The organ culture method described by Pinkel was modified to use fragments 4×3×3mm in size, a Millipore filter membrane, THWPO 1400, as the supporting screen, and an autologous rabbit kidney capsule as the covering. It was applied to the cultivation of rabbit lymph node tissue. More than 50% of the cultured fragments retained the architecture characteristic of the lymph node in their dorsal regions. Such well maintained area occupied 1/2-3/4 of the thickness of each fragment, where lymphoid follicles with germinal centers were observed up to 4 weeks of cultivation.
The cultured fragments supported the multiplication of the lapinized strain of rinderpest virus, which had been reported to be unable to grow in ordinary rabbit cell cultures. The rabbit minimum infective dose of the cultured fragment reached as high a level as 10⁴/ml and occasionally 10⁵/ml. Infective virus and specific antigen remained in cultured fragments over a period of cultivation ranging from 2 to 39 days.
The susceptibility of the cultured fragments to the lapinized strain of rinderpest virus was 1/60 to 1/200 of that of intact rabbits. Neither inclusion body nor syncytium was recognized in the infected cultured fragments examined so far.