Antigenic analysis of bean pod mottle virus using linear and cyclized synthetic peptides

The antigenic structure of the comovirus bean pod mottle virus (BPMV) was studied using synthetic peptides selected on the basis of the exposed location of certain regions of the viral protein. Three regions of domain A, four regions of domain B and two regions of domain C of BPMV coat protein were studied. Each of four regions were synthesized in the form of linear and cyclized peptides while the others were synthesized as linear peptides only. The peptides were tested for their ability to be recognized by antibodies directed against BPMV. The peptides were also used for producing rabbit antisera, which were tested for their ability to react with various BPMV antigens as well as with the linear and cyclized peptides. All the peptides were found to correspond to epitopes of BPMV coat protein. Several of the antigenic sites of BPMV located on exposed loops of the coat protein occupy positions which correspond to known epitopes in the structurally related picornaviruses. Only in some cases did cyclization sufficiently improve the level of conformational mimicry between peptides and the viral protein to allow cross-reactions between them to be observed.