Pretti, M. A. M. | bioRxiv Science

bioRxiv2023

A multi-tissue single-cell tumor microenvironment atlas reveals myeloid-derived cell states with significant impact on clinical outcome

Tumor-associated myeloid-derived cells (MDCs) significantly impact cancer prognosis and treatment response due to their remarkable plasticity and tumorigenic behaviors. We integrated single-cell RNA-Sequencing datasets from seven different cancers, resulting in a comprehensive collection of 29 MDC subpopulations in the tumor microenvironment (TME). Distinguishing resident-tissue from monocyte-derived macrophages, we discovered a resident-tissue-like subpopulation within monocyte-derived macrophages. Additionally, hypoxia-driven macrophages emerged as a prominent TME component. Deconvolution of these profiles revealed five subpopulations as independent prognostic markers across various cancer types. Validation in large cohorts confirmed the FOLR2-expressing macrophage association with poor clinical outcomes in ovarian and triple-negative breast cancer. Moreover, the marker TREM2, commonly used to define immunosuppressive tumor-associated macrophages, cannot solely predict cancer prognosis, as different polarization states of macrophages express this marker in a context-dependent manner. This comprehensive MDC atlas offers valuable insights and a foundation for novel analyses, advancing strategies for treating solid cancers.

cancer biology↗

bioRxiv2021

New SARS-CoV-2 lineages could evade CD8+ T-cells response

BackgroundMany SARS-CoV-2 variants of concern have emerged since the Covid-19 outburst, notably the lineages detected in the UK, South Africa, and Brazil. Their increased transmissibility and higher viral load put them in the spotlight. Much has been investigated on the ability of those new variants to evade antibody recognition. However, not enough attention has been given to pre-existing and induced SARS-CoV-2-specific CD8+ T cell responses during the natural course of infection by new lineages. MethodsIn this work, we investigated the SARS-CoV-2-specific CD8+ T cell epitopes from the main variants of concern and the potential of associated mutations to trigger or hinder CD8+ T-cells response. We also estimated the populations coverage of these different lineages, considering peptide binding predictions to class I HLA alleles from 29 countries to investigate differences in the fraction of individuals expected to respond to a given epitope set from new and previous lineages. ResultsWe observed a lower populational coverage for 20B/S.484K (P.2 lineage) in contrast to an increased coverage found for 20H/501Y.V2 (B.1.351 Lineage) and 20J/501Y.V3 (P.1 lineage) compared to a reference lineage. Moreover, mutations such as Spike N501Y and Nucleocapsid T205I were predicted to have an overall higher affinity through HLA-I than the reference sequence. ConclusionsIn summary, the data in this work provided evidence for the existence of potentially immunogenic and conserved epitopes across new SARS-CoV-2 variants, but also highlights the reduced populationals coverage for the Brazilian lineage P.2, suggesting its potential to evade from CD8+ T-cell responses. Our results also may guide efforts to characterize and validate relevant peptides to trigger CD8+ T-cell responses, and design new universal T-cell-inducing vaccine candidates that minimize detrimental effects of viral diversification and at the same time induce responses to a broad human population.

immunology↗