Browsing by Author "Gíria, Marta"
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- Adaptive evolution of PB1 from influenza A(H1N1)pdm09 virus towards an enhanced fitnessPublication . Santos, Luís A.; Almeida, Filipe; Gíria, Marta; Trigueiro-Louro, João; Rebelo-de-Andrade, HelenaPB1 influenza virus retain traces of interspecies transmission and adaptation. Previous phylogenetic analyses highlighted mutations L298I, R386K and I517V in PB1 to have putatively ameliorated the A(H1N1)pdm09 adaptation to the human host. This study aimed to evaluate the reversal of these mutations and infer the role of these residues in the virus overall fitness and adaptation. We generate PB1-mutated viruses introducing I298L, K386R and V517I mutations in PB1 and evaluate their phenotypic impact on viral growth and on antigen yield. We observed a decrease in viral growth accompanied by a reduction in hemagglutination titer and neuraminidase activity, in comparison with wt. Our data indicate that the adaptive evolution occurred in the PB1 leads to an improved overall viral fitness; and such biologic advantaged has the potential to be applied to the optimization of influenza vaccine seed prototypes.
- Functional compatibility of PB1 and antigenic proteins as a determinant of viral fitness and adaptation in the A(H1N1)pdm09Publication . Gíria, Marta; Louro, João; Rebelo de Andrade, HelenaObjectives: To determine if the functional compatibility between PB1 and antigenic proteins is a molecular determinant of virus growth and antigen yield in PR8:A(H1N1)pdm09 reassortants; To evaluate the phenotypic expression of reverting mutations R386K, I517V and L298I, previously identified as putatively associated with an enhanced functional compatibility between PB1 and HA in the A(H1N1)pdm09
- Outbreak of acute respiratory infection among infants in Lisbon, Portugal, caused by human adenovirus serotype 3 and a new 7/3 recombinant strainPublication . Andrade, Helena Rebelo de; Pereira, Cristiana; Gíria, Marta; Prudêncio, Ema; Brito, Maria João; Calé, Etelvina; Taveira, NunoHuman adenoviruses (AdVs) typically cause mild illnesses in otherwise healthy hosts. We investigated a pediatric outbreak of acute respiratory infection with fatal outcomes that occurred in Lisbon, Portugal, in 2004. Biological specimens were collected from 83 children attending two nurseries, a kinesiotherapy clinic, and the household of a nanny. Adenovirus infection was confirmed in 48 children by PCR and virus isolation. Most (96%) isolates were classified as being of subspecies B1. Phylogenetic analysis of fiber and hexon gene sequences revealed that most infants were infected with AdV serotype 3 (AdV3) strains. Infants attending one nursery harbored a new recombinant strain containing an AdV serotype 7 hexon and serotype 3 fiber (AdV7/3). Both the AdV3 and the AdV7/3 strains caused fatal infections. Two different serotype 3 strains were circulating in Lisbon in 2004, and the new AdV7/3 recombinant type originated from only one of those strains. These results demonstrate that recombination leads to the emergence of new adenovirus strains with epidemic and lethal potential.
- Reverse genetics vaccine seeds for influenza: Proof of concept in the source of PB1 as a determinant factor in virus growth and antigen yieldPublication . Gíria, Marta; Santos, Luís; Louro, João; Rebelo de Andrade, HelenaGrowth deficits of reverse genetics vaccine seeds have compromised effective immunization. The impairment has been attributed to sub-optimal protein interactions. Some level of dependence may exist between PB1 and antigenic glycoproteins, however, further research is necessary to clarify the extent to which it can be used in favor of seed production. Our objective was to establish proof of concept on the phenotypic outcome of PB1 source in the PR8: A(H1N1)pdm09 reassortants. Reassortants were generated with the gene constellation of the classical 6:2 PR8: HA, NApdm09 seed prototype and the 5:3 reassortant PR8: HA, NA, PB1pdm09. Viral growth and antigen yield were evaluated 12-60h post-infection. The 5:3 reassortant presented statistically significant growth and antigen yield improvements when compared to the 6:2. We believe these findings to be of promising value to vaccine research towards an improvement of reverse genetic seeds, an overall more cost-effective vaccine manufacture and timely delivery.
- Unlocking COVID therapeutic targets: A structure-based rationale against SARS-CoV-2, SARS-CoV and MERS-CoV SpikePublication . Trigueiro-Louro, João; Correia, Vanessa; Figueiredo-Nunes, Inês; Gíria, Marta; Rebelo-de-Andrade, HelenaThere are no approved target therapeutics against SARS-CoV-2 or other beta-CoVs. The beta-CoV Spike protein is a promising target considering the critical role in viral infection and pathogenesis and its surface exposed features. We performed a structure-based strategy targeting highly conserved druggable regions resulting from a comprehensive large-scale sequence analysis and structural characterization of Spike domains across SARSr- and MERSr-CoVs. We have disclosed 28 main consensus druggable pockets within the Spike. The RBD and SD1 (S1 subunit); and the CR, HR1 and CH (S2 subunit) represent the most promising conserved druggable regions. Additionally, we have identified 181 new potential hot spot residues for the hSARSr-CoVs and 72 new hot spot residues for the SARSr- and MERSr-CoVs, which have not been described before in the literature. These sites/residues exhibit advantageous structural features for targeted molecular and pharmacological modulation. This study establishes the Spike as a promising anti-CoV target using an approach with a potential higher resilience to resistance development and directed to a broad spectrum of Beta-CoVs, including the new SARS-CoV-2 responsible for COVID-19. This research also provides a structure-based rationale for the design and discovery of chemical inhibitors, antibodies or other therapeutic modalities successfully targeting the Beta-CoV Spike protein.