Cytopathic effect of heat-labile toxin of Bordetella parapertussis on aortic smooth muscle cells from pigs or guinea pigs

The in vitro effect of the heat-labile toxin (HLT) of Bordetella parapertussis on HeLa, baby hamster kidney (BHK), chinese hamster ovary (CHO), myeloma (Pa-NS-1), human embryonic lung (HEL-R66) cells, erythrocytes, adipocytes and lymphocytes from guinea pigs, mice or rats, or aortic smooth muscle cells from pigs or guinea pigs was examined. Within 8, 6, 4, 2, and 2 hr after the exposure to 1, 3, 10, 30, and 100 MNDs/ml of HLT, respectively, the cultured smooth muscle cells only showed a cytopathic change. When the cells exposed to HLT were washed out within 60 min post-exposure, the change could be induced with an extend period of lag. Histamine, KCl or norepinephrine caused similar change in the cells, but the period of lag was within 30 min. The HLT activity was neutralized by an anti-B. parapertussis- or B. bronchiseptica-HLT guinea pig IgG. HLT had no effects on any other cells tested.