How can new technologies help to solve old problems? A study with the echinoderm immune system.
Echinoderms (sea stars and sea urchins) are exclusively marine invertebrates, which similarly to vertebrates, use their circulating cells (i.e. coelomocytes) as their first line of immune defense. However, the lack of an effective method to isolate these different coelomocytes is one of the main problems for understanding the immune responses of these organisms. In this work, carried out during an abroad internship (BEPE-FAPESP), and in collaboration with the University of Palermo (Italy), we use image flow cytometry (IFC) – which allows us to individually photograph each cell passing through the sensor – to investigate the coelomocytes of the sea urchins Arbacia lixula and Lythechinus variegatus. Using this method, it was possible to determine specific parameters to identify four cell populations: large and small phagocytes, red spherulocytes, and vibratile cells. Additionally, it was also evaluated whether the approach could be used to monitor the dynamics of the coelomocytes of Arbacia lixula during one experimental bacterial infection. Our results showed in detail the coelomocytes dynamics during an immune response. Of particular interest, we can cite the decrease in the frequency of vibratile cells in the face of bacterial infection, which unequivocally indicates for the first time that this population has an immune function in these organisms. Lastly, considering the frequency of all cell types analyzed during bacterial infection, it was possible to provide a model that describes how these cells cooperate during an immune response. Thus, considering that (1) echinoderm coelomocytes have traditionally been identified based on their shape, and (2) IFC can analyze conventional parameters along with cell morphology, this method has great potential as a tool to characterize coelomic cells and study the physiology of echinoderms.
Do you want to know more about the results? Check out the full article at: https://doi.org/10.1016/j.fsi.2020.12.014
Queiroz, V., Muxel, S. M., Inguglia, L., Chiaramonte, M., & Custódio, M. R. (2021). Comparative study of coelomocytes from Arbacia lixula and Lythechinus variegatus: cell characterization and in vivo evidence of the physiological function of vibratile cells. Fish & Shellfish Immunology, 110, 1-9.