Identification and selective expansion of functionally superior T cells expressing chimeric antigen receptors

Background: T cells expressing chimeric antigen receptors (CARs) have shown exciting promise in cancer therapy, particularly in the treatment of B-cell malignancies. However, optimization of CAR-T cell production remains a trial-and-error exercise due to a lack of phenotypic benchmarks that are clearly predictive of anti-tumor functionality. A close examination of the dynamic changes experienced by CAR-T cells upon stimulation can improve understanding of CAR–T-cell biology and identify potential points for optimization in the production of highly functional T cells. Methods: Primary human T cells expressing a second-generation, anti-CD19 CAR were systematically examined for changes in phenotypic and functional responses to antigen exposure over time. Multi-color flow cytometry was performed to quantify dynamic changes in CAR-T cell viability, proliferation, as well as expression of various activation and exhaustion markers in response to varied antigen stimulation conditions. Results: Stimulated CAR-T cells consistently bifurcate into two distinct subpopulations, only one of which (CARhi/CD25+) exhibit anti-tumor functions. The use of central memory T cells as the starting population and the resilience—but not antigen density—of antigen-presenting cells used to expand CAR-T cells were identified as critical parameters that augment the production of functionally superior T cells. We further demonstrate that the CARhi/CD25+ subpopulation upregulates PD-1 but is resistant to PD-L1-induced dysfunction. Conclusions: CAR-T cells expanded ex vivo for adoptive T-cell therapy undergo dynamic phenotypic changes during the expansion process and result in two distinct populations with dramatically different functional capacities. Significant and sustained CD25 and CAR expression upregulation is predictive of robust anti-tumor functionality in antigen-stimulated T cells, despite their correlation with persistent PD-1 upregulation. The functionally superior subpopulation can be selectively augmented by careful calibration of antigen stimulation and the enrichment of central memory T-cell type. Electronic supplementary material The online version of this article (doi:10.1186/s12967-015-0519-8) contains supplementary material, which is available to authorized users

Nutritional, structural and chemical defenses of common algae species against juvenile sea urchins

Este artículo contiene 14 páginas, 6 figuras, 3 tablas.Herbivory is a widespread biotic interaction with important ecological and evolutionary implications. Benthic marine systems show greater producer consumption than any other aquatic or terrestrial environment. Marine algae and plants have a variety of defensive mechanisms such as structural, chemical, and nutritional traits with the capacity to reduce herbivore consumption. These mechanisms can function simultaneously. Here, we quantified consumption by juvenile Diadema africanum and Paracentrotus lividus on 15 algal species (1) to investigate the relative contribution of algal nutritional, chemical, and structural traits to the patterns of consumption and (2) to assess whether this relative contribution varies as a function of herbivore species. Differences in consumption were found between sea urchins; however, changes differed across algal and herbivore species.There was no clear relationship between the nutritional contents and consumption rates on the studied species of algae. The structure and chemical defenses of algae species played an important role in the feeding behavior of the studied herbivores. Our results suggest that multiple defensive traits may be necessary to deter herbivores in the field.This study was funded by the ‘Fundación Caja Canarias’ under postgraduate fellowship (awarded to Adriana Rodríguez). This research is a contribution of the Consolidated Research Group "Grupo de Ecología Bentónica" (SGR2009-655) of the Catalan Government.Peer reviewe