Progress in the development of a cell culture system to study the immune responses of reef-building corals

• Published in: The Journal of immunology (1950) 2018-05, Vol.200 (1_Supplement), p.59-59.1
• Main Authors: Garrison, Keith E., Kuo, Catherine
• Format: Article
• Language: English
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.200.Supp.59.1

Previous work in the laboratory has focused on using fragments of aquaculture-raised specimens of the stony coral Acropora and Montipora. We are interested in these species because Acropora has an expanded immune gene repertoire in comparison to the closely-related anemone species Nematostella, especially in the number of TLR and IL-1R genes. However, space restrictions and maintaining acceptable water chemistry parameters pose a challenge to working with samples of stony corals in this form. In addition, coral fragments are complex holobionts that contain a mixture of coral cells, photosynthetic zooxanthelle, and bacteria, all on a calcium carbonate skeletal matrix. We seek a simplified model system of coral cells growing in isolation to facilitate performing the virus isolation, propagation, and controlled infection experiments that we think are necessary to advance our understanding of coral disease and immune responses. A number of protocols exist to propagate coral cells in a mixture of artificial seawater and typical mammalian cell growth medium. We compared the results of mechanical versus enzymatic isolation of coral tissues from the underlying skeletal matrix. We performed microscopic assessments of the coral and endosymbiont cells immediately following isolation and again after one week in culture. The endosymbiont zooxanthelle are easily visually distinguishable, and appear to persist longer under our culture conditions than the coral cells. It is unclear whether this is due to an improved ability of the zooxanthelle to live independently, or increased susceptibility of the coral cells to pathogen infections not eliminated by antibiotics in the culture medium.