Biopolymers and cell. 2000; 16 (4): 312 - 319

Analysis of antigenic structure of Potato Virus M Ukrainian strains

S. S. Viter, T. Yu. Tkachenko, L. P. Kolomietz, Yu. L. Radavsky

The antigenic structure of two Ukrainian strains VI and U7 of Potato Virus M (PVM) was studied by using three mouse monoclonal antibodies (MAbs). Tryptic fragments of PVM coat protein (CP) 22Glu-Lys35 and 22Gly-Lys35 were found to be recognised by two MAbs, M6D5 and M9GJ. The amino acid substitution Glu -* Gly at the position 22 of PVM 117 coat protein did not affect antibody binding to both tryptic fragments and PVM CP. Mob M9GJ interfered with MAb M4C1 in dot immunobinding assay. Synthetic peptide PI4, corresponding to tryptic fragment 22Glu-Lys35, inhibited the interaction of MAb M6D5 with CP and peptide P14 more effectively than that of MAb M9GJ. The modification of the side chain positive charge of Lys35 to negative one in tryptic peptides 22Glu-Lys35 and 22Gly-Lys3S using citraconic anhydride resulted in a two-fold increase of the reaction of MAb M9GJ and slightly reduce the interaction of MAb M6D5 with both fragments. On the basis of these results, it was concluded that three PVM-specific epitopes are located at the N-terminal region and form original immunogenic site of PVM coat protein. MAbs M6D5 and M9G1 recognise sequentially overlapping epitopes and the common site for both epitopes is presented in the fragment 22Glu/Gly-Lys35. MAbs M4C1 and M9GJ recognise either overlapping, or conformational approximated epitopes.