Biology subjects

Donofrio, G.

Publications and source records attributed to Donofrio, G..

4 recordsLinked to original sources

bioRxiv2023

Vaccination of cattle with a virus-vectored vaccine against a major membrane protein of Mycobacterium a. subsp. paratuberculosis elicits CD8 cytotoxic T cells that kill intracellular bacteria

Infection of cattle with Mycobacterium a. subsp. Paratuberculosis (Map), the causative agent of paratuberculosis, induces an immune response directed toward a 35 kD major membrane protein (MMP) of Map. CD8 cytotoxic T cells (CTL) are elicited when peripheral blood mononuclear cells from healthy cattle are incubated ex vivo with antigen-presenting cells (APC) primed with bacterial recombinant MMP. Ex vivo development of CTL was MHC-restricted and required the presence of both CD4 and CD8 T cells. The gene MAP2121c, encoding MMP, was modified to express a modified form of MMP (p35NN) in a mammalian cell line, also capable of eliciting an ex vivo CTL response. In the present study, the modified gene for p35NN was placed into a BoHV4 vector to determine the potential use of BoHV-4A{Delta}TK-p35NN as a peptide-based vaccine. Subcutaneous vaccination of healthy cattle with BoHV-4A{Delta}TK-p35NN elicited a CTL recall response, as detected ex vivo. Further studies are warranted to conduct a challenge study to determine if CD8 CTL elicited by vaccination with BoHV-4A{Delta}TK-p35NN prevents the establishment of a persistent infection by Map.

immunology↗

bioRxiv2023

Metagenomic analysis of milk microbiota in the bovine subclinical mastitis

Subclinical mastitis is one of the most widespread diseases affecting dairy herds with detrimental effects on animal health as well as on milk productivity and quality. Despite the multi-factorial nature of this intramammary infection, the presence of pathogenic bacteria is regarded one of the main drivers of subclinical mastitis, leading to a disruption of the homeostasis of the bovine milk microbial community. However, the bovine milk microbiota alterations associated with subclinical mastitis still represents a largely unexplored research area. In this context, the species-level milk microbiota of a total of 75 milk samples, collected from both healthy and subclinical mastitis-affected cows from two different stables, was deeply profiled through an ITS, rather than a traditional, and less informative, 16S rRNA gene microbial profiling-based sequencing. Surprisingly, the obtained data of the present pilot study, not only revealed that subclinical mastitis is characterized by a reduced number of species in the bovine milk microbiota, but also that this disease does not induce standard alterations of the milk microbial community across stables. In addition, a flow cytometry-based total bacterial cell enumeration highlighted that subclinical mastitis is accompanied by a significant increment in the number of milk microbial cells. Furthermore, the combination of the metagenomic approach and total bacterial cell enumeration allowed to identify different potential microbial marker strictly correlated with subclinical mastitis across stables.

microbiology↗

bioRxiv2022

Characterization of BoHV-4 ORF45

Bovine herpesvirus 4 (BoHV-4) is a Gammaherpesvirus of the genus Rhadinovirus, his natural host is the bovine whereas the African Buffalo the natural reservoir. Anyhow, BoHV-4 infection is not associated to a specific disease. Genome structure and genes are well conserved in Gammaherpesvirus, and orf45 gene and its product, ORF45, is one of those. BoHV-4 ORF45 has been suggested to be a tegument protein, however, BoHV-4 ORF45 structure and function have not yet been experimentally characterized. In the present study, it is shown that BoHV-4 ORF45, despite its poor homology with other characterized Rhadinovirus ORF45s, is structurally related to Kaposis sarcoma-associated herpesvirus (KSHV), is a phosphoprotein and localizes in the host cell nuclei. Through the generation of an ORF45-null mutant BoHV-4 and its pararevertant, it was possible to demonstrate that ORF45 is essential for BoHV-4 lytic replication and is associated to the viral particles, as for the other characterized Rhadinovirus ORF45s. Finally, the impact of BoHV-4 ORF45 on cellular transcriptome was investigated, an aspect poorly explored or not at all for other Gammaherpesvirus. Many cellular transcriptional pathways were found to be alterate, mainly those involving p90 ribosomal S6 kinase (RSK) and signal-regulated kinase (ERK) complex (RSK/ERK), thus highlighting the authentic character of BoHV-4 ORF45 and paving the way to further investigations.

microbiology↗

bioRxiv2022

Natural heteroclitic-like peptides are generated by SARS-CoV-2 mutations

Mutations carried by SARS-CoV-2 spike protein variants may promote viral escape from immune protection. Humoral immunity is sensitive to evasion by SARS-CoV-2 mutants, but the impact of viral evolution on the interplay between virus and host CD8 T cell reactivity remains uncertain. By a systematic functional analysis of 30 spike variant mutations, we show that in vaccinated as well as convalescent subjects, mutated epitopes can have not only a neutral or abrogating effect on the recognition by CD8 T cells but can also enhance or even generate de novo CD8 T cell responses. Large pools of peptides spanning the entire spike sequence and comprising previously identified CD8 T cell epitopes were then used in parallel with variant peptides to define strength and multispecificity of total anti-spike CD8 responses. In some individuals, CD8 cells were narrowly focused on a few epitopes indicating that in this context of weak and oligospecific responses the overall antiviral protection can likely benefit of the function enhancing effect of heteroclitic-like mutations. In conclusion, appearance of mutated stimulatory epitopes likely reflects an epiphenomenon of SARS-CoV-2 evolution driven by antibody evasion and increased transmissibility, that might bear clinical relevance in a subset of individuals with weak and oligospecific CD8 T cell responses.

immunology↗