Counting rare earth metals.

For this editorial, I planned an experiment to write an augmented intelligence editorial with the help of ChatGPT. This worked quite nicely and yielded well formulated text. After several cycles, I had a 10 lines compendium of one of the articles from this issue of Cytometry Part A. But in the end, it took much longer than writing by myself. So, I went back to the old fashioned hand written editorial. This month's Editor's Choice article is by Stevens and colleagues (In this Issue pp. 631–645). The original research work deals with the quantitation of the number of surface antigens on immune cells by mass cytometry. Molecule counting using fluorescent dye conjugated antibodies and flow cytometry has been established more than 20 years ago. However, to the best of my knowledge so far not done using metal conjugated monoclonal antibodies (mAB) And measurement by mass cytometry. In their work, the authors demonstrate for the first time the methodological approach for counting different CD-marker molecules on human peripheral blood leukocyte subsets by mAB conjugated to different isotopes of the Lanthanide series. They report of comparable molecule numbers obtained by mass cytometry and by traditional flow cytometry for CD4-molecule on T-Lymphocytes. Importantly, they show that the antibody numbers counted per cell are not independent of the metal isotopes conjugated to the mAB. Whereas for three metal isotopes similar molecule numbers were obtained that corresponded to the numbers from the flow cytometry data, two isotopes produced systematically higher or lower numbers. Overall, the results presented in this study demonstrate the immense potential of mass cytometry as a powerful tool for high-dimensional cellular analysis. These data can provide a solid rationale for further exploration and integration of this technology into various areas of biomedical research, drug discovery and cancer therapy follow up [1]. In a technical note Pink and colleagues (In this Issue pp. 670–683) demonstrate the pivotal importance of antibody titration and standardized preanalytical procedures, flow cytometric measurement and data analysis in the analysis of extracellular vesicles (EV) by microflow cytometry. The authors demonstrate that standardized protocols play a crucial role in defining the optimal antibody concentration. Using such protocols will ensure consistency and comparability of results across different experiments and laboratories. This approach will ultimately improve the overall quality of the data generated. Finally, the OMIP-69 record of maximal number of colors of measured by spectral flow cytometry from 2020 [2] was broken by Brandi and colleagues (In this Issue pp. 624–630) by one more color added. In their OMIP-93 the authors are presenting a 41-color OMIP for murine lymphoid and myeloid cells in order to measure different co-inhibitory molecules. Congratulations for this achievement! I hope for your interest in the briefly reported excellent research papers as well as the those published in this August 2023 issue of Cytometry Part A.