Myoclonus is a characteristic neurological sign of subacute sclerosing panencephalitis (SSPE). Attempts were made to induce myoclonus in a large proportion of hamsters with a cell-associated strain of SSPE virus (the Biken strain) and thereby to establish an experimental model for study of the mechanism of development of this condition. When injected intracerebrally, Biken virus induced myoclonus within two to 14 days in 84% of the three- to nine-week-old hamsters tested. Electroencephalographic traces showed a periodic and synchronous discharge consisting of high-voltage slow waves and spikes that appeared coincidentally with myoclonus. Neurons in the cortex and thalamus of the affected animals had severely degenerated cytoplasm. Inflammatory changes, such as perivascular cuffing or infiltration of mononuclear cells, were not detected. Staining with immunoperoxidase revealed measles viral antigens in the cytoplasm and dendrites of the affected neurons. SSPE virus with the same properties as the parent virus was recovered from brain cells of sick animals by cocultivation with Vero cells.

SUMMARYThe expression of Forssman-type heterophile antigen on Marek's disease (MD) virus (MDV)-transformed cell lines, MDCC-MSB 1, -HP 1, -RP 1 and -BP 1, and avian leukosis virus (ALV)-transformed cell lines, LSCC-1104B1 and -1104X5 was investigated by membrane immunofluorescence and complement-dependent antibody cytotoxicity tests. Forssman antigen was detected on a high percentage of the cells in two ALV-transformed cell lines and on a smaller percentage of splenic lymphocytes from normal chicken. Of the MDV-transformed cell lines tested only the RP1 and BP1 cell lines, derived from transplantable MD tumours, expressed Forssman antigen, while the MSB 1 and HP 1 cell lines, derived from MD lymphomas, did not. Forssman antigen appears to be unrelated to MD tumour-associated surface antigen (MATSA).

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