Biology subjects

Segovia, K.

Publications and source records attributed to Segovia, K..

3 recordsLinked to original sources

bioRxiv2024

Genetic insertion of mouse Myxovirus-resistance gene 1 increases innate resistance against both high and low pathogenic avian influenza virus by significantly decreasing replication in chicken DF1 cell line

Avian influenza virus (AIV) is a constant threat to animal health with recent global outbreaks resulting in the death of hundreds of millions of birds with spillover into mammals. Myxovirus-resistance (Mx) proteins are key mediators of the antiviral response that block virus replication. Mouse (Mu) Mx (Mx1) is a strong antiviral protein that interacts with the viral nucleoprotein to inhibit polymerase function. The ability of avian Mx1 to inhibit AIV is unclear. In these studies, Mu Mx1 was stably introduced into chicken DF1 cells to enhance the immune response against AIV. Following infection, titers of AIV were significantly decreased in cells expressing Mu Mx1. In addition, considerably less cytopathic effect (CPE) and matrix protein staining was observed in gene-edited cells expressing Mu Mx1, suggesting Mu Mx1 is broadly effective against multiple AIV subtypes. This work provides foundational studies for use of gene-editing to enhance innate disease resistance against AIV.

immunology↗

bioRxiv2024

Morphologic characterization and cytokine response of chicken bone-marrow derived dendritic cells to infection with high and low pathogenic avian influenza virus

Dendritic cells (DCs) are professional antigen-presenting cells, which are key components of the immune system and involved in the early immune response. DCs are specialized in capturing, processing, and presenting antigens to facilitate immune interactions. Chickens infected with avian influenza virus (AIV) demonstrate a wide range of clinical symptoms, based on pathogenicity of the virus. Low pathogenic avian influenza (LPAI) viruses typically induce mild clinical signs, whereas high pathogenic avian influenza (HPAI) induce more severe disease, which can lead to death within days. For this study, chicken bone marrow-derived DC (ckBM-DC)s were produced and infected with high and low pathogenic avian influenza viruses of H5N2 or H7N3 subtypes to characterize innate immune responses, study effect on cell morphology, and evaluate virus replication. A strong proinflammatory response, including chicken interleukin-1{beta}, and stimulation of the interferon response pathway were observed at 8 hours post infection. Microscopically, the DCs underwent morphological changes from classic elongated dendrites to a more general rounded shape that eventually lead to cell death with the presence of scattered cellular debris. Differences in onset of morphologic changes were observed between H5 and H7 subtypes. Increases in viral titers demonstrated that both HPAI and LPAI are capable of infecting and replicating in DCs. The elevated expression of infected DCs may be indicative with a dysregulation of the immune response typically seen with HPAI infections.

immunology↗

bioRxiv2023

Novel technology to develop non-transmissible live influenza virus vaccines through alterations in M2/M42 ion channel expression

Continued global outbreaks of H5Nx highly pathogenic avian influenza viruses (HPAIV) have been reported in poultry since the emergence of the Asian Goose/Guangdong lineage of HPAIV H5N1 in 1996. Consequently, vaccines have been developed and employed to protect commercial and non-commercial poultry flocks. However, constant changes in virus immunogenetics makes vaccine candidates that prevent morbidity, mortality, reduce shedding, and prevent transmission a moving target. Here, we tested the effects of disrupting the mRNA splice sites and thus expression of either of the two isoforms of the viral ion channel M2 and M42 expressed by the H5N2 low pathogenic avian influenza virus (LPAIV) progenitor of the 1983 Pennsylvania HPAIV outbreak. Both G52C ({Delta}M2) and G145A ({Delta}M42) versions of the A/chicken/Pennsylvania/1/83 (Ck/Penn) virus replicated well in vitro and in ovo, but showed altered virion morphology, with the G145A virus exhibiting filamentous budding. The G52C and G145A viruses also infected chickens efficiently and stimulated robust immune responses; however, unlike the wild type virus, they did not transmit to naive-contact birds. In protection studies, vaccination of birds with G52C or G145A viruses protected 100% of birds from lethal challenge with homologous and distant heterologous H5 HPAIV strains from North American and Asian lineages and significantly reduced virus shedding compared to controls. Furthermore, the live virus vaccines decreased virus shedding 10,000-fold more than corresponding inactivated forms of the vaccine virus. Taken together, these studies demonstrate a strategy for developing a non-transmittable but highly protective live attenuated virus for AIV.

microbiology↗