FINE SPECIFICITY OF THE ANTIBODY-RESPONSE TO A SYNTHETIC PEPTIDE FROMTHE FUSION PROTEIN AND PROTECTION AGAINST MEASLES VIRUS-INDUCED ENCEPHALITIS IN A MOUSE MODEL

A synthetic peptide representing residues 397-420 from the measles vir us (MV) fusion (F) protein was tested for its structure, immunogenicit y and protective capacity against intracerebral challenge with a neuro adapted strain of MV, Analysis of the peptide by mass spectrometry sho wed that it was linear, despite the presence of two cysteine residues in the sequence, Circular dichroism spectroscopy highlighted a weak pr eference for the peptide to adopt an alpha-helical conformation. The p eptide was shown to be immunogenic in BALB/c and C57BL/6 mice after in traperitoneal immunization in Freund's adjuvant, and anti-peptide anti bodies from both strains of mice reacted with the MV as a solid phase antigen on an ELISA plate, When the fine specificity of the anti-pepti de antibody response was examined using overlapping 8-mer peptides, se rum antibodies from BALB/c mice recognized the region between residues 407-417 whereas antibodies from C57 BL/6 mice recognized the region 4 08-420 of the 397-420 peptide sequence. Although anti-397-420 antibodi es had no demonstrable neutralizing activity, protection against chall enge with a neuroadapted strain of MV was demonstrated following activ e immunization with peptide in C57 BL/6 mice or after passive transfer of anti-peptide antibodies in BALB/c mice. These findings highlight t he importance of the 397-420 region in the induction of protective ant ibodies in the MV encephalitis mouse model, and suggest that this epit ope might be a good candidate for inclusion in a future MV synthetic p eptide vaccine.