Immunological functions of blood cells in the scallop Chlamys farreri
ZHANG Wei-Zhu 1,3, WU Xin-Zhong 2**, LI Deng-Feng1,SUN Jing-Feng11. South China Sea Institute of Oceanology, the Chinese Academy of Sciences, Guangzhou 510301,China2. College of Animal Sciences, Zhejiang University, Hangzhou 310029,China3. Department of Chemistry and Biology, Chuzhou College, Chuzhou 390000, Anhui,China
The internal defence system of bivalves is mostly represented by circulating haemocytes of the haemolymph. Light, electron and scanning electron microscopic studies were conducted to characterize the haemocytes and several parameters associated with cellular immunity in the scallop Chlamys farreri. The hemocyte densities in healthy and diseased scallop haemolymph were assessed 3.03±0.11×107 cell/ml and 2.78±0.34×107 cell/ml, respectively. The healthy haemolymph was comprised of about 42.6% granulocytes and 57.4 hyalinocytes, and the diseased haemolymph showed 40.2% and 59.8%, respectively. Assays of APIZYM on enzymatic activities of 19 enzymes in haemolymph were performed and, of these, 13 and 10 enzymes were detected in serum and cells, respectively. The level of these enzymes were higher in healthy haemolymph than in diseased ones. The results of phagocytosis revealed that phagocytic abilities for E. coli and Rickettsia-like organisms (RLOs) were 25.4% and 21.7%, respectively. Both granulocytes and hyalinocytes showed phagocytic response to the two strains of bacteria, E. coli and RLOs when incubated in suspension. The phagocytic ability of granulocyte which was 30%-40% was significantly higher than that of hyalinocyte which was 4.8%-14%. The study of influence of environmental stress factors on phagocytosis activity revealed that the stress of pathogen infection and higher temperature could reduce the phagocytosis activity, and no significant influence of senility or age showed in this study.