Development of a Cell Culture Method for Quantal Assay of Strain I-2 of Newcastle Disease Virus

Abstract

Repeated titrations of strains of Newcastle disease virus (NDV) are more conveniently undertaken in cell cultures rather than in embryonated eggs. This is relatively easy with mesogenic and velogenic strains that are cytopathic to various cell lines, but is difficult with avirulent Australian isolates that are poorly cytopathic. Strain V4 for example has been shown to be pathogenic iin vitro only to of chicken embryo liver cells. Strain I-2 was reported to produce cytopathic effect (CPE) on chicken embryo kidney (CEK) cells. The present studies confirmed this observation and developed a quantal assay. CEK cells infected with strain I-2 developed CPE characterized by degeneration, rounding, granularity and vacuolation, and the formation of synctia. End points were readily established by microscopic examination of fixed and stained cells. In virus infectivity studies on strain I-2, where multiple titrations are required and where large numbers of samples are used, titration using CEK cell grown in microtitre plates is recommended. Such studies may not be feasible in embryonated eggs.

Infection of Bone Marrow-Derived Mesenchymal Stem Cells with Virulent Newcastle Disease Virus Maximizes Cytokine Production: A Step Toward vNDV Immunotherapy

“…Log phase cells were used to adapt vNDV by passaging on cell culture. vNDV was titrated on CEF as described by Wambura et al (2006), and the titer was calculated according to Reed & Muench, (1938).…”