Reduction of Respiratory Syncytial Virus Titer in the Lungs of Mice after Intranasal Immunization with a Chimeric Peptide Consisting of a Single CTL Epitope Linked to a Fusion Peptide

AbstractIn the work described here, the effect of intranasal immunization of BALB/c mice with synthetic chimeric peptides consisting of a cytotoxic T-cell epitope (amino acids 81–95) from the M2 protein of respiratory syncytial virus (RSV) and a fusion peptide (amino acids 113–131) from the F1 protein of measles virus on response to challenge with RSV has been assessed. Three intranasal immunizations with the chimeric peptides without adjuvant induce peptide- and RSV-specific cytotoxic T-cell responses (CTL) at 1 or 3 weeks after the third immunization. The CTL responses significantly declined at 6 weeks after immunization. Furthermore, viral load in the lungs following challenge with RSV was significantly reduced in mice immunized with the F/M2:81-95 chimeric peptide compared to control animals at 1 or 3 weeks after immunization and no reduction of RSV titers was detectable 6 weeks after immunization. The CTL activity induced by F/M2:81-95 was therefore short-lived (less than 6 weeks) but was significantly correlated with the reduction in viral load in the lungs