1978 Volume 52 Issue 7 Pages 240-245
From the metacercariae of Stellantchasums falcatus encytsed in fish, Rickettsia sennetsu-like organisms (SF strain) were occasionally isolated. These organisms were difficult to detect in stamped specimens of lymph nodes or spleens of infected mice by the Macchiavello staining or the indirect immunofluorescence. Therefore, cultivation of SF strain in RK-13 cell and its antigenic relation to Rickettsia sennetsu were studied. The results were as follows.
1. Cultivation of SF strain in RK-13 cell 0.5 ml of supernatant fluid from 10% homogenate of spleens of mice infected with SF strain was added to the monolayer culture of RK-13 cell in 50 ml bottle and incubated at 37°C. At the interval of about 12 days, the cells collected by trypsinization and centrifugation were subcultured in two bottles. The organisms were observed in a few cells of the 3rd transfered cells, and in 90% cells of the 5th. After 90% cells were infected, normal RK-13 cells must be added at the time of subculture.2. Common antigen between SF strain and Rickettsia sennetsuCommon antigen between SF strain in RK-13 cell and Rickettsia sennetsu in FL cell was studied by indirect immunofluorescence. The anti-SF strain mouse serum, homologous titer of 1: 2560, stained Rickettsia sennetsu at the dillution of 1: 160, and the three Hyuga-fever patients' sera, homologous titers of 1: 1280, 1: 1280 and 1: 160, had titers of 1: 160, 1: 160 and 1: 40 respectively against SF strain. From these results, speculatively, there is not a close relationship between SF strain and Rickettsia sennetsu.
