Hemadsorption expressed by cloned H genes from subacute sclerosing panencephalitis (SSPE) viruses and their possible progenitor measles viruses isolated in Osaka, Japan

Most subacute sclerosing panencephalitis (SSPE) viruses, including our Osak a-1, -2, and -3 strains isolated in Osaka, have shown negative hemadsorptio n (HAD) by African green monkey red blood cells. This property has been tho ught to be characteristic of SSPE virus as compared to the positive reactio n of the standard Edmonston strain of measles virus (MV), However, this ass umption has become quite obscure because MV mutates frequently at the genet ic level during its multiplication and also because recent field strains is olated by lymphoblastoid cell lines have shown negative HAD. To investigate the above issue, the nucleotide sequences of the hemagglutinin (H) genes f rom SSPE virus Osaka-1, -2, or -3 strains were compared to those of various MV field strains isolated in Osaka by Vero cells. The H gene sequences of three SSPE strains were relatively conserved without such biased hypermutat ion as had been observed in the matrix (M) gene of three SSPE strains. Howe ver, this analysis of the H gene sequence of the SSPE viruses enabled us to deduce possible progenitor MVs, which are in agreement with the deduction from the M gene analysis we reported previously. The HAD of Vero cells tran sfected with the cloned H cDNAs from the SSPE strains and their progenitors suggested that negative HAD of the SSPE viruses has been maintained as one of original properties of the progenitor MVs rather than having been acqui red as an altered one during long-term persistent infection in the brains o f patients with SSPE.