A novel long Vp1 gene deletion include G-H loop in FMDV Type A-87 vaccine strain of Iran

The initial step of infectious process of FMD virus is attachment to specific cell surface molecules . The G-H loop contains a highly conserved Arginine-Glycine-Aspartic acid (RGD) sequence has been implicated in receptor binding site . We analyzed the VP1 gene sequence of FMDV Type A-87 vaccine strain of Iran. This vaccine strain was the result of 150 serial cytologic passages. The primary sequence alignment with other sequences derived from GenBank shows 39 nucleotides deletion in vp1 FMDV Type A-87 gene sequence, which is missing of 13aa[RGDLGPLAARTAA]. Because of the natural deletion in this virus subtype the RGD sequence in the G-H loop was lost. In spite of losing RGD sequence, the virus grows on BHK-21 suspension cell culture and shows CPE after 16-18 hrs. The PD50 of 13aa-deleted A-87, indicates a satisfactory immune response in guinea pigs.