Abstract
To characterize putative immune cells in ctenophores, I have developed enhanced cell culture methods for the lobate ctenophore, Mnemiopsis leidyi, that can be utilized for the isolation, morphological assessment, and functional characterization of a range of specific cell types including phagocytic cell types. Adapting viability assays used in other cell culture systems has enabled the production of robust and highly reproducible live ctenophore cell suspensions. Optimization of cell staining techniques with Mnemiopsis cell cultures has enabled further characterization of ctenophore cell types via the use of downstream multiplexing applications, including flow cytometry. The combined use of vital dyes and histology techniques have revealed a subpopulation of Mnemiopsis cells that resemble bilaterian phagocytic cell types. Additionally, the introduction of fluorescently tagged foreign particles into in vitro cell cultures have revealed a subpopulation of Mnemiopsis cells that engage in phagocytosis. To further study and isolate phagocytic cell types, I also adapted techniques to distinguish and isolate live Mnemiopsis cells using flow cytometry and fluorescence activated cell sorting (FACS). Application of these methodologies with Mnemiopsis cells will continue to facilitate the exploration of cellular biology in this early diverging non-bilaterian species. Additionally, experiments further characterizing putative ctenophore immune cells will elucidate relationships between the evolution of innate immunity and the diversification of Metazoan cell types. I also investigated the distribution of membrane-bound C-type lectin-like domain architectures across Eukarya. This domain architecture study highlights the pan-eukaryotic distribution of evolutionarily ancient protein domains that play a role in metazoan innate immunity.