ABSTRACT
Vaccination is the only pragmatic approach to control foot and mouth disease in India. Strict quality control measures are essential to supply potent vaccine to the field application, in addition to monitoring the performance of the vaccine in the field. During the process of monitoring, an outbreak of FMD in vaccinated animals caused by type "O" virus in Tanjavur district of Tamil Nadu and a type "O" virus from unvaccinated herd of Karnataka were studied. Field isolates and vaccine virus were sequenced and analyzed. Data indicated that the virus from the outbreak in vaccinated cattle was a variant which could escape neutralization by antibodies against vaccine virus.
Subject(s)
Aphthovirus/genetics , Cattle Diseases/etiology , Disease Outbreaks/veterinary , Foot-and-Mouth Disease/epidemiology , Foot-and-Mouth Disease/etiology , Viral Vaccines/adverse effects , Amino Acid Sequence , Animals , Aphthovirus/classification , Aphthovirus/isolation & purification , Base Sequence , Capsid/genetics , Capsid Proteins , Cattle , Cattle Diseases/epidemiology , Cattle Diseases/virology , Cell Line , Cricetinae , DNA, Viral , Foot-and-Mouth Disease/virology , India/epidemiology , Molecular Sequence Data , Phylogeny , Sequence Homology, Amino Acid , Sequence Homology, Nucleic Acid , Viral Vaccines/geneticsABSTRACT
Variations in foot and mouth disease virus are due to amino acid substitutions in the VP1, which is a major immunogen. Analysis of this hypervariable region is essential to know the antigenic structure of the serotype and is necessary to select a suitable vaccine strain. FMDV type A22 is one of the four prevailing virus types for which the vaccine is used regularly. To understand the antigenic structure of this type, carboxy- terminal region of VP1 from two field isolates and vaccine virus were sequenced and analysed. The results indicate that, Indian A22 has distinct antigenic structure.
Subject(s)
Antigens, Viral/genetics , Aphthovirus/genetics , Aphthovirus/immunology , Amino Acid Sequence , Animals , Aphthovirus/classification , Base Sequence , Capsid/genetics , Capsid/immunology , Capsid Proteins , Cattle , Cattle Diseases/virology , DNA, Viral/genetics , Foot-and-Mouth Disease/virology , Immunodominant Epitopes/genetics , Molecular Sequence Data , Sequence Homology, Amino AcidABSTRACT
We have used the methylotrophic yeast, Pichia pastoris, to express the open reading frame 3 (ORF3) of the hepatitis E virus (HEV). The ORF3 gene codes for a 123-amino-acid protein that contains highly immunodominant epitopes and is a potentially useful diagnostic and immunoprophylactic antigen. The expressed protein showed positive on immunoblots probed against antibodies raised in rabbit and infected human patient sera. In order to optimize the ORF3 protein expression, we have examined the regulated expression of this protein and characterized it. Unlike its expression in E. coli, the ORF3 protein was present in both the soluble and insoluble fractions of the cell lysate. The expressed protein is not glycosylated and does not undergo any major processing in the host strain.
Subject(s)
Hepatitis E virus/genetics , Pichia/genetics , Viral Proteins/genetics , Cloning, Molecular , Genetic VectorsABSTRACT
The antigenic variation in Foot and Mouth Disease Virus (FMDV) is very high. The effective strategy to control the Foot and Mouth Disease (FMD) in India which is a habitat of four serotypes O, A, C and Asia 1, is by regular vaccination, using the vaccine strain most suitable for the local situation. India is an endemic country with the disease being widely distributed. Selection of vaccine strain should therefore need the information on the circulating viruses. Asia 1 causes the second largest number of disease outbreaks in India. As there is no information available with respect to the extent of antigenic variation in FMDV type Asia 1, we have studied FMDV isolates from vaccinated and unvaccinated animals from different parts of the country and compared their relationship with Asia 1 vaccine virus. The immunogenic, hypervariable region of viral protein 1 (VP1) gene was amplified by RT-PCR and sequenced. Analysis of sequence data showed that the viruses from two field outbreaks of Southern India were closely related to each other when compared to the isolate from the North and all the three isolates are away from the vaccine virus.
