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Mohapatra J.K.,Project Directorate on Foot and Mouth Disease ICAR | Pawar S.S.,Project Directorate on Foot and Mouth Disease ICAR | Tosh C.,Project Directorate on Foot and Mouth Disease ICAR | Subramaniam S.,Project Directorate on Foot and Mouth Disease ICAR | And 4 more authors.
Acta Virologica | Year: 2011

Extreme antigenic and genetic heterogeneity of serotype A foot-and-mouth disease virus (FMDV) population has resulted in change of vaccine strains in India twice in the last decade. In such a situation, complete characterization of the vaccine strains is imperative. With regard to the frequent outbreaks of this disease, FMDV field strains are also of interest. Therefore three vaccine strains and two field strains of type A FMDV from India were completely sequenced and the obtained sequences were subjected to sequence and phylogenetic analyses. Based on the complete coding region, all the Indian strains clustered in the Asia topotype and exhibited a more than 11% nt divergence from the other Asian strains. The 5′-UTR of some Indian strains revealed block deletions of 43 and 86 nt corresponding to the pseudoknot region. Amino acids S44 in VP2 and F164 in VP1 were found to be the exclusive signatures for the Asia topotype. The vaccine strains differed at 65 aa positions in the capsid region, 13 of them antigenically critical. Variability at such positions is likely to affect the antigenic profile of these strains. Complete genome sequences of the vaccine strains presented here could serve as the reference for any comparative genomics in future.


Biswal J.K.,Project Directorate on Foot and Mouth Disease ICAR | Mohapatra J.K.,Project Directorate on Foot and Mouth Disease ICAR | Bisht P.,Project Directorate on Foot and Mouth Disease ICAR | Subramaniam S.,Project Directorate on Foot and Mouth Disease ICAR | And 2 more authors.
Biologicals | Year: 2015

Field outbreak strains of foot-and-mouth disease virus (FMDV) infect host cells through certain Arg-Gly-Asp (RGD) dependent integrin family of cellular receptors. In contrast, FMDV adapted in non-host cell cultures are reported to acquire the ability to infect cells via heparin sulphate (HS) or other unidentified cell surface molecules. It has been reported that during the serial passage of FMDV serotype A in BHK-21 cell culture, VP2 E131K (E2131K) substitution was fixed within the heparin sulphate binding site. The fixation of positively charged residue at position VP2 131 of serotype A is considered to associate with the ability to utilise alternative receptor. In this study, an infectious full-length cDNA clone for Indian FMDV vaccine strain A IND 40/2000 was constructed. Through site-directed mutagenesis on the cDNA clone, recombinant virus containing positive charged amino acid residue at position VP2 131 was rescued. The recombinant mutated virus was shown to have specific and strong affinity for HS and demonstrated an enhanced infectivity in BHK-21 cell line. The introduction of lysine residue at VP2 131 position that allows cell culture adaptation of FMDV serotype A could be exploited for the generation of vaccine seed stocks with improved growth properties in BHK-21 cell line. © 2014 The International Alliance for Biological Standardization.


PubMed | Project Directorate on Foot and Mouth Disease ICAR
Type: Evaluation Studies | Journal: Archives of virology | Year: 2014

Detection of antibodies to nonstructural proteins (NSP) of foot-and-mouth disease virus is the preferred diagnostic method to differentiate infected from vaccinated animals. In India, an endemic region practising preventive biannual vaccination, 3AB3 indirect ELISA (r3AB3 I-ELISA) has been employed as the primary screening test for serosurveillance. However, because of the variability observed in the immune response to the NSPs, the likelihood of detecting or confirming an infected animal is increased if an antibody profile against multiple NSPs is considered for diagnosis. In this study, all three copies of NSP 3B were expressed in a prokaryotic system to develop an indirect ELISA (r3B I-ELISA). At the decided cutoff of 40 percent positivity, the diagnostic sensitivity and specificity of the r3B I-ELISA were estimated to be 92.1% (95% CI: 89.0-94.5) and 98.1% (95% CI: 96.9-98.8), respectively, as compared to 97.04% and 95.04% for r3AB3 I-ELISA. Although r3B I-ELISA displayed lower sensitivity compared to the screening assay, which could possibly be attributed to additional relevant B-cell epitopes in the carboxy-terminal half of the 3A protein, the former achieved considerably higher specificity on repeatedly vaccinated animals. NSP antibodies could be detected from 10 to as late as 998 days postinfection in experimental calves. Substantial agreement in the test results (90.6%) was found between the two ELISAs. The r3B I-ELISA, when used in conjunction with the r3AB3 I-ELISA as an integrated system, can potentially augment the efficiency and confidence of detection of infected herds against the backdrop of intensive vaccination.

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