Peptides were synthesized, that correspond to cleaved and trimmed carboxyl termini of the F polypeptide regions of fusion (F) protein precursors (F proteins) in four different strains of Newcastle disease virus (NDV). These peptides differed only within the four carboxylterminal residues and represent F polypeptides of virulent (AV), low-virulence (EG) and avirulent (V4 and WA) pathotypes of NDV. Polyclonal rabbit antisera against each peptide reacted with their corresponding monomeric F polypeptides and F protein oligomers as analysed by immunoblotting of egg-propagated virions. Bidirectional cross-reactivity was observed between V4 and EG antisera and F polypeptides which differ only by a single variation of lysine and arginine at position 3 from their carboxyl termini. The other two antisera (AV and WA) were specific for their corresponding F polypeptides. All of these antisera were shown to react in a strain-specific manner with intact egg-propagated virions in an ELISA. A previously described antiserum, designed to target the haemagglutinin-neuraminidase (HN) protein precursor (HN protein) of avirulent strains of NDV, has been shown to be specific for residual HN protein of avirulent virions propagated in embryonated chicken eggs. Whereas the antiserum targeted at the carboxyl terminus of the V4 F polypeptide did not react with F proteins of cell culture-propagated strains in immunoblotting, antipeptide antibodies targeted at another region of the F polypeptide and a segment of the F polypeptide did react with the F protein from infected cells. These data are consistent with inclusion of the terminal carboxylate of the F polypeptides in the recognition determinants of the antibodies targeted at the carboxyl terminus of the V4 F polypeptide. The antisera described herein are ideally suited to rapid immunochemical pathotyping of NDV isolates and immunochemical characterization of the sites of intracellular cleavage activation of F and HN proteins and may be useful for defining interactions involved in F protein folding.


Article metrics loading...

Loading full text...

Full text loading...


Most cited this month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error