ANTIBODIES RAISED IN A NATURAL HOST AND MONOCLONAL-ANTIBODIES RECOGNIZE SIMILAR ANTIGENIC FEATURES OF FOOT-AND-MOUTH-DISEASE VIRUS

Swine polyclonal antibodies directed against a major antigenic site (s ite A) of foot-and-mouth disease virus (FMDV) of serotype C, and monoc lonal antibodies (MAbs) which recognize different epitopes within this site, have been compared with regard to reactivity with a panel of sy nthetic peptides. The peptides used represent different segments or va riant sequences of site A, and their reactivities reflect differences in antigenic specificity. The results indicate a remarkable immunochem ical similarity between the sire A epitopes defined by murine MAbs and those recognized by antibodies elicited in a natural host of FMDV. Th is similarity further validates previous conclusions, based on analyse s with MAbs, on the relevance of amino acid substitutions at a few cri tical positions on the intratypic antigenic variation of FMDV in the f ield. They also give further support to a dual function of the Arg-Gly -Asp motif of the G-H loop in cell attachment and in the recognition b y host antibodies, as recently documented with the elucidation of the three-dimensional structure of an antigen-antibody complex of FMDV. In addition, the results encourage the use of extended panels of well-ch aracterized MAbs for a precise molecular analysis of the antigenic var iation of FMDV, and of other viruses, in the field. (C) 1995 Academic Press, Inc.