Assessment of the pathogenicity of cell-culture-adapted Newcastle disease virus strain Komarov

Abstract

Newcastle disease vaccines hitherto in vogue are produced from embryonated chicken eggs. Egg-adapted mesogenic vaccines possess several drawbacks such as paralysis and mortality in 2-week-old chicks and reduced egg production in the egg-laying flock. Owing to these possible drawbacks, we attempted to reduce the vaccine virulence for safe vaccination by adapting the virus in a chicken embryo fibroblast cell culture (CEFCC) system. Eighteen passages were carried out by CEFCC, and the pathogenicity was assessed on the basis of the mean death time, intracerebral pathogenicity index, and intravenous pathogenicity index, at equal passage intervals. Although the reduction in virulence demonstrated with increasing passage levels in CEFCC was encouraging, 20% of the 2-week-old birds showed paralytic symptoms with the virus vaccine from the 18th(final) passage. Thus, a tissue-culture-adapted vaccine would demand a few more passages by CEFCC in order to achieve a complete reduction in virulence for use as a safe and effective vaccine, especially among younger chicks. Moreover, it can be safely administered even to unprimed 8-week-old birds.

Synergy between hemagglutinin 2 (HA2) subunit of influenza fusogenic membrane glycoprotein and oncolytic Newcastle disease virus suppressed tumor growth and further enhanced by Immune checkpoint PD-1 blockade

“…Newcastle disease virus is an avian paramyxovirus, which has been shown to induce oncolytic activity against human tumors [10]. Despite its wild-type, cell culture-adapted strains of NDV such as LaSota can be used as a safe oncolytic virus with minimum virulence activity [11]. The major concern with the employment of oncolytic viruses is a limitation related to their spread through the tumor microenvironment [12].…”

Destructive dose determination of electron beam irradiation for pathogenic bacteria in water medium by 96 well plate assay

“…In the present study, 96-well-plate was selected owing to its uniform size and thickness with universal standard; more over it is less than 2.5 cm and available readily with sterile condition, generally used for the assessment of virus potency (Visnuvinayagam et al, 2015a). So, other variables (errors) such as size, shape and density are kept constant; and hence the effect of EBI on different concentration of bacterial culture can be estimated with accuracy.…”

Rapid Development of an Effective Newcastle Disease Virus Vaccine Candidate by Attenuation of a Genotype VII Velogenic Isolate Using a Simple Infectious Cloning System

“…Prominently, genotype VII NDVs have gradually emerged as the main prevalent strains worldwide, implying the urgent requirement for a more efficient vaccine against this virulent genotype. As the Commission of the European Communities (CEC, 1993) has recommended against the use of a vaccine strain with an ICPI value more than 0.4, only the lentogenic strains can possibly be used as a vaccine (21). Newer vaccines have been developed by using the herpesvirus vectored and the LaSota strain-based recombinant viruses through reverse genetics and recombination technologies (17)(18)(19)(20)(21)(22).…”