Differentiation of classical swine fever virus (CSFV) strains using monoclonal antibodies against structural glycoproteins.

Two panels of monoclonal antibodies (mAbs) against the classical swine fever virus (CSFV) envelope glycoproteins E2 (12 mAbs) and E0 (11 mAbs) were established and tested by immunoperoxidase binding assay against 135 pestivirus strains and isolates. Variability of the binding pattern was demonstrated for CSFV and also for bovine viral diarrhea virus (BVDV) strains and isolates. The panels of mAbs against E2 and E0 led to very different reactivity patterns. Particular mAbs against E2 reacted with (i) all CSFV isolates, (ii) only 4 out of 126 CSFV isolates, or (iii) about 90% of the tested CSFV isolates and 78% of ruminant pestivirus isolates. Anti CSFV E0 mAbs allowed the detection of a greater variability among the CSFV strains and isolates than the anti E2 mAbs. None of the 11 anti E0 mAbs recognized an epitope conserved for CSFV or showed crossreactivity with ruminant pestiviruses. The use of both panels of mAbs against two CSFV structural glycoproteins led to the discrimination of 21 antigenic types of CSFV strains and isolates. The described panels can be used to trace the origin of CSFV after outbreaks of the disease.