Biology subjects

Costantini, D.

Publications and source records attributed to Costantini, D..

4 recordsLinked to original sources

bioRxiv2024

Lower baseline immunity in invasive Egyptian goose compared to sympatric native waterfowls

Successful invasive species increase their spreading success by trading-off nutritional and metabolic resources allocated to reproduction and range expansion with other costly body functions. One proposed mechanism for the reallocation of resources is a trade-off with the immune function and the regulation of oxidative status. Relying on a panel of blood-based markers of immune function and oxidative status quantified in an invasive species (Egyptian goose) and two native competing species (mallard and mute swan) in Germany, we tested the hypothesis that the invasive species would have (i) lower investment in immune function, (ii) lower levels of oxidative damage, and (iii) no higher antioxidant defences compared to the native species. We found lower levels of adaptive immune markers (lymphocytes and immunoglobulin Y), in the invasive species compared to the two native species. Reactive oxygen metabolites, a marker of oxidative damage, were also lower in Egyptian geese compared to the other species, while levels of antioxidants were generally similar. Mute swans showed the highest levels of heterophils, lysozymes and haemolysis among the three species, possibly due to its larger body mass. Our results point to a reduced investment in adaptive immune function in the invasive species as a possible resources-saving immunological strategy due to the loss of co-evolved parasites in the new colonised habitats, as observed in a previous study. A lower investment in immune function may benefit other energy-demanding activities, such as reproduction, dispersal, and territoriality. Research highlightsOur results point to a reduced investment in adaptive immune function in invasive Egyptian geese compared to native and sympatric waterfowl species, as a possible resources-saving immunological strategy due to the loss of co-evolved parasites in the new colonised habitats.

ecology↗

bioRxiv2022

Spatial differentiation of background matching strategies along a Late Pleistocene range expansion route

Late Pleistocene climate changes have deeply impacted the range dynamics of temperate species. While the genetic legacy of these dynamics has been widely investigated, little is known about their phenotypic consequences. Anti-predatory strategies offer intriguing opportunities to study phenotypic evolution in response to dispersal dynamics since the ability to avoid predation can be pivotal for populations colonizing new environments. Here we investigated the spatial differentiation of background colour matching strategies along a Late Pleistocene range expansion route of a temperate species, the Tyrrhenian tree frog Hyla sarda. Using common-garden experiments, we investigated whether individuals sampled in the source area (Sardinia) and individuals sampled in the newly founded area (Corsica) differ in two components of the camouflage strategy: colour change abilities and background choice behaviour. We found a remarkable spatial structure in both colour change abilities and background choice behaviour, across the expansion range. Tree frogs from the source area displayed higher colour change abilities and a more pronounced preference for a greener background, with respect to tree frogs from the newly colonized area. We discuss these results in the context of the spatial and demographic components of the expansion dynamics. Our results support the intriguing hypothesis that Late Pleistocene biogeographic history might be an overlooked major player in shaping current spatial patterns of phenotypic traits variation across animal populations.

evolutionary biology↗

bioRxiv2022

Evolution of personality and locomotory performance traits during a late Pleistocene island colonization in a treefrog

Recent empirical and theoretical studies suggest that personality and locomotory performance traits are crucial components of the dispersal syndromes, and that they can evolve during a dispersal process. Island colonisation is one the best characterized processes in dispersal biogeography, and its implication in the evolution of phenotypic traits has been investigated over a wide range of temporal scales. However, the effect of island colonization on personality and performance traits of natural populations has been little explored, and no studies have addressed these processes in the context of late-Pleistocene range expansions. Here, we investigated the contribution of island colonisations triggered by post-glacial range expansions to intraspecific variation in personality and locomotory performance traits. We compared boldness, exploration, jumping performance, and stickiness abilities, in three equidistant populations of the Tyrrhenian tree frog Hyla sarda, two from the source area and one from the colonised island. Individuals from the colonised population were significantly bolder than individuals from the source area, as they emerged sooner from a shelter (p=0.028), while individuals from the source area showed markedly higher jumping and stickiness performance (both p<0.001). We discuss these results in the context of the major microevolutionary processes at play during range expansion, including selection, spatial sorting, and founder effects. However, irrespective of the processes contributing the most, our results clearly indicate that late Pleistocene climatic changes have had major consequences not just on species range dynamics, but also on the spatial patterns of phenotypic variation within species, including personality and locomotory traits variation.

evolutionary biology↗

bioRxiv2020

Tissue-resident memory CD8 T-cell responses elicited by a single injection of a multi-target COVID-19 vaccine

The COVID-19 pandemic is caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) which enters the body principally through the nasal and larynx mucosa and progress to the lungs through the respiratory tract. SARS-CoV-2 replicates efficiently in respiratory epithelial cells motivating the development of alternative and rapidly scalable vaccine inducing mucosal protective and long-lasting immunity. We have previously developed an immunologically optimized multi-neoepitopes-based peptide vaccine platform which has already demonstrated tolerance and efficacy in hundreds of lung cancer patients. Here, we present a multi-target CD8 T cell peptide COVID-19 vaccine design targeting several structural (S, M, N) and non-structural (NSPs) SARS-CoV-2 proteins with selected epitopes in conserved regions of the SARS-CoV-2 genome. We observed that a single subcutaneous injection of a serie of epitopes induces a robust immunogenicity in-vivo as measured by IFN{gamma} ELIspot. Upon tetramer characterization we found that this serie of epitopes induces a strong proportion of virus-specific CD8 T cells expressing CD103, CD44, CXCR3 and CD49a, the specific phenotype of tissue-resident memory T lymphocytes (Trm). Finally, we observed broad cellular responses, as characterized by IFN{gamma} production, upon restimulation with structural and non-structural protein-derived epitopes using blood T cells isolated from convalescent asymptomatic, moderate and severe COVID-19 patients. These data provide insights for further development of a second generation of COVID-19 vaccine focused on inducing lasting Th1-biased memory CD8 T cell sentinels protection using immunodominant epitopes naturally observed after SARS-CoV-2 infection resolution. Statement of SignificanceHumoral and cellular adaptive immunity are different and complementary immune defenses engaged by the body to clear viral infection. While neutralizing antibodies have the capacity to block virus binding to its entry receptor expressed on human cells, memory T lymphocytes have the capacity to eliminate infected cells and are required for viral clearance. However, viruses evolve quickly, and their antigens are prone to mutations to avoid recognition by the antibodies (phenomenon named antigenic drift). This limitation of the antibody-mediated immunity could be addressed by the T-cell mediated immunity, which is able to recognize conserved viral peptides from any viral proteins presented by virus-infected cells. Thus, by targeting several proteins and conserved regions on the genome of a virus, T-cell epitope-based vaccines are less subjected to mutations and may work effectively on different strains of the virus. We designed a multi-target T cell-based vaccine containing epitope regions optimized for CD8+ T cell stimulation that would drive long-lasting cellular immunity with high specificity, avoiding undesired effects such as antibody-dependent enhancement (ADE) and antibody-induced macrophages hyperinflammation that could be observed in subjects with severe COVID-19. Our in-vivo results showed that a single injection of selected CD8 T cell epitopes induces memory viral-specific T-cell responses with a phenotype of tissue-resident memory T cells (Trm). Trm has attracted a growing interest for developing vaccination strategies since they act as immune sentinels in barrier tissue such as the respiratory tract and the lung. Because of their localization in tissues, they are able to immediately recognize infected cells and, because of their memory phenotypes, they rapidly respond to viral infection by orchestrating local protective immune responses to eliminate pathogens. Lastly, such multiepitope-based vaccination platform uses robust and well-validated synthetic peptide production technologies that can be rapidly manufactured in a distributed manner.

immunology↗