antiviral activity in MDBK cells through JAK-STAT signaling pathway. Furthermore, the study found that the BacMam-BoIFNα virus significantly inhibited the replication of BPIV3 in the lung and trachea of mice. Overall, this study demonstrates that the BacMam-BoIFNα virus have antivirus activities both in vitro and in vivo, signaling through JAK-STAT pathway, and provides an efficient interferon gene delivery tool for combating bovine viral infections.

Molecular Characterization of Feline Parvovirus from Domestic Cats in Henan Province, China from 2020 to 2022

Carnivore protoparvovirus-1, feline parvovirus (FPV), and canine parvovirus (CPV) continue to spread in companion animals all over the world. As a result, FPV and CPV underwent host-to-host transfer in carnivorous wild-animal hosts. Here, a total of 82 fecal samples of suspected cat FPV infections were collected from Henan Province from 2020 to 2022. The previously published full-length sequence primers of VP2 and NS1 genes were used to amplify the targeted genes of these samples, and the complete gene sequences of 11 VP2 and 21 NS1 samples were obtained and analyzed. Analysis showed that the amino acid homology of the VP2 and NS1 genes of these isolates was 96.1-100% and 97.6-100%, respectively. The phylogenetic results showed that the VP2 and NS1 genes of the local isolates were mainly concentrated in the G1 subgroup, while the vaccine strains were distributed in the G3 subgroup. Finally, F81 cells were inoculated with the local endemic isolate Luoyang-01 (FPV-LY strain for short) for virus amplification, purification, and titer determination, and the pathogenesis of FPV-LY was detected. After five generations of blind transmission in F81 cells, cells infected with FPV-LY displayed characteristic morphological changes, including a round, threadlike, and wrinkled appearance, indicative of viral infection. The virus titer associated with this cytopathic effect (CPE) was measured at 1.5 × 106 TCID50/mL. Subsequent animal regression tests confirmed that the virus titer of the PFV-LY isolate remained at 1.5 × 106 TCID50/mL, indicating its highly pathogenic nature. Cats exposed to the virus exhibited typical clinical symptoms and pathological changes, ultimately succumbing to the infection. These results suggest that the gene mutation rate of FPV is increasing, resulting in a complex pattern of gene evolution in terms of host preference, geographical selection, and novel genetic variants. The data also indicate that continuous molecular epidemiological surveillance is required to understand the genetic diversity of FPV isolates.

Chromosome-level genome provides insights into environmental adaptability and innate immunity in the common dolphin (delphinus delphis)

The common dolphin (Delphinus delphis) is widely distributed worldwide and well adapted to various habitats. Animal genomes store clues about their pasts, and can reveal the genes underlying their evolutionary success. Here, we report the first high-quality chromosome-level genome of D. delphis. The assembled genome size was 2.56 Gb with a contig N50 of 63.85 Mb. Phylogenetically, D. delphis was close to Tursiops truncatus and T. aduncus. The genome of D. delphis exhibited 428 expanded and 1,885 contracted gene families, and 120 genes were identified as positively selected. The expansion of the HSP70 gene family suggested that D. delphis has a powerful system for buffering stress, which might be associated with its broad adaptability, longevity, and detoxification capacity. The expanded IFN-α and IFN-ω gene families, as well as the positively selected genes encoding tripartite motif-containing protein 25, peptidyl-prolyl cis-trans isomerase NIMA-interacting 1, and p38 MAP kinase, were all involved in pathways for antiviral, anti-inflammatory, and antineoplastic mechanisms. The genome data also revealed dramatic fluctuations in the effective population size during the Pleistocene. Overall, the high-quality genome assembly and annotation represent significant molecular resources for ecological and evolutionary studies of Delphinus and help support their sustainable treatment and conservation.