design: In order to keep the conditions of air exposure unchanged, the hard clams were put into a multi-thermo incubator  with temperature and humidity set at 15  and 60%, respectively. After exposure for 20 days, 18 live clams were randomly sampled and Hemolymphs from six clams were pooled into one sample and three were three replicates. The hemolymph was filtered through a 70 m cell strainer to eliminate debris and haemocytes were obtained by centrifugation of whole hemolymph at 800 g, 4 for 8 min.