Differentiation of peanut clump virus serotypes by monoclonal antibodies

Targeting highly conserved 3'-untranslated region of pecluviruses for sensitive broad-spectrum detection and quantitation by RT-PCR and assessment of phylogenetic relationships

The 3'-end region of many virus isolates has been shown to possess conserved sequences in addition to the presence of numerous genomic and subgenomic RNAs. Utilizing these sequences, a broad-spectrum reverse transcription-polymerase chain reaction protocol has been developed to detect all the known Indian peanut clump virus and Peanut clump virus isolates, that cause peanut clump diseases in West Africa and India. The primers were targeted at the highly conserved 3'-untranslated regions of the PCV RNA-1 and RNA-2. The conservation was confirmed by sequencing these untranslated regions of RNA-1 for six isolates and RNA-2 for one isolate. The conserved structure of the RNA-1 and RNA-2 was observed and the importance of this region for the virus survival was confirmed. The primers were also designed for virus quantitation using a Taqman(®)-based real-time RT-PCR. The use of RT-PCR and real-time quantitative RT-PCR improved the sensitivity of PCV detection compared to ELISA. RT-PCR also led to the detection of IPCV and PCV on two new natural hosts: Oldenlandia aspera and Vigna subterranea. Real-time RT-PCR is considered to be an ideal tool for identifying resistant sources to both IPCV and PCV.

Use of monoclonal antibodies for the identification of different antigenic domains in apple chlorotic leaf spot virus

Thirteen monoclonal antibodies (Mabs) specific for apple chlorotic leaf spot virus (ACLSV), produced by the somatic cell hybridization technique, were used to investigate the antigenic structure of the virus. Epitope specificity studies showed that these Mabs defined in ACLSV particles seven independent antigenic domains, representing at least eight distinct epitopes. One of them was present only in virions and not in dissociated subunits. It appeared that the interaction between a Mab and the virus could, in some cases, induce conformational changes in the viral particles which enhanced the binding of others. Twenty nine virus isolates differing in geographical origin, primary hosts and symptomatology were tested with these monoclonal antibodies by ELISA. With the exception of two Mabs which did not react with three cherry isolates, and one Mab which did not react with one plum isolate, all of them recognized all ACLSV isolates tested.