Single‐cell technologies are revolutionizing the approach to rare cells

Valentina Proserpio,Tapio Lönnberg

doi:10.1038/icb.2015.106

Abstract

In the last lustrum single-cell techniques such as single-cell quantitative PCR, RNA and DNA sequencing, and the state-of-the-art cytometry by time of flight (CyTOF) mass cytometer have allowed a detailed analysis of the sub-composition of different organs from the bone marrow hematopoietic compartment to the brain. These fine-grained analyses have highlighted the great heterogeneity within each cell compartment revealing previously unknown subpopulations of cells. In this review, we analyze how this fast technological evolution has improved our understanding of the biological processes with a particular focus on rare cells of the immune system.

Highlights

We consider a human being as a single being, unique and unrepeatable
CD4+ T cells with transgenic recombinant T-cell receptor (TCR) have been shown to differentiate to both Th1 and Tfh-type cells, with the frequencies influenced by the strength of TCR signalling.[33]
We have developed a computational strategy for reconstructing TCR sequences from genome-wide single-cell transcriptomics data (Stubbington et al.) and applied it to murine CD4+ T cells activated during a Salmonella typhimurium infection

Summary

INTRODUCTION

We consider a human being as a single being, unique and unrepeatable. in the last few years multiple single-cell technologies have revealed that we are unique and unrepeatable, but we might be composed of millions of millions of unique and unrepeatable cells.[1,2,3,4,5] Most of our scientific knowledge originates from population data where cells belonging to the same subtype are considered as a single unit, in which all the members that compose the class are, by definition, homogeneous and identical. The instrument that has allowed most of the study of rare cell is the flow cytometer, where up to 17 different phenotypic markers can be analyzed at the same time per cell.[10] The most sophisticated and recent machine, with a flow rate of up to 100 000 events per second, allows the detection of cells at frequencies as low as 0.0001% The combination of this technology with the parallel development of both new specific fluorophore-conjugated antibodies, which presently span the whole visible and part of the near-infrared spectrum, and better and faster analysis algorithms is key for the identification and isolation of rare cells. NEWLY IDENTIFIED RARE SUBPOPULATIONS IN THE IMMUNE SYSTEM Single-cell sequencing has shown that almost each cell is different to every other cell[23] and has identified previously unknown hidden subpopulation of cells within the populations under study

Illumina Sequencer Illumina Sequencer

HETEROGENEITY OF THE CELLS OF THE THYMIC MEDULLA

HAEMATOPOIETIC STEM CELLS

Findings

Cell type