Biology subjects

Cabral, C.

Publications and source records attributed to Cabral, C..

2 recordsLinked to original sources

bioRxiv2022

The ATLAS™ screening assay reveals distinct CD4+ and CD8+ SARS-CoV-2 antigen response profiles which have implications to Omicron cellular immunity

The emergence of SARS-CoV-2 variants are a persistent threat to the efficacy of currently developed prophylactic vaccines and therapeutic antibodies. These variants accumulate mutations in the spike protein which encodes the epitopes necessary for neutralizing antibody binding. Moreover, emerging evidence suggest that robust antibody responses are insufficient to prevent severe disease and long-lasting viral immunity requires T cells. Thus, understanding how the T cell antigen landscape evolves in the context of these emerging variants remains crucial. T cells responses are durable and recognize a wider breadth of epitopes reducing the possibility of immune escape through mutation. Here, we deploy the ATLAS assay which identifies CD4+ and CD8+ T cell antigens by utilizing the endogenous HLA class-I and class-II peptide processing pathways. Profiling of T cells from exposed and unexposed donors revealed rich and complex patterns which highlighted the breadth of antigenic potential encoded in SARS-CoV-2. ATLAS revealed several common or frequent antigenic regions as well as an abundance of responses in the unexposed cohort potentially the result of pre-exposure to related coronaviruses. ORF10 was a common CD4+ response in the unexposed cohort while spike was identified as a common and frequent target in both cohorts. Moreover, the spike response profiles allowed us to accurately predict the impact of Omicron spike mutations. This analysis could thus be applied to study the impact of future emerging VOCs.

immunology↗

bioRxiv2021

Effects of a blend of chestnut and quebracho tannins on gut health and performance of broiler chickens

Consumer demands and increased regulations on the use of antimicrobials in farm animals accentuated the need to develop strategies to replace antimicrobial growth promoters (AGPs) in food-producing animals. The present study evaluates the productive and gut health outcomes during the implementation of AGPs free programs based on the inclusion of a tannin blend compared with AGPs based program under commercial conditions. In the first trial, 6 farms were randomly assigned to AGP or tannin-based programs. In a second trial, both programs were applied simultaneously in one farm and the results were studied over 1 year. Although productive results from both trials were similar among treatments, evaluations of gut health indicators show improvements in the tannins treated flocks. Frequency and severity of intestinal gross lesions were reduced in jejunum (42% vs 23%; p<0.05 - 1.37 vs. 0.73; p<0.01, respectively) and ileum (25% vs. 10%; p<0.0.5 - 1.05 vs. 0.58; p<0.01) in tannins treated birds. Results from 16S studies, show that cecal microbiota diversity was not differentially affected by AGPs or tannins, but changes in the relative abundance of certain taxa were described, including Lactobacillus and Bifidobacterium groups. Additional evaluations using an in vivo model for C. perfringens necrotic enteritis showed that tannins treated birds had reduced incidence of gross lesions in jejunum (43.75 vs. 74.19%; p<0.01) and ileum (18.75% vs. 45.16%; p<0.05) compared with control. These results suggest that AGPs can be replaced by tannins feed additives, and contribute in the implementation of antimicrobial-free programs in broilers without affecting health or performance.

microbiology↗