Direct activation of the J774.1 Murine macrophage cell line by mycoplasma arthritidis.

Viable Mycoplasma arthritidis and supernatants from M. arthriditis cultures produced marked morphological changes in the J774.1 continuous macrophage line similar to those seen during activation of these cells by Mycobacterium bovis BCG cell walls. The mycoplasma-treated macrophages developed pronounced tumoricidal activity against syngenic 3T12-3 target cells and developed an enhanced capacity for the killing of intracellular listeriae, including both virulent and laboratory-maintained strains. Increased acid phosphatase levels and [14C]glucosamine uptake were also seen. We conclude that mycoplasmas can profoundly alter the functions of macrophages, an event which may not only have in vivo significance with regard to disease pathogenesis, but which may pose considerable problems for in vitro work when unsuspected mycoplasma contamination is present.