Taguchi M, Tsutsui S, Nakamura O
School of Marine Biosciences, Kitasato University, 252-0373, Kanagawa, Japan.
School of Marine Biosciences, Kitasato University, 252-0373, Kanagawa, Japan.
Fish Shellfish Immunol. 2016 Nov;58:203-209. doi: 10.1016/j.fsi.2016.06.060. Epub 2016 Sep 12.
Echinoderms have many types of coelomocytes, which have been known to form aggregates immediately after they are removed from the coelom. To assess the roles that each type of coelomocyte plays in aggregate formation, cellular components of coelomocyte aggregates of the Japanese sea cucumber, Apostichopus japonicus, were investigated. The coelomocytes were tentatively classified into 12 types based on May-Grunwald/Giemsa staining. After the coelom was incubated for 30 min or 6 h, the aggregates were disaggregated completely with 200 mM EDTA. Differential counts of the dissociated cells indicated that the largest component of the aggregates was amoebocytes (67.8%) and the second-largest component of the aggregates incubated 30 min was a type of basophilic granulocyte. In the 6h-incubated aggregates, the fraction of amoebocytes decreased to 59.0%, while that of lymphoid cells significantly increased, which suggests that lymphoid cells participate in late-stage aggregation. After 24-h incubation, only a portion of the aggregated cells could be disaggregated with EDTA. After 48 h, most of the cells could not be detached from the aggregates. Microscopy of frozen sections of the aggregates after 6-h incubation revealed that amoebocytes constructed a mesh-like structure to which other types of cells adhered. After 48 h, the borders of the cells and the intracellular granules were not recognizable. In time-lapse microscopy, the aggregates were observed to move on a glass slide, which suggests that aggregates can "crawl" on the intraluminal surface of the coelom toward, for example, injured regions in the body of the sea cucumber.
棘皮动物有多种类型的体腔细胞，已知这些细胞从体腔中取出后会立即形成聚集体。为了评估每种类型的体腔细胞在聚集体形成中所起的作用，对日本刺参（Apostichopus japonicus）体腔细胞聚集体的细胞成分进行了研究。根据May-Grunwald/Giemsa染色，体腔细胞初步分为12种类型。将体腔孵育30分钟或6小时后，用200 mM EDTA将聚集体完全解离。对解离细胞的差异计数表明，聚集体中最大的成分是变形细胞（67.8%），孵育30分钟的聚集体中第二大成分是一种嗜碱性粒细胞。在孵育6小时的聚集体中，变形细胞的比例降至59.0%，而淋巴细胞的比例显著增加，这表明淋巴细胞参与后期聚集。孵育24小时后，只有一部分聚集细胞可以用EDTA解离。48小时后大部分细胞无法从聚集体上分离。对孵育6小时的聚集体冰冻切片进行显微镜观察发现，变形细胞构建了一个网状结构，其他类型的细胞附着在该结构上。48小时后，细胞边界和细胞内颗粒无法辨认。在延时显微镜下，观察到聚集体在载玻片上移动，这表明聚集体可以在体腔的腔内表面“爬行”，例如朝向海参体内的受伤区域。
