Comparative assessment of β-propiolactone, binary ethyleneimine and formaldehyde in inactivating Foot and Mouth Disease virus serotype O
Muhammad Amjad Iqbal1, 2, Noreen Sarwar1*, Sohail Raza1, Sehrish Firyal3, Rabia Riaz4, Afia Muhammad Akram5, Rashad Munir4, Aamir Riaz Khan4, Mobeen Sarwar6, Muhammad Imran Arshad7
1Institute of Microbiology, University of Veterinary and Animal Sciences, Lahore, Pakistan
2Veterinary Research Institute, Lahore, Pakistan
3Institute of Biochemistry and Biotechnology, University of Veterinary and Animal Sciences, Lahore, Pakistan
4Foot and Mouth Disease Research Centre, Lahore, Pakistan
5Department of Zoology, Division of Science and Technology, University of Education, Lahore, Pakistan
6Livestock and Dairy Development, Government of Punjab, Lahore, Pakistan
7Institute of Microbiology, University of Agriculture, Faisalabad, Pakistan
Abstract
Inactivation of foot-and-mouth disease virus (FMDV) with Formalin (FA) and binary ethyleneimine (BEI) is a slow process and takes long time. The purpose of this study was to evaluate β-Propiolactone (BPL), an alkylating agent that is frequently used in vaccine development and production, as a candidate for the inactivation of FMDV serotype O. Virus was grown on confluent monolayer of BHK-21 cell line. Harvesting was performed between 18 and 20 hours after infection, when CPE was between 90 and 95%. The virus was subjected to inactivation with formalin (0.02%), BEI (2mM, 2.5mM, 3mM) and BPL (0.1%, 0.2 and 0.4%) at 4°C and 37°C. Samples (05 mL/each) were collected after 0, 2, 4, 8, 16, and 24 hours post treatment. The biological titer (TCID50/ml) of each inactivated sample was measured. An innocuity test was used to further confirm the inactivation. RT-PCR was used to detect viral genome damage by amplification of VP1 gene. Data were analyzed by one-way analysis of variance and pair wise comparison was made by post hoc Tukey’s HSD test. Linear regression was used in Microsoft Excel Version 2010. The virus titers after 0.02% formalin treatment were 7.172±0.298 and 4.584±1.362 at 4°C and 37°C respectively. The virus titers were 6.036±0.513, 5.622±0.298, and 5.150±0.449 with 2mM, 2.5mM, 3mM BEI at 4°C and 1.646±1.0210, 1.050±0.644, 0.492±0.492 at 37°C respectively. Inactivation with 0.1%, 0.2% and 0.4% BPL at 4°C resulted in virus titers of 2.386±1.1104, 1.4400±0.9445 and 0.6960±0.6960 respectively. Rapid inactivation of virus with all three BPL concentrations at 37°C gave mean titer of 0.00±0.00. There was a significant difference (P<0.05) among all treatment groups with highest inactivation rates recorded for BPL.
