The effect of polyclonal antibody on intracellular calcium increase induced by Mycoplasma hyopneumoniae in porcine tracheal cells

An investigation was undertaken to assess whether polyclonal convalescent and hyperimmune sera obtained from pigs inhibit Mycoplasma hyopneumoniae induced increases in intracellular calcium [Ca²⁺]_i in ciliated porcine tracheal cells. Basal [Ca²⁺]_i in the tracheal cells was 97 ± 13 nM (n = 22 cells in four experiments) and after exposure to M. hyopneumoniae (300 μg/mL or 10¹¹ CCU/mL), [Ca²⁺]_i increased by 246 ± 56 nM within 100 s. After pre-treatment with hyperimmune or convalescent serum, M. hyopneumoniae increased [Ca²⁺]_i by 196 ± 43 and 223 ± 65 nM, respectively. It was found that neither hyperimmune nor convalescent serum significantly prevented the increase in [Ca²⁺]_i compared with M. hyopneumoniae alone. It was concluded that polyclonal antibodies produced by mycoplasma vaccination or exposure to the pathogen do not prevent M. hyopneumoniae-induced increase in [Ca²⁺]_i.