Label‐free live cell imaging by Confocal Raman Microscopy identifies CHO host and producer cell lines

Abstract

As a possible viable and non‐invasive method to identify high producing cells, Confocal Raman Microscopy was shown to be able to differentiate CHO host cell lines and derivative production clones. Cluster analysis of spectra and their derivatives was able to differentiate between different producer cell lines and a host, and also distinguished between an intracellular region of high lipid and protein content that in structure resembles the Endoplasmic Reticulum. This ability to identify the ER may be a major contributor to the identification of high producers. PCA enabled the discrimination even of host cell lines and their subclones with inherently higher production capacity. The method is thus a promising option that may contribute to early, non‐invasive identification of high potential candidates during cell line development and possibly could also be used for proof of identity of established production clones.

Raman microspectroscopy for the development and screening of recombinant cell lines

“…Based on the average Raman spectra from single cells and multivariate analysis, the authors showed that producing cells could be distinguished from their non-producing host cells, enabling Raman microspectroscopy as a label-free tool to identify protein-producing cells from a heterogeneous cell pool after transfection [1]. The authors identified several Raman bands that differed between the high-producer and non-producer cells.…”

“…An ideal technological platform for recombinant cell line development would allow for the label-free identification of protein expression levels based on very small cell numbers or even at the single cell level, at an early stage of the cell cloning procedure. As reported by Prats Mateu et al, Raman microspectroscopy is a potential technique that could address these needs [1]. In their study, single cells were scanned using Raman microspectroscopy and two established recombinant CHO cell lines, one producing the monoclonal antibody adalimumab and a second one producing human diamine oxidase, were investigated.…”

“…As demonstrated by Prats Mateu et al in this issue of Biotechnology Journal, Raman microspectroscopy has great potential to detect multiple cellular features, which are specific for high-producer cells [1]. The technology could therefore potentially replace traditional laborious single cell cloning techniques in the near future.…”

“…However, in biopharmaceutical industry there is a growing need to establish novel cost effective and simple methods that facilitate the selection procedure of high-producer cell clones [6]. In this issue, Prats Mateu et al employed Raman microspectrocopy on recombinant high-producer CHO cells and compared the spectral information of these cells with different non-producing host CHO cell lines [1]. The authors demonstrated that Raman spectroscopy is capable to discriminate producing and nonproducing CHO cells based on their biochemical fingerprints, which were detected from living single cells without the use of external labels.…”

“…Combined with multivariate analyses tools, Raman microspectroscopy enables the label-free characterization and imaging of single cells based on spatially resolved biochemical information. In this issue of Biotechnology Journal, Prats-Mateu et al report on the use of Raman microspectroscopy for the imaging of living recombinant chinese hamster ovary (CHO) cells [1]. The authors showed that Raman microspectroscopy allowed the discrimination of high-producer cells from their non-producing host cells.…”