The E2 protein is the major glycoprotein of the envelope of Bovine Viral
Diarrhea virus (BVDV). This protein is highly variable and induces a strong immune response
with the production of neutralizing antibodies; therefore this protein is widely used to set up
vaccines providing complete protection from the infection. In persistently infected animals it
was assumed that immunological tolerance favoured maintenance of an antigenically conserved
population of persisting virus over the emergence of quasispecies which stimulate an effective
immune response. However, further studies showed genetic variability of BVDV in the E2
region and 5’UTR region in persistent infected animals. The aim of our work was to study the
variability of BVDV analysing the antigenic properties of clones obtained by cloning PCR
products of two organs from mucosal disease affected animal
