Response of foot-and-mouth disease virus C3 Resende to immunological pressure exerted in vitro by antiviral polyclonal sera.
The foot-and-mouth disease virus (FMDV) shows a remarkable antigenic variability. Like other RNA viruses, FMDV has a high mutation rate and it has been proposed that selection exerted by antibodies of the host could play a major role in its evolution. In this work, antiserum-resistant variants of FMDV (Nr variants) were selected upon 25 serial passages of a cloned C3 Resende strain on secondary monolayers of fetal bovine kidney (FBK-2) cells in the presence of subneutralizing levels of antiviral polyclonal sera (APS). After serial passage under immune selective pressure, the five Nr variant populations selected from five independent serial passages--their controls remaining unmodified--acquired the following characteristics: (i) increased resistance to neutralization by APS; (ii) five different antigenic specificities detected by enzyme-linked and neutralization assays using monoclonal antibodies; (iii) the same modification (residue 146, S to L) at the major antigenic site of VP1 (G-H loop, the 135-160 region); and (iv) specific changes for each Nr population outside the major antigenic site of VP1 at residues 46, 48 and 49 of the 40-60 region of VP1 (B-C loop). These results extend our previous work on selection of Nr variants using polyclonal sera, and add new information with regard to antigenic variation, mainly concerning the involvement of the 40-60 region of VP1 in the process of immune selection.
Schiappacassi
M
M
Cátedra de Virología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Argentina.
Rieder Rojas
E
E
Carrillo
E
E
Campos
R
R
D000595:Amino Acid Sequence; D000914:Antibodies, Viral / Q000276:immunology*; D000940:Antigenic Variation / Q000276:immunology; D000956:Antigens, Viral / Q000235:genetics / Q000276:immunology; D005537:Aphthovirus / Q000235:genetics / Q000276:immunology*; D002213:Capsid / Q000235:genetics / Q000276:immunology*; D036022:Capsid Proteins; D002460:Cell Line; D000939:Epitopes / Q000276:immunology; D008969:Molecular Sequence Data; D009500:Neutralization Tests
D000914:Antibodies, Viral; D000956:Antigens, Viral; D036022:Capsid Proteins; D000939:Epitopes; C442501:VP1 protein, Foot-and-mouth disease virus