SPECIFIC REQUIREMENT OF SERINE FOR GROWTH OF NEWCASTLE DISEASE VIRUS

Eagle's MEM, which is free of serine, was unable to support the growth of Newcastle disease virus (NDV) in a clonal subline (S3T) of HeLa S3 cells which requires serine for optimum growth. Full growth of poliovirus was, however, achieved in the same condition. Eagle's MEM supplemented with l-serine at an optimum concentration of 1 mM supported the full growth of NDV. Kinetic experiments revealed that except in the first 2 hours after infection continued presence of exogenous serine was essential for the multiplication of NDV. At any time after 2 hours, upon the addition of serine and after certain periods of time lag (which could be overcome by 8 hours after infection), the logarithmic increase of the NDV progeny occurred at the same rate. In the serine-free medium, the synthesis of viral RNA or some virus-specific antigen(s) was found to proceed in the NDV-infected cells, while neither hemagglutinin production nor hemadsorption was observed. The possible role of serine for the growth of NDV was discussed. © 1969.