Transmissible gastroenteritis virus induces apoptosis in swine testicular cell lines but not in intestinal enterocytes

Evidence of apoptosis caused by infection with the Purdue strain of transmi ssible gastroenteritis virus (TGEV) was sought in vitro tin infected swine testicular [ST] cells) and in vivo tin the intestinal tissues of infected p iglets). The methods used were (1) DNA electrophoresis for detection of DNA fragmentation, and (2) terminal deoxynucleotidyl transferase-mediated deox yuridine triphosphate-fluorescein nick and labelling (TUNEL). DNA "ladderin g" was detected in TGEV-infected ST tells only. Numerous signs of apoptosis were detected in TGEV-infected ST cells by TUNEL assay, the positive (dark brown) staining reaction being: present in the majority of cell nuclei, wi thout background staining. No such staining tvas seen in TGEV-infected ente rocytes at various times after inoculation of piglets. Thus, it would appea r that apoptosis does not occur in the enterocytes of piglets infected with TGEV. (C) 2000 Harcourt Publishers Ltd.