The same TNF-mediated excitotoxic ability is retained by T lymphocytes sorted from splenocyte suspensions of EAE mice in the acute phase of the disease (homologous chimeric ex-vivo EAE model) (4), and cannot be observed when mouse brain slices are incubated with T cells taken from sera of healthy individuals, from MS patients in the remitting phase of the disease and from splenocytes of healthy mice (3, 4). The gene discussed is TNF; the disease is myeloid sarcoma.