Studies on bovine enteroviruses. II. Serial passages and growth curves in various cell cultures

Abstract

All six virus which had beern isolated from the feces of apparently healthy cattle weretested for properties after serial passages. Then growth curves were drawn for them, includingtwo prototype viruses, in cells of bovine kidney, chick embryo, HeLa, PS (cell line isolatedfrom swine kidney), and TC (cell line isolated from chick embryo).I) All strains proliferated xxziLh cytopathogenic effect irr cultures of bovine kidney andPS cells. They were divided ixnto txxzo groups in cultures of HeLa cells. One group, including the K62 and K90 strains, grew with cytopathogenic effect and the other groupshovved neitlner virus multiplication nor cytopathogenic effect in HeLa cells. The K62, K88, K90, and K130 strains exhibited virus growth in TC cells, where the K136 and K145strains did not proliferate.2) 1-Iernagglutinating activity was changed in the serial passages in the cells used withbovine enteroviruses. Fluids of tissue cultures of the K62 and K90 strains in HeLa cellsand the K130 strain in TC cells failed to produce hernaggltatinating activities with two orthree passages. The K136 strain in PS cells and the K145 strain irn chick embryo cells, however, produced hemagglutinating activities with two or three passages. The K130 strainproduced no clear-cut hemagglutination by successive passages in chick embryo cells. Theother strains failed to change the hemagglutinating activity with serial passages itn TC cells.The pltenornenon has been recognized not only with human enteroviruses but also withbovine enteroviruses. It has been manifested not only by the virus which passed in malignantcells but also by the viruses which passed in normal heteroTogous cells.3) The progeny of the viruses began to be produced in bovine kidney cells 6 to 8hours after infection. Thereafter infective titers increased frc>rn 18 to 24 hours and reachedthe highest values at 24 to 36 hours. Virus growth occurred in PS and HeLa cells withinthe same time as in bovine kidney cells and earlier than it? chiclc embryo cells, in whichthe highest L