ABSTRACT
AIMS: In previous studies, the present group showed that a factor, present in the cerebrospinal fluid of seven neuro-patients, was capable of inducing cell damages on cell cultures of epithelial cells (Vero), glial cells (DG54-MG) and human primary lymphocytes. The cytotoxicity, once induced, could be transmitted to fresh cell cultures using crude preparations obtained from the cytotoxic cell cultures. METHODS AND RESULTS: The present electron microscope study describes in detail the pathological changes occurring in the previously assayed cultured cell types, and for the first time in human fibroblasts, as a consequence of the treatment with crude cytotoxic preparation. It also demonstrates with reasonable certainty the absence of virus-like particles in both the treated cells and the partially purified cytotoxic fraction. Indeed high-resolution electron microscopy analysis shows that this fraction consists almost entirely of protein spheroids with a diameter of 8-12 nm. CONCLUSIONS: The possible significance of nanotubular aggregates, observed in particular in the glial and in the epithelial cells undergoing cytotoxic damage, is also discussed.