Fig. 9
ADCC killing T. spiralis NBL. a-f Morphology of T. spiralis NBL recovered after ADCC test with different cultivation time periods. The NBL were cultured using anti-rTsSPI serum and 1 × 105 mouse peritoneal exudate cells (PECs) at 37 °C for different time periods. a, b No PECs were adhered to NBL 12 h and 24 h of cultivation and the NBL was wriggling. c A few of PECs adhering to NBL 48 h of cultivation and the NBL was limp with weak activity. d A dead NBL overlaid with PECs 72 h of cultivation. Infection serum (e) and pre-immune serum (f) were utilized as control sera. g-h ADCC killing T. spiralis NBL is anti-rTsSPI antibody dose-dependent and associated with culture time. g The NBL were incubated with same dilution (1:100) of various sera for 12–72 h of incubation; the cytotoxicity had an increasing trend with the culture time prolongation. h The NBL were incubated with different sera diluted at 1:50 to 1:800 for 72 h; the cytotoxicity exhibited an anti-rTsSPI antibody dose-dependent pattern. Asterisks indicate that the cytotoxicity of the anti-rTsSPI serum exhibited a significant difference (P = 0.005) compared with that of the pre-immune serum